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  1. The downward slide into winter begins. Post your Obs/Discussions here.
  2. Well, PTC has been designated off the Florida coast. Models have really honed in on the NC coast from Cape Fear to Hatteras as a landfall threat. Models are also indicating this could become fully tropical before landfall, and possibly strengthen to a high-end TS. As a short notice event, folks should probably prepare for the equivalent of a hurricane landfall. The forecast track also could be nudged west, as some models are showing. Areas from the Triangle-east need to pay attention. This is likely to produce higher impacts than Idalia for the state.
  3. There is likely going to be some warmth during mid-month - and maybe extreme. So, I am not starting this thread w/ any sugar coating. That said, models are sniffing out a cold shot to start this month which wasn't seen on some modeling even 24 hours ago. In life we go one day at a time. Let us not borrow the troubles of tomorrow until they arrive. 12z Yesterday and 12z today of the GEFS.
  4. Since we do have a variety of forum posters in areas that will see snow/sleet/ZR - at least initially and on the backend, plus there is a flood threat, along with some potential advisory-level winds and possibly record breaking cold, decided to go ahead and make an obs thread. Currently misty and mostly virga and 36 with dp 32 here in NW Philly.
  5. Day one of met fall, highs in the 70s, humidity fell through the day. Hard to beat after the heat, humidity and rain that ended met summer.
  6. February discussion for all things winter in the Tennessee Valley Sub-forum. When we have a likely event 2-3 days out we can create an individual thread for said storm. It helps for record keeping purposes as a lot us like to look back on old threads to learn, etc. Hope everyone is doing well.
  7. January discussion for all things winter in the Tennessee Valley Sub-forum. When we have a likely event 2-3 days out we can create an individual thread for said storm. It helps for record keeping purposes as a lot us like to look back on old threads to learn, etc. Merry Christmas to all as well, I hope everyone has a great holiday.
  8. 454AM Wednesday Jan 12: title and tags adjusted to drop Saturday, focus late Sunday-Monday morning for what appears to be an 18 hour storm of snow-rain-snow. Heaviest snow tends to be modeled west of the I-95 corridor but ensembles still warrant continued concern for the axis of heavy snow including I95. At this point far too uncertain but where it snows for 12 hours, widespread 6+" seems likely. Also a 6 hour period of potential 50 kt inflow gusts is possible for the coasts Sunday morning and if it occurs with the dawn Monday high tide, would result in coastal flooding, magnitude unknown. This does not appear to be a long duration storm (24 hours+) but it should be intense for a few hours Sunday night or Monday morning. Again track uncertain, and sensitive to the intensity of the surface low. There still is opportunity that this will track too close to our area for much snow but there are several days to adjust the track and resultant precipitation type. It does appear there will be a general inch to 1.5 inches of qpf with this system, maybe thunder too. A big storm with large scale impacts entire east coast-Appalachians. The only reason I didn't highly stronger wording for impact, is that this will occur later Sunday and the following Martin Luther King Jr. Holiday. --- At this 6-7 day lead time 8PM Sunday Jan 9 issuance, options are fairly wide open. For now, a light or moderate event 'seems' likely but absolutely not a lock, nor is a heavy event excluded. This event still could be demolished to zero by what happens off New England on the 14th, or what follows between the 19th-22nd. However there already has been discussion the past several days for the coming weekend. Ending 12z/9 the past 6 cycles of the ECMWF op, the last 4 cycles of the CMC GGEM [LI 3 cycles, I84-4 cycles] have some sort of snow event, especially I84. Maybe the GFS via it's 18z/9 cycle is shifting snow emphasis on the 16th for our area instead of bombing off the coast on the 14th? Having reviewed ensembles: 12z/9 EPS/GEFS/NAEFS all have some sort of frozen event is coming to the northeast USA, along and north of I80 including LI. Have added the broad coverage low chance WPC D7 issued at 17z/9, the EPS 24 hour qpf ending 12z/17 and the 12z/EC 850 MB low (GEFS so far has nothing, still favoring the 14th but not as far south and west as previous). NAEFS products for 00z/17 are added including previous 24 hr qpf, 00z sfc temp in C, and the sfc pattern. There will be quite a few model changes-conflicts and this could end up having been a wasted effort... but it seems worthy of further scrutiny as our next possible significant snow or ice event for at least a portion of the NYC subforum.
  9. Modeling is favoring the development of some sort of extensive precipitation event along the east coast, with either the first or second of two short waves carving a pretty deep, albeit temporary 500MB trough in the eastern USA between next Friday and Monday. At least until Tuesday the 18th when the results of the 16th-17th are in, lets hold off on single model solution hype. Three graphics added, two from the 08z/16 WPC issuance. Low prob 3+" of snow, and the third was the CPC D8-14 hazard graphic, it paints a small chance of heavy snow just north of I-80 again (just like this 16th-17th event). It also ,not shown here,has a high chance of very cold air here 22nd-28th. 7AM/18 Update: I've updated the thread title-no guarantees our NYC subforum will share in what is coming to the Demarva-Carolinas but it seems models are gravitating to a decent snowstorm for a portion of the mid Atlantic and possibly through southern NYS-southern New England. 718A/21: Changed thread title to add part one was about 150mi too far southeast (slightly less average error for a D5 forecast than NHC on tropical systems). Withdrew wind from the tag. Otherwise the overall intent of the thread remains the same.
  10. While uncertainty exists on the target for a rain to hazardous brief commuter significant snow event, a thread has been started to take the load off January. Thursday morning I84-NYC-PHL: Looks like 1-3" of snow in a 6 hour period centered on sunrise, with potential significant impact to morning travel due to temps falling to freezing during snowfall. There is model uncertainty on amounts. Snow could fall for an hour at 1/2-1". I84 itself seems to be on the northern fringe where snowfall could be less than 1". Amounts also depend on how fast the preceding predawn rain showers change to snow but I am confident of a snow event, just not confident who gets the biggest impact. Tomorrow morning we should have a much better idea of travel impact. I would add that climo on something like this probably favors an inch or less NYC CP, but I do think there is going to be a narrow lane of more than 1" per multiple model indications. NWS ensemble risk of greater than 1" is less than 30%, so that is the reasoning for calling this Potential, in the headline. 656PM: adjusted Title to OBS-NOWCAST. Added freezing rain and rain to the tags. First batch of mixed precip should arrive ne PA, extreme nw NJ and se NYS around 1-2A as snow freezing rain-rain, but the primary batch is slated to occur between 5AM and Noon as snow north and west of NYC til NYC-Li and NJ I95 changes to snow around 7-830A. It ends from northwest to southeast, first in nw NJ by 11A and then NYC by 1P and further southeast during mid afternoon. Amounts near I84 of a dusting to possibly 2" with a general 1.5-4" in the core of the event from near NYC/LI-down I95 in NJ. It may briefly snow 1/2mi moderate for an hour or so. Still a little uncertain where the 4 inches are...probably NJ/LI.
  11. Cyclic modeling of the EC/GGEM and ensemble portion of the GFS since this weekend has been developing a fast moving late developing coastal low, resulting in a period of precipitation occurring mainly between midnight and 6PM Friday. Tracking and therefore precipitation type are uncertain but recent ensembles were offering at least 2" of snow to portions of our area, the EPS furthest west and the GEFS/GEPS a bit further east. The GFS op model has been generally offshore. If the low develops further north or further east, very little snow will occur here. Right now 850MB Low development looks too far north for a moderate event but probably worthy of monitoring and trying to figure it out. Based on the model performance for the 1/3/21 grazer snow, we may not know much til we see the NAM consistently give us 1/4" qpf in frozen form with more than 2" of event Total Positive Snow Depth as shown on the Tropical Tidbits web site. 12z/3 500MB ensemble plots below serve as a baseline to witness future modeling departures, GEFS top and EPS next. IF this approaching short wave ends up weaker or further north, it will be difficult to receive meaningful snow here. At 321PM added the 16z/3 WPC D4-5 probs of 1/4" frozen W.E. (lower 2 graphics) which bridges Friday morning 12z/7. The darker green is greater than 30% chance.
  12. 637AM Sunday: : headline updated to Major near blizzard and added power outages. Major near blizzard Nor'easter coming. I would not plan on driving anywhere on Monday in northern NJ, ne PA, se NYS and ditto CT Monday afternoon-night, MA Monday night. NYC my guess is a foot, possibly more before mixed Monday night. Otherwise, amounts between 1-2 feet from I78 northward with lesser 8-18 inches CT and MA where rain/sleet invades later Monday night. Isolated 30" possible nw NJ, or ne PA into the Catskills by the time this storm ends early Wednesday.. Drifts 3-4 feet. Power outages possible Monday afternoon and night from northern NJ northeastward to CT and Boston from a combination of heavy wetter (heart attack for the hear tcondition vulnerable) snow and northeast wind gusts of 40-55 MPH. Snow starts central NJ around 3 PM, northern NJ-ne PA 6-10P, CT around dawn Monday. Worst of the storm NJ/PA sunrise Monday-midnight Monday night, CT Monday afternoon-night. Coastal flooding may be major near the midnight Monday high tide cycle? Follow NWS. ---- 615AM Saturday: Imperfect probably messy big snowstorm is coming, imperfect in that modeling the past 24 hours is drifting north and suggesting a dry slot late Monday will allow enough warming for sleet (rain LI) to I80 including all of I95 Monday night so that the stratiform burst of 1-2"/hr Heavy snow during Monday, especially afternoon, becomes bands of snow in the interior late Monday night-Tuesday, some areas probably recovering Tuesday with several hours of no precip. So, my own single forecaster point of failure but use of ensembles could be too pessimistic about the sleet/rain intrusion. For NYC... I'll start with 6" with possibly as much 1/2" late 31. Hope that its mostly snow after 00z/2 but even if, snow ratios may be down to 7 or 8 to 1?? I dont' want to cap NYC since am uncertain about dry slot. Sleet/rain/freezing rain may be getting involved Philly to Toms River during Monday morning. There may be a period of near blizzard conditions on LI centered Monday afternoon? BUT, I don't want to call it a blizzard for fear of easily missing criteria. The point of this paragraph, is that I think Monday, especially afternoon should be the worst period of travel and if models continue this, in future cycles through Sunday morning, then I think it would be a recommended no travel for that 6-12 hour period to limit accidents and allow plows to maintain passable-less slippery conditions for first responders. Snow may be wet on LI/Monmouth-northern Ocean Counties in NJ if 6" at 32-33F, we would have power outages... still too early to be sure. CT I84... continue to notice some multimodeled lesser snowfall there, so while I think a big snow there, cautioning myself. Coastal flooding: see NWS statements/flood watches already posted and no change from yesterday with the late Monday evening high tide cycle most favored for flooding (within 2 hours either side of the time of high tide) Graphics are the 00z/30 EPS as a base amount, the 00z/30 EC IR prediction for 06z/Tue showing the dry slot penetration, and the NWS 09z/30 prob for 6" or more of snow by 12z Tues. That's the reasoning basis for this update.
  13. Overall assessment as modeling monitored through 6AM Monday. Complex intermittent snow to sleet to freezing rain scenario with potential for 0.1"-0.5" measurable snow sleet NYC-LI while parts of the I84 corridor receive spotty 1 to possibly 2" snowfall. It should begin in NYC/NJ/ne PA/se NYS between 11A-2P and CT maybe between 2-5P. While treated surfaces in metro NYC should be mostly wet, caution is advised everywhere. The National Weather Service has advisories posted for the I84 corridor. I think this could be more of a problem further south in NJ. Also: the worst of this for some of our area could occur near sunrise Tuesday if it clears after midnight and everything refreezes into a frosty icy mess, especially driveways, sidewalks-steps. No thread expected (at least not yet) for late Tuesday-early Wednesday where w wintry hazardous mess is expected again-at least for the high terrain of I84 (strong mid level Frontogenesis). A few graphics to give an idea of what should occur. 631A/27
  14. Many models have a little snow or ice for our area next Wednesday the 8th, possibly ending as rain? WPC Friday afternoons forecast has a half inch+ of qpf for our area next Wednesday and a 30-49% chance of 3+" of snow or 1/4 inch combined sleet/snow. Click the graphics. That's not too bad for a day5-6 forecast. I may have overreached on PROBABLE hazardous???? I do think there should be a little ice, at a minimum over the I84 high terrain. The rest of the area much more uncertain. We should be close to the right rear quad of an upper level jet core centered near Nova Scotia (130 knots 200-300MB) next Wednesday (see EPS 18z Wednesday 300MB), this behind the strong negative tilt short wave departure of Monday. A weakening 500MB short wave from the upper Midwest Wednesday morning crosses into northern New England by Thursday morning. The 850 Low is north of our area. Snow thicknesses are marginal especially south of I84, so that snow amounts this far in advance are VERY uncertain and likely to be less than 3" rather than more. Some sort of light to possibly moderate ice-snow event should occur in parts of our interior Wednesday Dec 8. One consideration is the qpf being less than currently advertised which would reduce amounts. This thread is posted to focus anyone's interest into the discussion. LI-coastal NJ--- primary modeling may eventually favor your area but for now, I think the primary ensemble considerations for a 6 to 18 hour period of hazardous wintry weather next Wednesday is to the northwest of I95. TAGS and Thread title may change this weekend or early next week. 717PM/3 Dec 2021 6AM Wednesday the 8th: converted this thread to OBS-Nowcast. No other change.
  15. Well, we are just one season away from winter. Nice to have a respite from the heat this week as the remnants of Ida depart the area. Thoughts and prayers for all of those affected by the hurricane along the Gulf Coast. Rainfall along the far eastern valley has been steady but reasonable - more as you go west I am nearly certain. This morning features light rain/drizzle and very low cloud decks. Lows in the northern valley are supposed to get into the 50s during the next few nights, and that is welcome news! Saw the first evidence of maples beginning to change color this morning. There is this one maple in our neighborhood which always changes first. Some of the dogwoods are beginning to show red in their leaves. Sycamores along the river are showing some yellow. For sure, some of that could be heat stress. Well, it is the first day of meteorological fall. I suspect this season will feature a quick snap to winter time temps late in the season. I am thinking warm early-mid fall, and then a sudden flip to cold. Somebody please fire-up an obs thread and also a banter thread for fall.
  16. I’ve seen discussion in multiple threads, so here’s one for the storm. Should be a good widespread rain across a lot of the area. Tropical storm wind gusts working up the coast. Should be some gusty winds with whatever remains of the core as it moves through the Carolinas and into Virginia. Tomorrow afternoon could feature a tornado threat from the SC low country in NC coastal plain
  17. 548A/17: Advisory situation may be coming to a portion of the forum-not a lock, for the Friday morning commute, despite probable less than official criteria amounts NYC/LI due to sharply falling temps to between 25-30F with sleet to snow in the 5A-8A time frame and gusty n-ne wind of 30-40 MPH. Snow ends sometime late morning-midday with temps recovering above freezing in the afternoon. Wind gusts for a few minutes between midnight and 8A could reach 50 MPH in parts of the area. Added wind event to the thread. Snowfall for NYC-LI T- at most 2", while a bit heavier seems likely I84 corridor extreme nw NJ of 1/2 to possibly 3". Think the best chance for 2+" in our subforum is CT. If the precip ends more abruptly, then we escape the advisory and amounts will be under 1" with the lesser snowfall of the 00z/17 cycle ICON, UKMET, 12K NAM considered. Note: as the transition to snow occurs, the first hour or two may be melting on most surfaces and certainly pack down to snow ratios less than 10 to 1, possibly closer to 7 to 1 or something like that. Some of the modeling has complications not only Friday, but also next Monday. For Friday, there could be two bands of halfway decent accumulative snow, one across I84 and the other just south of I78 across central or s NJ? TBD. Then, next Monday: the 00z/17 EPS and GEPS want to form a deep cyclonic circulation off the mid or south Atlantic coast this weekend and drift it north or northeast early next week, spreading rain back into the area. Depending on latitude of formation, will determine how much warming aloft occurs. ENS have 850 temps in the +3/+4C range next Monday, too warm for snow, provided all the excessive height rises and warming aloft that is modeled in the northeast occurs. If that shifts north, then there is a real long shot (very low chance) we might be looking at some marginal thermal profiles for a bit of wet snow in CT. At this time, I wouldn't be promising mostly clear skies and dry weather for Sunday afternoon-Tuesday morning. Added the 0841z/17 NWS ensemble prob for >1" of snow Friday. You can see the concern for going too heavy. --- Strong cold high pressure approaching Quebec Friday-Saturday will combine with an eastward moving and opening closed low in the Ohio Valley, to permit a period of wet snow here on Friday. Duration and intensity are uncertain along with resultant amounts (T-2"?) and will be related to the proximity of the positive tilt 500MB trough. For now, this could be considered a back-back system, modeled way back as early as the 00z/7th modeling cycle, that could provide as much snow to the parts of the forum, as whatever occurs late 16-17. The fresh influx of colder BL air from the north may even allow measurable snow into NYC? Most of the modeling favors a few hours of snow Friday morning with marginal accretion temps. Still, for an event at the tail end of winter for NYC, it could provide a little fun? This especially if the GEPS-NAEFS solutions of keeping the low close enough to continue significant qpf going into early Saturday. Then we would be talking about some potentially plowable snow to near NYC, but this is an outlier possibility for now and best at this time (D5) to favor conservative ,minor impact, at worst. Finally, if this storm system does hang around nearby to our south all weekend (low chance), it might make a northward drift into the CT/LI part of the forum Monday the 22nd, but by that time, the snow temp profiles have warmed to rain (probably exhausted the snow profile cold air supply).
  18. 626A/16: Not much. 00z/16 EC op and 06z/gfs v16 (para) are best chance of a little snow this afternoon-night, mainly n of I80. Doubt if NYC/LI can do more than T of snow-sleet if those elements occur. nw NJ might see spotty freezing rain showers tonight. Thread now converted to OBS-NOWCAST if and as needed. --- 543A/15: Below is my mental mesh of modeling (lower than usual confidence) on what happens late Tuesday-early Wednesday. I78-I84 corridors-periods of light snow, sleet or freezing rain likely begin Tuesday afternoon or evening and ends as rain Wednesday morning. Modeling uncertain-so my confidence on how much ice/snow is less than usual. There is a pretty good chance of at least spotty icing in PA/NJ that may require treatments. If it's snow, just a slightest covering to maybe an inch or 2 but can't promise all snow except CT/MA. I can see the need for some caution traveling untreated surfaces Tuesday night-early Wednesday. One model group: The GFS v15/16 have been hitting the snow harder along w the GEFS, for se NYS/extreme nw NJ/extreme ne PA with potential for 4" high terrain, if no ice. One of my concerns is ice in ne PA/nw NJ. For NYC-LI: Even with snow snow or sleet in the air, NYC may not measure anything more than T if it's light. If it manages the 00z/15 GFS scenarios, then yes, minor amount there. Better chance spotty minor amounts LI (under 1"). Follow the models. I'd like to see models, other than the GFS, become more robust. For now, the GFS solutions are outlier heavier outcomes. I don't know what to believe but the uncertainty on qpf volume, as well as thermal profiles suggest conservative expectations. --- 707A/14: Looked back on the original post of the 7th... seems like we may be onto something, but considerable model uncertainty, which tells me nothing big and impact minor, as always intended, but at least, I think, targeting the NYC subforum with a wintry event. In checking back the snow snow shower threat for the 14th was introduced on the 9th. Wind driven dustings of flurries I84 corridor with maybe a spotty half inch or so? (far N CT & Pocs). Wind gusts midday-this afternoon similar to those of early Saturday, maybe a touch higher with isolated power outages---generally 40-50 MPH. (I missed forecasting the gusts of early Friday where we in Wantage had 43MPH-320A). No OBS thread anticipated since trees not leaved. Can post obs in March 2021, unless you wish an obs thread for the midday-afternoon wind. Just let me know. Tuesday evening-Noon Wednesday: I78 northward to I84 (Tuesday night-Wednesday morning). Looks like (not guaranteed) a period of snow and possibly ice. If snow, generally an inch or less (spotty 2" possible high terrain?). iI ice, it would be minor but hazardous for untreated surfaces during the Tuesday night hours. For NYC-LI: same old uncertainty. EC for at least 3 cycles continues to insist on light snow with potential for a few tenths? I don't know. I am aware the the EC overall was always driest well in advance and also much slower to arrive (apparently handling the Rockies closed low much better than the GEFS/GEPS). Now am seeing some "possible" minor intensification of the short wave crossing our area early Wednesday. Anyway, road impacts should be negeligible except high terrain untreated's at night. ---- 554A/13: Maybe WY/CO utilized too much of the energy, so despite the short wave crossing our forum directly ~ Tuesday night, this thread will probably have been a waste of time. Modeling has dried up. Multiple 00z/13 ens and few models give us spotty light snow (or ice) Tuesday or Tuesday night but can't see this being a hazard now. In case it does the long odds minor snow measure in NYC, this might be the last decent chance of measurable snow in the city, associated with a -NAO? So, while the door seems to have closed, still worth a look once a while. In the meantime, a few flurries (unstable lapse rates as cold dry aloft sweeps south through New England) seem possible in much of the forum Sunday (14th), with scattered dustings in ne PA, CT, se NYS. --- 648A/12: Whittled down the days from 14-16 to just 16th. Lots of words and uncertainty for a potential modest wintry event. This should be a bit simpler by now. 00z-06z/12 GFS series is the only primary operational model holding onto a wintry event while most other operational models have dried up. That modeling disparity is not a good sign for an event as we draw closer to whatever transpires. I do have some doubts about how this works out. By 430PM (2130z/12) this afternoon, you'll have a pretty good idea via the 84 hour NAM whether the GFS is out to lunch by checking the leading edge of whatever the NAM has against the predictions of the GFS. For now, I think the 12z/12 84 hr NAM has to have leading edge close to CLE-PIT, and the 18z cycle something to BWI-AOO at 84 hours, and the RGEM has to pick it up as well. If not, then prospects for the GFS solutions are probably evaporating and this c(w)ould be a wasted thread-busted expectation. Of course the 12z/12 volatile EC will be available. It's possible the dry air associated with cold surge Sunday-Monday will evaporate the oncoming warm front- vort max associated wintry precip, as the decaying Midwest short wave shoots into the confluence zone here in the northeast. GEFS and even the EPS have a nice RRQ of the upper level jet pulling for us, with weak 850 WAA but lack a little punch on the LFQ of the upper level jet near 35N latitude. 00z/12 GEPS and 00z-06z GEFS continue with modest qpf and relatively cold, so that 2-8 hours of snow-sleet is modeled coming for most of the NYC subforum Tuesday, including NYC-LI with a base snowfall near 1" (potential 4-5" highest elevations of I84 but that is completely qpf dependent). It should begin ~6A western NJ/se NYS, maybe 8A-Noon NYC/CT. It would then end as rain LI-NJ Tuesday night-early Wednesday along and s of I80 but possibly as freezing rain I84 corridor. Again, my assessment is predicated on ensembles of GEFS/GEPS. It's not big but it appears to me to be the best wintry option for NYC the next week or so. The back-back (18-19 second event) is even more uncertain with respect to wintery elements and if there are back-back snow-ice events, I think best chance I84 corridor, which does not guide me to a thread, since 18-19 currently doesn't have big snow prospects for NYC metro. 604A/11: will post additional impressions around 745A. Running a little late. As I see it... game on... if these models can finally hold serve as intended when the thread started. Even NYC might see a bit of snow. IF, in the future, all this fritters to minuscule under 1" amounts of snow and only n and w of NYC, then this thread will hold for OBS/NOWCAST. That's me thinking downside. As of now, 00z/11 UK/EC ops trying for a hazardous snow event n of I80 (hills best for road acc at this mid March sun angle). I just haven't caught up yet with ensembles etc. At least now, the models are agreeing on an event of sorts directly NYC subforum, with a period of extensive ice/snow potential interior NC- New England, mainly nw of I95. 604A/11 Appended at 755A, with the GEFS ensemble maps later in the thread. Monday - Wednesday (15-early 17): Snow-ice probably ending as rain for a large chunk of the northeast USA. Snow develops sometime Tuesday and ends by sunrise Wednesday either as ice or rain. Too early to lock in snowfall but my guess: I84 anywhere from 1" minimum to a low chance of a much as 7" for a few high terrain locations. Models still uncertain on developments but something wintry is coming. EPS is the only ensemble less than 1/4" w.e. qpf now, and this was followed by WPC on the their overnight shift which has basically nothing for I84. So uncertainty continues but from my perspective snow to ice is an 80-90% chance of occurrence for the suburbs w-n NYC, in part by the -NAO. NYC, barring BL warming, I see a pretty good chance of snow or sleet to start on the 16th. Please see attached 06z/11 GEFS ensemble 500MB for 18z/Tue-16 and 06z/Wed-17 with confluence to our north and nice short wave heading into the mid Atlantic. I like this look and presuming it holds (still spaghetti uncertainty in the members- tho I don't think south bears the brunt of there snowfall anymore except VA's highest terrain). --- 659A/10 update added here at 746A. 00z-06z/10 modeling continues all over the place. In essence, I've no significant change to this thread. Something wintry is coming. EC looks too slow and both EPS/GEFS 500mb patterns shoot the decaying Midwest short wave across the area later on the 16th. I expect that snow-sleet will overspread from the west, much of the I95 corridor from Baltimore to New Brunswick, then on the 16th while changing to rain south of I78, overspreads the remainder of the forum by late in the day. How long the snow-sleet before a change to rain (except ice se NYS/CT/extreme nw NJ)? This should be the first of two or three foreseeable wintry events opportunities for the subforum though the last two should be mostly I84 corridor (18-19, 22-23). My guess, if NYC is to get some snow, it has to be with this first opportunity (Tuesday the 16th). 00z-06z/10 ensembles used to modify the op cycles which would say, forget it for the subforum on the 15th-16th. This could be my mistake. I tend to use ensemble patterns in the longer range and focus on the ops inside of 4 days. 659A/10 --- 251-3P/9: Graphics added on with the originating post at the end of this page. Multiple 12z/9 ensembles are producing snow and ice for the NYC subforum beginning with possible scattered southeast moving cold shot snow shower dustings late Saturday or Sunday, and then a widespread light-possibly moderate wintry event 15-16. This one may even try to bridge back to another oncoming wintry event late 18-19, though with a 24 hour break later 17-18. Staying with the 15th-16th: Whether this wintry system goes the route of the most depressed GEFS, or the closer to LI, EPS and GGEM/GEPS? Something wintry continues to keep coming and while the EC had its 1-4" north of I80 on the 00z/9 cycle it now had it south of I80. This will be the first widespread wintry event of the second half of March, and as Bluewave implied, quite possibly more... this too signaled by the CFS for a few days (multiple NYC subforum snow-rain events). Graphics are the 12z/9 EPS snow (10-1), GEFS snow, GEPS snow depth returning south of I80 with a 00z-3/15 view and a 06z 3/17 view of SD 251P/9 --- 655A/9: Lot's of words follow, for the modeled proposed wintry mix solution early next week. So, the door continues open for a small wintry weather event, snow-ice to rain with very low confidence for any snow accumulation - NJ coast-NYC. Modeling continues vacillating but it appears to me it's gathering a bit of a trend for a well defined warm frontal wave e of Cape May/s of LI. (not so the 00z/9 GGEM,). It's a WAA situation over the remaining cold influx of this weekend. The weakening short wave out of the Midwest, is delayed a day so will remove (early) on the 16th from the title and drop the 14th. Whatever might have occurred the 14th might still occur, but more so late Saturday the 13th but that is a very low chance and negligible. Otherwise, ensembles are less than 2" on snow acc. Operationally the 00z/9 GFSv15-16 continue with minor ice/snow interior, while the 00z/9 EC... probably can't hold it's operational 00z/9 offering in subsequent cycles, but the EC just tells me, that that heavier single member option is still on table, as proposed a couple of days ago by multiple GFS cycles. In short: there is still a chance for snow-ice, but this is probably just your typical probably only minor event, destined mainly for the interior. This barring a reinvigoration and deepening eastward moving short wave out of the Midwest as the following short wave hurls the ridge northward behind it. Right now, 06z/9 WPC has spotty 10% chance of .25" frozen w.e. precip in the nw part of our subforum. Another way to look at this, it's a 90% chance of non-occurrence. --- 607A/8 Update: Closed low departure into midwest seems a little slower, so overall arrival may be delayed til late 15? Still looks favorable for a period of wintry qpf event anywhere in our subforum, with possibly something near the reinforcing CAA short wave Sunday, and then most likely the large scale event late Monday 15-early Tuesday 16. Think it's best to smooth out all the modeling lows and highs and see if this potential is still valid come this Wednesday morning (00/10 cycle). All ensembles (EPS, GEFS, GEPS) continue to give us some wintry qpf but just light nuisance amounts. Will revisit this on Tuesday. --- A wintry event has been on and off for our area the period of the 14th-16th (another to follow ~the 18th?). The 00z/7 EPS is driest of the ensembles but at least operationally it has a chance of flurries or a period of snow. The 00z-06z/7 GFS v15 and 16 both have snow and ice possibilities for our subforum, but primary target-duration-amounts unknown. The GEPS also has a decent qpf event coming but it's snow depth change is not enthusiastic about snow. The primary teleconnection indices are not favorable so I cannot be confident of snow NYC-LI but I do think we will see a ~1/4" of freezing-frozen precip into at least a portion of the NYC subforum by Tuesday morning the 16th. (that could be snow-ice combo or just 3" of snow). The primary event is centered on Monday the 15th. Typical late season caveats apply including light precip during the daylight hours (spring forward 1 hour on Sunday 14th to EDT) being almost useless for road impacts except wet road slow downs. Alot of this will depend on strength of the high over Quebec and how cold the boundary layer. This is basically a D8 outlook: So I dont want to encourage diving deep into snow dreams but something wintry is coming. Whether it's only I84 high terrain or more encompassing is tbd. This will probably garner some attention in the coming days. One graphic to demonstrate the emerging low in the Midwest 12z/14 with the confluence zone. (649A/7)
  19. Monday morning March 1 625AM Update: Good to see the sleet obs yesterday in our distant nw suburbs. Below restates what is obviously modeled and discussed in prior days updates: I moved the timing up an hour and changed the title to add OBS-NOWCAST as well. Will have summary maps of rain, any snowfall, and possibly wind gusts 45+ in tomorrow's (Tuesday) 10AM wrapup-review. Tonight 7PM/1 -3AM/2. Turning sharply colder with bands of flurries and snow showers causing a few areas of hazardous travel as temps fall from near freezing at 7PM to between 5 and 15 above by dawn Tuesday I84, and near 20 NYC, along with gusty northwest winds 35-45 MPH and wind chill down just below zero. Most areas only flurries, but a half inch of snow is possible a few locations ne PA, extreme nw NJ and especially se NYS, CT and maybe even e LI. A wind advisory is posted with NYC wind chill close to zero at sunrise Tuesday. ---- 650A Sunday/28: Ttile dropped snow from the snow to rain scenario. Significant 21 hour rainfall (1/2" I84 to 3/4-1.5" NJ/LI) this afternoon into Monday mid morning with snowmelt but not enough for a problem. Could see the need for something water related a part of urban ne NJ by Monday morning? Dense fog possible tonight with mild moist air over chilly ground. I think there will be spotty icing highest peaks of the Poconos/Catskills/Litchfield Hills this afternoon-tonight but no significant treated road problem. Small chance that rain ends as wet snow forenoon Monday I84 high terrain with little or no impact, if it does end as snow. Monday evening from roughly 8P -4A Tuesday, flurries likely to near NYC with a band or two of snow squalls CT/NYS/ne PA and possibly extreme nw NJ that could coat roads with a hazardous 1/2" accumulation in 30 minutes, along with gusty northwest winds to near 45 MPH, a few minutes of reduced visibility under 1/2mile and icy roads due to temps plummeting from near freezing at 8PM to the teens by dawn Tuesday (20-22F NYC?) and wind chill near zero CT/NYS/PA. We'll see if the models back off but from what i can tell, the early GFS op (V15) has been onto this from many days ago, much more so than any other model. NYC either no snow or a Trace of flurries. Some of the modeling suggests a band of squalls crosses from CT through e LI later Monday night. --- 655A Saturday/27: Coming to the end of this thread... that may end with a noticeable bang. Definitely a significant rainfall (1/2"or more) Sunday into Monday morning with snowmelt but not enough for a problem. Dense fog possible Sunday night with mild moist air over chilly ground. Chance that rain ends as wet snow forenoon Monday I84 high terrain with minuscule impact. However, Monday evening from roughly 8P -4A Tuesday, flurries likely to near NYC with a band or two of snow squalls CT/NYS/ne PA and possibly extreme nw NJ that could coat roads with a hazardous 1/2-1" accumulation in an hours time, along with gusty northwest winds to near 45 MPH, a few minutes of reduced visibility under 1/2mile and icy roads due to temps plummeting from near freezing at 8PM to the teens by dawn Tuesday (20-22F NYC?) and wind chill near zero CT/NYS/PA. We'll see if the models back off but from what i can tell, the early GFS op (V15) has been onto this from many days ago, much more so than any other model. Bluewave detailed elsewhere in the March thread. --- Good Friday morning everyone, Feb 26: Focus is mainly the I84 corridor. The Adirondacks are reserved for the last pgh. 1201AM-10AM Saturday (27th). A 1-4 hour period of showery wet snow-sleet will probably occur from the Baltimore area northward across the I-84 corridor early Saturday. There even could be spotty freezing rain? Minor-short duration impact, at worst, reserved primarily higher terrain where an inch or 2 is possible in the Poconos. Elsewhere for the I84 corridor, inclusive of nw NJ, expect a Trace-3/4"; Baltimore-Phildelphia urban centers a Trace. A quick change to rain occurs shortly after onset, except that change to rain in the Poconos and northwest hills of CT may not occur til ~ 10AM Saturday. Melting all surfaces once the change to rain has occurred. Most may not notice the snow if sleeping. Late Sunday the 28th-Monday March 1: I84 corridor. Uncertain but probably not a significant problem. Complex rain (spotty ice) possibly end as snow event. Any icy weather Sunday evening the 28th is reserved for the Poconos. Precipitation may end briefly as snow the rest of I84 corridor Monday morning March 1? So far, models say proceed with normal life with significant wintry weather unlikely. Monday night March 1 I-84 corridor---near midnight: A strong cold frontal passage may be accompanied by a dusting to 1/2" of snow. If this occurs, the sudden drop in temps with the snowfall would make it slippery. March 3-6: Uncertain modeling continues to suggest a wintry event that may include several inches of hazardous snow for the I84 corridor northward? Some models have no storm, so nothing to be sure of. Adirondacks: Please follow local forecasts: snow showers or flurries this morning. A period of snow Saturday changes to rain. A period of rain or ice is possible Sunday. Then, a refreshing of accumulative snow late Monday followed by a polar plunge Monday evening. March 3-6--- uncertain but seems like a period of snow in there somewhere. The second week of March, especially after the 7th... looks rather mild. 615A/26 Friday 517PM/26 update: 517PM Friday: seems to be getting slightly more interesting for ice and snow distant nw-ne suburbs. First: GFS v15 looks like, (barring a complete fade within 4 days) the winner regarding the intensity of this cold shot Monday night. Second: Unclear to me whether it warms much above freezing high terrain near I84 Sunday and I can see smidge of ice there. Third: Chance of dense snow eating fog late Sunday? Fourth: Modeling from both the GFS V15 and 16 has started showing more minor snow shower/flurry action Monday, on the backside of Sundays rain (and dense fog by night?). And 18z/26 GFS modeling is moving flurries down to near LI sound later Monday night with the strong polar cold front that looks like it may have gusts near 45 MPH drilling sharply colder temps into NYC. Will revisit Sunday morning. --- Friday 638AM update: Am still not convinced that this event will be insignificant but it's heading to a possibly wrongs-wasted thread. We do know it's going to rain and potentially pretty hard for a time on Sunday with precipitation lingering into Monday morning. Evolution has not yet permitted cold enough air to return, allowing for precip to change to snow Monday. Of concern to all who favor the GFSv16 implementation, is the still far different modeling between the V16 and the current operational V15. V15 in my opinion seems to have a pretty good chance of prevailing with it's polar cold frontal passage Monday night, flurries or snow showers possible down to NYC with plunging temps well down into the 20s in NYC (maybe ~22?). Meanwhile late Sunday the 28th-Monday March 1: I84 corridor. Uncertain but probably not a significant problem. Complex rain (spotty ice) possibly end as snow event. Any icy weather Sunday evening the 28th is reserved for the Poconos. Precipitation may end briefly as snow the rest of I84 corridor Monday morning March 1? So far, models say proceed with normal life with significant wintry weather unlikely. --- Thursday morning (25) 659AM update: Modeling and WPC is coming up on qpf for Sunday and there may be lingering Monday morning at the least. I have not crossed this thread off as a bust for the I84 corridor. No excuses. I still think it's on the boards and what I do think I know is that decent qpf is coming the 28th. Late Sunday the 28th-Monday March 1: I84 corridor. Uncertain but probably not a significant problem. A complex rain (spotty ice) possibly change to snow event. Any wintry weather Sunday evening the 28th is reserved for the Poconos. It could spread across the rest of I84 corridor by Monday morning March 1, but for now models say proceed with normal life. As you know, GFS modeling is drifting away from its excessive cold outbreak Monday night and leaves the door open for a little more than meets the eye (so far). I might be completely wrong for this period, regarding a wintry event occurrence but the door for me, is not yet closed. --- Wednesday morning 655 AM update: Title remains unchanged. May need to add a bit of ice for the interior in future reviews. Multiple model ensemble reviews of the 00z/24 cycle and 06z/24 GFS and V16 op reviews. Late Sunday the 28th-Monday March 1: I84 corridor. Still uncertain. A complex potential significant rain to snow event. Any wintry weather Sunday evening the 28th is reserved for the Poconos. It could spread across the rest of I84 corridor by Monday morning March 1 with significant hazardous high terrain accumulations of several inches I84 itself northward, while much less impact in the valleys below 700 feet elevation (Hartford, Poughkeepsie, Scranton). A shot of notably cold air follows Monday night (but not the GFS op ferocity which doesn't have much support). This for me is the 00z/24 consensus from NAEFS and 06/24 V16. Definitely not buying the GFS powerful cold shot preempting an event. I could be wrong but I see enough cold air seeping into the backside of whatever comes out of the Ohio Valley to make for a snow risk. It could even snow down to LI/I78 at the tail end (low chance for now, but a window that needs to remain open). It's complex and details remain tbd. It's possible I've read too much into this thread?? Considerations include WPC continues rather dry and very little wintry weather risk. --- 624A/23 - Tuesday: Incorporates modeling of ensembles through 00z/23, and op models through 06z/23. Maintain patience. A significant event is probably coming including some snow for I84 and possibly to NYC's immediate n/w suburbs. EPS/GEFS trending a fairly significant decline in AO/NAO first couple of days in March (think this an EPS concession to the GEFS, as i recall). GEFS has significant snow for the Virginias on the 2nd. That is a sign something is coming, with latitude axis of snowfall in doubt. I favor further north, per NAEFS. Also, the 06z/23 GFS op not given any weight in my thinking since its prediction for the NYC 1000-500MB thickness 06z/2 is 240 m less than the V16. (504 op vs V16 528 for NYC). Sensitivity between northern southern stream interactions is probably messing up solutions and so uncertainty. It either snows a bit late 28, or what i think is more likely is some snow late March 1-morning 2. EC wants to snow the 3rd. Therefore, no change in thread. --- 646A/22: May extend the title to 3P March 2 in the updated post tomorrow morning, otherwise, despite some dry modeling, I think we're on track for a significant event, some of it wintry, especially I84 corridor. Details TBD but it looks to me like a warmer wet prelim event late 28-early March 1, then some cooling and a change to snow from north to south late March 1 or early March 2. If its the standard CFP with low north of our forum, then no snow LI, but if it's two waves of low pressure, then the fun of the challenging forecast. I can definitely see 4" of snow in the northwest part of the forum for this complicated event. Not saying 4" will happen but definitely potential. --- 550A/21: No change to thread (for me). Model variability. By and large looks too warm for more than 1" of snow/sleet NYC-LI-s of I78, if any at all. Modeling does have an option for heavy qpf, snow/sleet/freezing rain to rain, end as snow especially I84 corridor. Not saying that will happen, but I think that option is realistic instead of the all warm-wet Great Lakes inside runner scenario. It's complicated and if necessary in a day or two may need to change the primary end date to March 2, as optioned in the initial thread. Also, for now no flood threat due to snowmelt/qpf, if that warm heavy qpf option comes to pass as the primary reality. That flood threat insert for me, has to wait 3 more days before throwing in the towel on my primary concern for wintry elements. Finally, that closed low option continues (06z/21 V15 ballistic, V16 not). Will monitor successive GEFS 6 hour member cycles as seen on http://www.meteo.psu.edu/~fxg1/ENSHGTAVGNH_0z/ensloopmref.html Any questions and I can guide us thru this. Just use your cursor to slide over the hours from L to R and not only monitor the mean, but the spaghetti, which for me is crucial to understanding future model options. ---- 330P/20: 12z/20 EPS GEFS diverge with the Canadian GEPS favoring too warm for snow I80 south but that can change in 9 days. What does seem apparent is that there will be strong WAA into the top of the ridge, which can allow snow at warmer than expected 1000-500MB thicknesses due to marginal column temp for phase change to rain. Also, there have been some GEFS members trying to close off a low over the forum (too little-too late & too far north?). While that type of deepening is not predominant now, it seems worthy of monitoring daily trends. One of my concerns is that LR modeling in the 6-10 day range has yielded colder results recently, than what we would have thought beyond D5. 12z/20 modeling also indicates a healthy qpf event of 1/2 to possibly 1". This event is focused on the 28th-1st, but not impossible to see it begin late 27 or end on Mar 2. . Only 1 graphic for a couple of days.
  20. Friday 525PM: Made this a combined obs-nowcast minor event thread. 509PM: Possibly my last update for the evening. Other than the low levels being a little too warm, it's conceivable that snow will be seen to within about 10 miles of the NJT late tonight with minor (trace to 2") accumulations as previously discussed ne PA/nw NJ/se NYS and I84 northward in CT. No new obs thread for this for many reasons, including minor 1-4 hour wintry event, occurring during the night when many will be sleeping and many areas melting as it hits the ground. --- Friday morning 625 AM update: 1201AM-10AM Saturday (27th). Not anticipating an obs thread since the percentage of members involved (seeing snow/sleet) looks to be rather small. Just tag it on here, whatever might occur. A 1-4 hour period of showery wet snow-sleet will probably occur across the I-84 corridor early Saturday inclusive of nw NJ, ne PA northeastward. There even could be spotty freezing rain? Minor-short duration impact, at worst, reserved primarily higher terrain where an inch or 2 is possible in the Poconos. Elsewhere for the I84 corridor, inclusive of nw NJ, expect a Trace-3/4"; A quick change to rain occurs shortly after onset, except that change to rain in the Poconos and northwest hills of CT may not occur til ~ 10AM Saturday. Melting all surfaces once the change to rain has occurred. Most may not notice the snow if sleeping. ---- 730A/Thursday the 25th: As a friend said yesterday, winter's back is broken. 3AM - 10AM Saturday (27th), a 1-4 hour period of wet snow will probably occur across the I-84 corridor west of Hartford early Saturday. Possible minor short duration impact at worst, reserved primarily higher terrain where an inch or 2 is possible before a change to rain around or after 10AM Saturday and then melting all surfaces. Most may not notice the snow if sleeping. No obs thread, unless modeling shifts a little closer to NYC (within 10 miles). --- Wednesday morning Feb 24 640A update: Updated title to only Saturday morning the 27th, and mainly interior only. Have posted nw suburbs thread since this nuisance negligible event appears focused for only high terrain of an inch or so Saturday morning before a change to rain/melting. Might provide a bit of a minor slippery slushy hazard untreated surfaces before sunrise Saturday nw of I287, i.e. nw NJ hills/ne PA Poconos and interior se NYS toward the Catskills, and possibly Litchfield County, northern Fairfield County CT. Small possibility of an obs thread if snow occurs as some modeling tries to do to within 10 miles of NYC, but for now... not counting on that thread. This one would suffice, if this does minor snow occurs. Probably good to monitor NAM/RGEM cycles for consistent trends-if any. And the GFSv16 too, if you have access thru Pivatol Weather. V16 may be available elsewhere? If so, please share. COD? ---- 543A/23 -Tuesday. Incorporated 00z/23 ensembles and modeling through 06z/23... suggests maintaining some vigilance for a period of Saturday morning snow, probably Trace- as much 4" for the I84 corridor Saturday morning. Multiple modeling has that option. LI/NYC probably rain but may briefly start as wet snow? WPC is trying to keep us dry but i don't think that will work. My concern for a minor snow event are how close to NYC (mainly w of 287?) or possibly a little closer. There will have been a freshening of the cold prior to this pulse of WAA which will be reflected with a small mid Atlantic coastal low. Want to wait this out til the morning of the 24th to be more definitive. Modeling is all over the place and thermal profiles marginal, as so many. No ensemble prob graphic since WPC has little or no qpf (less than 0.10"). --- 628A/22: Despite some dry forecasts, my confidence in another snow event is categorical interior and likely coasts inclusive of LI. Have changed the title to Noon Friday (and extended from 6A Sat to Noon Saturday) and simplified the wording. Most of this should be Friday night-Saturday morning. I expect this to be a hazardous event on all untreated surfaces by sunrise Saturday (interior). Am even a little uneasy on the previous low chance >.25" in the title. For now , I see a 1 to possibly 6" snow event for the forum with highest totals, whatever they are, in the interior high terrain-probably ne PA/extreme nw NJ/se NYS Orange County northward. 00z/22 EC changes to rain everywhere, whereas the GFSV16 is further south and ends briefly as rain midday Saturday. Nice competition between the EC/V6 op runs. GGEM sides with the EC though seems slightly colder than the EC. My initial 20th post concerns for Thursday the 25th, seems to have evaporated due to dominance of high pressure arriving behind the southward proceeding cold front. One other note i should add: NAEFS says EC probably has a better handle than the colder model solutions. I'm not buying the NAEFS warmth for the interior, at least not at this time. This will be a big test of the GFSv16, soon to be implemented as a replacement for the GFS op (V15). --- 627A/21: WPC continues dry but as you probably saw, the 06z/21 GFS V15-16 have turned northeast. This is a complicated situation with other snow/ice options. First, it's not clear to me that something cant happen here late Thursday-Friday (25-26). The Saturday morning (27 option) may force me to adjust the window of opportunity into the 27th. That part is associated with a subtle trailing shortwave moving ENE from the Ohio Valley (WAA) behind the initial primary short wave passage of the 26th. That subtle short wave induces low pressure newd to the Mid Atlantic coast with a possible inverted trough back to the Catskills. What's it mean for NYC? Possibly a period of snow or sleet? with a better chance of snow or sleet inside of I95. Does it change to rain in the interior if it does come north- too early to know. First, I think we need this option to stick, so to speak, and then can venture to discuss this minor or moderate event? Lets give this 24 hour more of cycles and then try to isolate the wintry problem, if it still exists Monday morning, --- 301P/20: While 12z/20 GEFS guidance was delayed for full review (and therefore NAEFS), there is potential for a light or even moderate fast moving (east or east northeast) precip event. Depends in part whether the primary low crosses the St Lawrence Valley, or whether the front sags south of the forum with a wave of low pressure scooting eastward on it, as a fairly strong wave heads east from the Great Lakes. Ensembles at this writing are not favorable for much of an event but individual models for the past 2 days have proposed an advisory snow either in our forum, or south of us, across the Virginias/Delmarva. The latest 18z/20 WPC guidance basically has no qpf in our forum for this event, so it could easily be a bust. I think some wintry precip will happen here, but could be 100% wrong. Let's leave the door open for a couple of days and see if this can target a portion of our area with an inch or more of snow. If snow does occur but only I84 corridor, then there won't be an obs thread (fewer members). TBD. .
  21. Good Tuesday morning all, Expect a period of snow showers in the nw-ne suburbs toward midday. Elsewhere for NYC/LI & s of I-78, rain or possibly rain/mixed snow showers early this afternoon. No accumulation NYC CP eastward and southward, however 0.1-0.7" possible in a few hilly areas well northwest and north of the city. Essentially harmless, with probably no street hazard, other than what one might expect in a rain shower. This is associated with a strong wave passage. mPing should be somewhat active between 10A-4P. No graphics today with the graphics below from 2/22. 528A/23 -- Today (22): Advisories posted just w and n of I-95 for a 5 hour period of occasionally heavy wet snow, while snow NYC and possibly all of the forum coasts during midday changes to rain. Exception southern Ocean County - which may be all rain. Snowfall rates of 1-1.5"/hour anticipated for portions of NJ will quickly make treated roads slippery for a time. Isolated ~5" possible part of NJ near and north of I78 with a general 2-4" accumulation in the advisory area though 4" possibly less likely in NYS/CT. This band may spawn isolated thunder in NJ/LI as it models convective in nature. Expect the first heavy burst within 1 hour of onset, then a slight relax followed by another heavy burst, then on the wane it's last two hours. Begins NJ/ne PA/se NYS 10A-NOON, NYC/CT Noon-1P,. Ends about 5 hours after onset. . Snow in NYC CP possible until 2P where anticipate anywhere from 0.2 to 1.4" there , dependent on temps/how quick it changes. Even a slight coating possible all of the forum coasts. Tuesday: Combined Tuesday in this thread only because it's a top 8 February and many members even out to eastern LI should see some sort of snow showers for an hour or two (may be more accumulation e LI Tuesday than today). Snow showers possibly mixed with rain on LI. Many locations Tuesday should receive 0.1 to as much as 0.5" new snow by ~1PM... the showery occurrence primarily during midday. Attached the 00z/22 HPC HREF, the 06z/22 NAM anticipated base snowfall and the NWS regional deterministic snowfall graphic.
  22. 612A/21: The answer to the thread is yes. Questions seem to be centered on bullseye convective snowfall of 3" in 3 hours...it's location, and whether NYC can have enough snow fall between Noon and 3PM to cool the temp enough to stick to the snowboard in CP? Modeling differs, and snowmelt during the noon hour could preclude measuring CP but an inch is an option even to BWI/PHL/NYC. Not saying that it will happen in those urban centers, but it's possible and then also capturing the observed snowfall via a report. Meanwhile, I see this as a shorter term advisory issuance for portions of the hilly terrain subforum, primarily e pA/w NJ (maybe se NYS/Litchfield Hills?) to handle the short term rapidly changing road conditions in a 3-5 hour period of snow there with embedded 1"/hr snowfall rate. Heaviest for now targets somewhere from MD into NJ/e PA. That may become a short fuse convective snowfall consideration. Isolated 5" possible somewhere e PA/w NJ? General snowfall amounts se NYS/CT less than w NJ/ePA but still 1 to possibly 3". Will probably begin an obs thread Monday morning at 5A if it still looks like NYC members will see some wet snow to start. (I didn't mention, that a flurry is possible prior to sunrise Monday, but that flurry is not the primary concern). Four graphics added: the 09z/21 NWS deterministic snowfall, the 09z WPC ensemble chance of 1+" of snow Monday, and 4+" and the 00z/21 HPC HREF (high resolution ensemble snowfall). 718A/20: Dropped the 24th as the window of opportunity focuses on the 22nd, but with the second short wave possibly depositng a minor amount of nuisance snow showers on Tuesday. Timing has delayed slightly in the modeling to essentially a 10A-4P time from on Monday, with melting in NYC/LI compromising measurable chances but to I95, there is a small chance of 1" accums in a somewhat convective band of snow. 528A/19: Drpped Sunday Feb 21 from the topic title. This event may be running slightly slower than earlier projections which reduces the chance of any accumulation NYC-LI but not a complete zero chance there. Otherwise, modeling continues to like high terrain snowfall of 1-4", even an inch possible to just inland from I95 Monday morning the 22nd, changing to band of heavy rain showers for LI/s CT during the afternoon. Have not eliminated the 23rd/24thfrom the topic because of the trailing second short wave which may induce scattered snow-rain showers into the forum. Primary accumulation risk appears to be the 22nd. 518-32A/18: Just rain for much of the forum (trace of snow at the start?), except high terrain nw edge which remains with potential for wet snowfall of 1-4" in a few hours. Modeling is trending a little warmer and no expectations of low s of the forum until too late, if then. Also, no plan for a separate OBS thread for this probable high terrain only-extreme northwest part of the forum thread (I84 vicinity), barring a faster early morning onset of the primary qpf which would then allow snow in NYC. This NYC snow option is not currently expected due to 00z-06z/18 warmer boundary layer temp modeling. 605A/17: Continues on the books. One graphic added. Appears some sort of secondary gets going s of LI, maybe too late to shut off boundary layer warming but ensembles and multiple op modeling have some potential for 3"+, mainly high terrain. Will adjust the window of opportunity in a day or two, once am sure. 533A/16: Modeling trying for a T-2" in the I78 northward portion of the forum around the 22nd. Not impossible to see a burst of WAA snow Monday morning the 22nd (how much melts before the 18z ob) and a CAA shorter period of snow the 24th. No low centers south of LI at this time. 635A/15... changed description to yesterdays intended will the LOW be south Added one graphic showing the GEFS trend from then 00z/15 modeling for a digging amplifying short wave through the Great Lakes ~the 23rd-24th. Still north but modeling has a little snow for the forum. Could be a dud but we'll see. ~230P/14 initial: Since members are already posting beyond what will be a difficult week of weather in our NYC subforum (15-19), have offered a 4 day window for one of the two well defined short Aleutian short waves to continue some of the modelings signals, dropping a few inches of snow in our area. Modeling (12z/14 EPS, EC and GFSv16 op) tends to favor the higher terrain of the I84 corridor. It is getting later in the winter so odds may not favor much, if anything, in NYC. At this point, if this fails, I think it will fail warmer and to our north since 50/50 blocking is northward transiting, allowing for warming aloft down here. Will update this topic after we get through the morning of the 16th, including tightening the window of opportunity (if it still remains?) as we draw closer to T0, inside of 6 days.
  23. 515A/19: Intermittent event continues and precip intensification gradually changes freezing rain/freezing drizzle sleet near I95 eastward to snow. Ending time still the same, this afternoon sometime ne PA/nw NJ/se NYS and the remainder sometime this evening-early tonight. Between 7AM-ending time, I expect a general base 1/2" new throughout the forum after 7am with possibly as much as 3" , the heaviest seeming to be near NYC into CT per a decent band developing this morning-midday, and possibly a nice hour of closing snow this evening. Easy melting process on pavement expected during the midday-afternoon hours where temps above 25F and when snow lessens it's intensity. Manageable but fun for us. 450AM/18: overall no change in expectations. Might get started an hour or so slower but already flurries or steady light snow have occurred se NYS, ne PA, CT, far nw NJ. See latest NWS products and your own judgement. 548AM added the 4AM NWS regional snowfall expectation that went into their early morning products. An overall manageable 24-36 hour wintry precipitation episode will probably see snow change to a mixed bag in NJ/LI, with even a bit of rain possible for a time eastern LI and the NJ coast. Snow should begin in seNYS/NJ/NYC between 2AM and 7AM Thursday and by 9AM elsewhere. It should snow moderately for a time sometime between 9AM and 4PM Thursday before probably transitioning to mixed precipitation or even quitting for a time in NJ/LI toward Thursday evening. Precipitation may intensify again as it probably changes back to snow everywhere on Friday and then gradually ends from west to east during the afternoon, or early Friday night. Graphics are the 21z/17 NWS ensemble 48 hour prob for 8"+ of snow, 4"+, the 12z/17 SPC HREF snowfall ending 00z/19 = 7PM Thursday, the 5PM/17 actual NWS regional deterministic (approximate) snowfall forecast and the 21z/17 WPC ensemble prob of .01" freezing rain. Thursday afternoon into Friday morning. Please contribute as needed.
  24. 554A/17: Topic headlines adjusted from the original late last week to the snowier wintry solution. A burst of moderate to briefly heavy snow Thursday, begins lightly between midnight and 6AM (OBS-NOWCAST thread will be started this evening) Thursday much of the area, though it may delay a bit to the daylight hours north of I84. QPF etc has decreased since originally threaded. Modeling allows sleet/freezing rain to get involved near the Thursday evening rush hour and eventually back to manageable, possibly intermittent snow on Friday. Some modeling has a decent burst of snow Friday. ~Half a foot or more seems likely for much of the area with sleet/freezing rain (even maybe eventually even a bit of rain e LI) limiting the risk of 6" south of I78 and possibly LI as well. Graphics added are WPC 09z ensemble chance of 8"+, chance of .01 freezing rain for the periods indicated (note ensemble chance of 8+ has higher chances southwest of Harrisburg but that includes time not shown in this depiction) and the NWS regional snow forecast. 517A/16: A nice solution coming (overall colder and snowier than what modeling was generally offering Friday the 12th) with a range of accumulations of 1" to possibly as much as a foot in the upper high end scenario. Thursday's evenings commute should be snowy for much of the area and see delays, as it readies for a possible change to ice Near I78-LI (rain far south part of the subforum) and then ends Friday, most of it done by sunrise Friday (but with early morning delays/cancels). Too early for me to be sure for the NYC/LI/NNJ membership but plenty of modeling close to half a foot. A watch/warnable snow-ice event seems to be coming for a portion of NYC subforum,. IFFFFF NYC were to report half a foot, that would place NYC in the top 5 snowiest February's. This coming snow-sleet, whatever, should rejuvenate snow depth , and maybe allow half a foot or more for much of the area into Monday Feb 22. One WPC graphic added: the 24 hour prob of 2" of snow by 7P Thursday. --- 625A/15: Adding the ~5z/15 NWS prob of 3+" snow graphic. Otherwise, variable modeling with it appears to me a slightly colder trend, but still any snow should change to sleet/freezing rain for a time, and maybe just rain LI s of I78. Very uncertain but NWS probs are very high just north and west of NYC for 3"+. We'll see how it works out. 525AM Sunday the 14th- Valentines Day! This event still looks interesting for snow lovers, despite the warm GFS OP. This is a prelim update for an event 5 days away. Definitely Advisory minimum potential, especially interior and possible Watch-Warning material interior part of the forum north of I78. Early guess on modeling...a range of 1/2-5" of snow-sleet Thursday before a change to ice North of I78 and just rain LI and south of I78 Thursday evening with rain most of the area for a short time Friday morning. Snow and ice ne PA/nw NJ se NYS/n CT. How much of each phase unknown. May add another graphic or two by the 915AM full update of this topic. Here's the NWS ensemble prob of 3+" of snow Thursday...that light blue is 70% up there by I84. 520PM Saturday: EPS drifting north for Friday morning so front end snow/ice goes to rain, possibly north of I84 Fri AM? Still... with all the modeled qpf, the 806AM water snow equivalent weight concerns, and definitely gutter ice water damming/roof leakage possibilities. Five to 6 days away. 806AM Saturday the 13th update: Ensembles differ (GEFS far northwest with a primary into the e Great Lakes), while the 00z/13 EPS further southeast with a coastal and therefore colder. NAEFS is in the middle and says snow or ice to start the 18th, changing to rain before ending on the 19th. I won't add many graphics since its similar to yesterday. My concern is another ice storm for the I84 high terrain corridor and snow pack water equivalent weight increasing as well as jammed snow and ice laden gutters. 00z/13 EPS-EC not to worry so much as it likes less qpf and more snow down at least to I84. What I think we all know... delays and cancels coming for Thursday, at least the region close to the nw side of I95 and northward. I added the Thursday-Friday 12/8-19 total qpf graphic generated by the NWS early this morning. It might be a bit heavy and too far north but uncertainty. As of this starter thread it appears the region along and south of I80 including LI-NYC would have mostly rain but possibly a front end burst of snow or ice. Presuming the cold source over New England remains intact at the time of late next weeks arrival of this large amplitude central USA trough, there exists potential of around 1/4" of glaze or more, for at least the I84 corridor high terrain (especially northeast-east slopes), IF there is only a little sleet or snow to start. Longer duration of any snow or sleet (ice pellets) at the start, would reduce the risk of advisory or even warnable amounts of icing. There is even some modeling suggesting enough cooling toward the departure of storm that precip might end as snow. Finally the long shot (low probability-wishcast?) this far in advance is that this system comes out in two pieces, one ~the 18th...colder and bit snowier, and a second delayed piece of energy late 19-20, possibly redeveloping a little further south than now modeled with a colder solution. For now, it looks like a period or two of heavy rain LI/NJ coast and a period or two of mixed heavy precipitation nw of I-95, especially the I-84 corridor. EPS modeling of snowfall has been emphasizing PA-NYS central-northern New England for heavy snowfall (or ice) with the gradient edge in our NYC subforum meaning greater chances of snowfall ice accumulation error. This could become a major storm of one sort or another for our subforum. It will be of interest to monitor the water equivalent in the remaining snowpack the morning of the Feb 20. If that snowpack is with 4" of water equivalent on some widespan flat roofs and or ice/snow clogged gutters, we might be seeing some associated damage developing? No science from myself on this.
  25. 859AM/14: The GGEM/RGEM are going to win this Monday battle of no precip vs freezing precip occurring. The 06z EC and lesser so GFS, are capitulating to a two part event beginning Monday morning. The 06Z EC gets this going pretty fast before dawn Monday. I'll get the OBS thread going around 9PM tonight... and to keep it simple, will combine both the front end Monday morning with the primary Monday afternoon-Tuesday morning event. Problems for us will be developing. Added NWS 09z/14 ensembles for .10 glaze and .25" glaze (threshold to begin power outages, the grow much larger when 0.50 glaze ) and added the 5AM view of NWS snowfall expected by Tuesday evening. 513 AM/14 placeholder- will fully update by 915A today. It's Valentines Day. Hope all is going well. Rain LI for this event- some of it heavy. Topic headline changed a bit to further add some detail. Otherwise, Certainly an Advisory event coming inside of I-95 Monday-Tuesday morning. There is a low probability of Watch-Warning verification ne PA/nwNJ/se NYS and N CT part of the forum for ice but questionalbe we can get to 1/2" damaging ice qualifying for a warning. I suspect there will be some damage and power outages if the furnace (borrowed from others on the forum) RGEM continues this cold but possibly below warning criteria. The GFS is warm tho its 06z version looks slightly colder. The GFSV16 is colder than it's soon outgoing GFS op and it holds to the 0.2-0.4" FRAM ice accretion for the event, which begins sometime Monday and ends midday Tuesday. I still don't have a good feel for Monday but modeling is trending to agree with prior versions(from at least back to 00z/13) of the GGEM/RGEM that our untreated surfaces problems begin Monday during the day, especially afternoon. Need more time to assess. My feeling is the leftover advisory from this morning complicated multiple confusing headlines for the NWS and the idea, take one event at a time. More later with graphics. -- 745AM Saturday the 13th update: Good Saturday morning everyone - Feb 13. Adjusted topic headline slightly to include potential for an ice storm across the high terrain, and timing, tho w uncertainty. This will more easily allow an eventual OBS thread bridge back to Monday afternoon, if needed that early. The GGEM/RGEM for Monday: I dont have an answer. Some modeling yes, others NO. Something to watch. Right now am advising friends its okay to travel midday Monday along I84 due to milder temps near freezing but this 00z-06z/13 GGEM/RGEM is a concern. Late Monday the 15th-Tue the 16th: a significant advisable-warnable extensive ice event coming to the I84 corridor where it may transition to snow. This is mostly ice and I foresee-expect extensive delays Tuesday morning, and some cancels. Unsure whether this is mostly sleet or combined sleet-freezing rain. Might even have a bit of snow with this, just north of I84 where I could see several inches in this mix. Just too much uncertainty for me to know. For NYC-I95 so problematic am not going to attempt to detail... it varies by the modeling and cycle but looks like a transition to rain LI and NJ coast for sure on the 16th. BUT... stay tuned if wind stays mostly NNE. What I think I'm seeing is the GGEM-G=RGEM drift colder early this coming week. All yours... will be back around 5P to this thread. Added one NWS 09z/13 NWS ensemble graphic: the risk of icing Monday, especially at night. This tells me a problem is coming. ---- 854AM Friday the 12th: Have no changes to the Thursday 11th updated post. Added the WPC overnight prob for 3"+ of snow which favors north of Li and lots of zr/ip/r for LI and the NJ coast. 830AM Thursday the 11th: Have not added ice storm for the 18th and extended the thread into the 19th, but will probably do that tomorrow morning the 12th after 1 more day of cycles. I think ice storm warning is a possibility for the 18th-19th in parts of the higher terrain I84 corridor but far too early to highlight, since it's also possible that the modeling is too warm-allowing for more sleet/snow - future modeling to determine. Right now it's complex with predominant ice (ice to rain LI) but may end as snow everywhere? So far no sign of a closed low slowing things any further so have to go with what we see. NAEFS turns interestingly cold in the 1000-500MBthickness to wrap this event up on the 19th. Late 15-early 17... i like a colder solution than generally modeled tho not necessarily buying into the 06z GFS op. I think NYC will see some snow acc but ice could eventually get involved NJ/LI. Modeling is pretty cold at the surface. This will be a moderate event. Advisory event or possibly even a warning event for some of the subforum. Added NWS overnight prob of 3+" of snow Tuesday the 16th..favoring I84. Also the 06z/11 GEFS with the blue line the op run and the black the mean. You see ther spread in membership. Includes qpf, 850T, 2meter T and snowfall. I'd play the snowfall low key right now, so much spread mainly due to ptype. Definitely warmer on the 18th-19th. ---- 255 PM Wednesday (10th update): No overall change. Think the 14th is probably all snow or just a touch of rain extreme southeast? By 6PM Valentines night, I think the Feb totals in NYC will have increased 1.5-4" from this mornings 19.9 value...to place the Feb NYC ranking near #11. No guarantees but I think the Valentines (late 13th-14th) event is mostly snow and generally light. I still like 1-4" as a basic starting point. Did see the GFS trying to split NYC with nothing, but relying a little more on the GGEM and ensembles for this assessment. Tuesday the 16th: I know there is potential for ice all the way up to I84... but the front end thump of snow should be decent and I could see this event remaining all snow far nw NJ to nw CT and 6+ continues to be what I'm thinking, at least along and north of I84. Axis of heaviest snow ice is debatable as is northward ice encroachment but overall this looks to be a fairly cold event. Thursday the 18th into early 19th: Challenging... at first glance looks warm, but if you look at the GEFS and some previous operational runs, one can envision a closed 500MB low developing in TN/MO/ARK and then from there??? slower, so that we have a somewhat colder subdued event the 18th and may have to wait for a big qpf event til late 19th or 20th (outside this thread), instead of as progressive as now generally modeled. One question i would have... would that closed low be able to translate newd the eastern Great Lakes or... across the Mid Atlantic? Lots of speculation on my part, and maybe it just comes out bodily as now implied (18-19)? Just bringing up the complexities I can see. No matter, more ice/snow/rain...take your pick and for now I would have to favor rain LI/coastal NJ or brief snow-ice to rain there while, interior?? maybe lots of ice? ------- 808A Wednesday (10th) update: No overall change. This is the thread that dove tails with the 11th-13th thread. The 13th event, however it evolves will probably end up with a decent amount of snow on the morning of the 14th and so am continuing the widespread 1-4" idea (even LI-NAEFS rather cold there). Modeling has trended a little colder (blocking) but not necessarily a big coastal, but some WAA snow. 16th: looking more significant than the 14th. I think it's still cold enough for a front end thump of snow. Ice/rain may eventually get involved NJ/LI but where all snow, seems like a decent chance of 6+, probably I84 corridor, but even LI has a chance of at least a light snowfall prior to a phase change. 18th: may be the biggest qpf event of all 3 with a more southerly track of the trough and a GMEX scoop of RH (18th-early 19th?)BUT, that one seems somewhat warmer... so more problematic for maintaining entire wintry elements, but possible. The good news: IFFFFF this one is pretty big and more of a southern streamer, there is a "chance" it will re-energize the block near 50-50 for subsequent events after the 21st. ?????? Cross that bridge after the joy of tracking too many small-moderate events that offer snow/ice to the forum. A lot to track and maintain an unwavering perspective of what may happen (minimizing big changes to thinking as the models sort it all out). Added the WPC ensemble chance of 3"+ of snow for the 16th. Small chance we'll be #10 ranked Feb snowfall in NYC CP by the end of the 16th. Depends on amounts 11th, 14 leading up the 16th. 547A Tuesday the 9th: Complex and seems to be trending a little warmer so that LI and s of I78 are problematic on much snowfall, with snow/ice mostly nw of I95. Could even have events change briefly to rain over the interior of the subforum. How they evolve...uncertainty. I still think something on Valentines Day and then 1 or two events 16th-18th. Ensembles favor mostly the 16th-18th and give the subforum snowfall especially nw NJ but the trend on amounts is somewhat less. Am cautious since some of the blocking may be relaxing. CFS is comparatively warm and wet and that's bothersome but am unsure how accurate CFS is. For now considering it another member and have to mention this option. All could turn out a little snowier close to NYC but for now, that is not a lock. 815A Monday the 8th: I think we're going to have to see some snow here on Valentines Day I see the warm GFS but for now think its too warm). Amounts uncertain but its pretty clear to me that WAA and short wave coming into the area, then shoots off to the northeast own the 15th, but leaves behind maybe?? the coldest of the season here on Monday morning the 15th. Either wind chill near 15 below I84 corridor or widespread temps down to zero or colder I84 corridor (not that cold urban centers). Tue-Thu 16th-18th: more snow and ice coming I80 region northward. Model uncertainty is large. I'm thinking colder with the precarious balancing of southeastern USA warmth trying to heave northward at times against the generally blocked colder pattern across the northern USA. Rain could be invoked with this. --- Initial post from 2/7 midday. Have included rain in the tags, because we're close to having rain ,at times, within the overall cold enough pattern for snow and Ice, mainly along and northwest of I95. QPF this 5 day period should be in the range of a general 0.5" minimum, to possibly a maximum ~1.5". How much falls as snow, ice, rain is unknown and debatable. Multiple ensembles offer plenty of snow in and to the west and north of our subforum. Favorable blocking for northeast snowfall appears to remain through this period, and well beyond. Am witnessing via modeling and reality, a balancing of the cold core from southwest Canada to the northern Plains and Great Lakes shooting off pieces into the northeast USA, then on into the north Atlantic. These reestablish-reinforce the blocking -NAO from northern Canada to Greenland, and, following each pulse of CAA that moves through our subforum, there is WAA ahead of the next short wave. So far, the cold core has not broken off in total, to change the pattern and so, the snow opportunities continue on and on. February is already off to a special start and we may be heading for a top 10 snowiest February (see attached February Central Park ranking and year). Will narrow the goal posts on these possibilities for this 5 day period as we draw closer. My most confident period of something significant-substantial is the 16th-17th, but I have to consider some of the modeling that likes Valentines Day for an event and also the 16th-17th, delayed a day til the 18th.
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