wdrag

So, let's briefly review 3/20 as the end of snow risk NYC? I don't see anything favorable til 3/27 and even then very-very low chance. Actually looks quite warm to me the last week of March. After that? any sign it can back below normal in early April? Thanks, Walt

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).

Will begin a low confidence thread for 19-early 20 by 630A. Below is my own view (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 00z/15 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.

Good Monday morning everyone. Here's my placeholder for the threads: Less than usual confidence on ice/snow amounts. Tuesday-Noon 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. The snow may never reach Boston? I can see the need for some caution traveling untreated surfaces Tuesday night-early Wednesday. One model: 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. Friday-early Saturday (19-20): Mainly I78-I84 corridors: Rain Thursday should change to a 4-8 hour period of wet snow Friday morning with trace to 2" amounts on untreated surfaces, especially high terrain. There is a small chance that snow continues much longer, into Saturday morning, whereby we'd have a more significant snow accumulation problem, especially PA/NJ. Max gust here in this part of Wantage NJ on Sunday was again 43MPH~6PM.

btw...NAM is starting to join the fray, need the GGEM/RGEM coming up. GFS v15 and 16 now in for NYC-LI potential measurable. I sort of expect the EC to come back tomorrow. What ultimately happens, unclear, but some sort of wintry qpf is coming to a fairly large part of the forum Tuesday and probably again Fri. Late season: tougher accums but this thread continues in the game with a new one probable tomorrow morning if the EC/GFS can keep it lively.

I agree: Will get it done tomorrow morning, once I'm a little more comfortable w it. I think this is fitting the back-back concept in the 16 thread. The modeling has seen many hiccups and so am not convinced of anything yet but can see equal amounts in the forum for both 16-early 17 and 19.

My eye is on it... still too early for me...too much positive tilt. But definitely worthy of further look.

12z ICON? 12z UKMET T-2" nw NJ se NYS-CT. 12z EC? Have no idea what it will say but suspect it will be close to prior 3 cycles.

I am unsure what will happen, but the pattern from then 7th on said, something wintry would occur here. Modeling can't get a consistent grasp. I sometimes wonder about sensitivity to different interactions and that at least in the ensembles and LR ops beyond 5 days, that some sort of dampening needs to be applied to the physics or the chaos is too much. Again, I don't know and this still could be a bust. The uncertainty is the flag not top lock in on anything.

We'll see what future modeling brings, but seems like the heavier trends are coming to the forum via 12z/14 guidance. If the 12z/14 GFSv16 is right, there will be an OBS thread for measurable NYC/LI and up to 5" nw of the city (even the ICON is hitting the Catskills decently).. Modeling for the mid Atlantic on this coming event has been highly variable...disconcerting and so I am unsure of the ultimate solution. Will be interesting to see everything late this afternoon tomorrow as we draw closer.

May be worthy to keep an eye on Friday the 19th. Seems as if n and w suburbs might get some accumulation but model uncertainty (outside the wet 1/2" qpf of both 00z/14 GEFS/EPS) continues.

707A EDT: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.

Just a quick note for the nw-n suburbs (I84 corridor). Relatively small events today, Tuesday-Wednesday morning and around Friday. Spring forward today: wind driven dustings of flurries I84 corridor with maybe a spotty half inch or so? (MA, 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 thread anticipated since trees not leaved. 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. Friday (19): I78-I84 corridors: A decent event of rain and snow. The snow fall is questionable but should be monitored for some possible impact, especially I84 high terrain.

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 associated the cold core aloft sweeping south through New England) seem possible in much of the forum Sunday (14th), with scattered dustings in ne PA, CT, se NYS.

A few reports of max wind gusts 40KT or greater between roughly 2A-450A March 13, 2021 Haven't seen any LSR's yet but am sure there will be a few. My max gust in Wantage NJ was 37 KT (43 MPH). Also appended recent Mesonet graphics from NYS and NJ. KBAF: Westfield, Barnes Municipal Airport, MA, United States [42kt, 22m/s] KBDL: Windsor Locks, Bradley Intl Arpt, CT, United States [41kt, 21m/s] KBED: Bedford, Hanscom Field, MA, United States [42kt, 22m/s] KCEF: Chicopee Falls / Westover AFB, MA, United States [40kt, 21m/s] KEWB: New Bedford, New Bedford Regional Airport, MA, United States [41kt, 21m/s] KEWR: Newark, Newark Intl Arpt, NJ, United States [46kt, 24m/s] KFIT: Fitchburg, Fitchburg Municipal Airport, MA, United States [41kt, 21m/s] KFOK: Westhampton Beach, NY, United States [48kt, 25m/s] KGON: Groton/New London, CT, United States [43kt, 22m/s] KHPN: White Plains, NY, United States [41kt, 21m/s] KHWV: Shirley, Brookhaven Airport, NY, United States [40kt, 21m/s] KJFK: JFK Intl Arpt, NY, United States [47kt, 24m/s] KLGA: New York, La Guardia Airport, NY, United States [47kt, 24m/s] KMPO: Mount Pocono, PA, United States [44kt, 23m/s] KMQE: East Milton, MA, United States [47kt, 24m/s] KORH: Worcester, Worcester Regional Airport, MA, United States [42kt, 22m/s] KPSF: Pittsfield, Pittsfield Municipal Airport, MA, United States [40kt, 21m/s] KPVD: Providence, RI, United States [41kt, 21m/s] KPYM: Plymouth, MA, United States [41kt, 21m/s] KSWF: Newburgh / Stewart, NY, United States [41kt, 21m/s] KTAN: Taunton, Taunton Municipal Airport, MA, United States [40kt, 21m/s]

648A/12: 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.

You may get your wish. No thread (yet) but V16 has a stripe of 3-7" across I84 corridor by 21Z/19 including 2-5" 16th and another batch 18-19. The massive snowstorm on the 12z/11 GFS is probably not likely, but decent wet snow possible, maybe even NYC if we can hold the -NAO long enough. So, back to backs possible I84. 57,59, 67 the past 3 days here at 740'MSL in extreme nw NJ No, a Trace doesn't cover the open to sun ground, but the woods might qualify for a T. Still swaths of 1-2" in the sunny open ground.

I think we need to focus on 3/15-16, more qpf and sooner than some of modeling. GEPS 2m temps at 18z/15 and 16 look quite cold and certainly colder than any previous GEPS modeling. This also fits the colder NAO phase. GEFS has moved confluence north, at least temporarily, so to me, there is no doubt about an event and the focus now is I78 northward, but just how much front end is wintry and how soon it arrives Tuesday are my uncertainties. My last impressions on this til tomorrow morning, at the earliest. Hopefully subsequent modeling comes together = snow/ice to rain for the forum on Tuesday the 16th, ending early 17th.

No plans for 3/18-19 thread (after reviewing ensembles). 12z/11 GFS ops don't have much support from other ensembles and the member that produced the big snowstorm was an outlier (today). I think we need to focus on 3/15-16, more qpf and sooner than some of modeling. GEPS 2m temps at 18z/15 and 16 look quite cold and certainly colder than any previous GEPS modeling. This also fits the colder NAO phase. GEFS has moved confluence north, at least temporarily, so to me, there is no doubt about an event, just how much front end is wintry and how soon it arrives Tuesday. My last impressions on this til tomorrow morning, at the earliest. Hopefully subsequent modeling comes together = snow/ice to rain for the forum on Tuesday the 16th, ending early 17th.

Two things: V16 is not necessarily better than the GFS op. I know it's going to be implemented on the 17th. It is another member. fwiw: modeling... a few times in the past 4 days, has been trying for back-backs snows in the forum (15-16, 18-19). I know a lot of folks are down on 15-16, but just as the 18-19 (not threaded yet), think it good to check ENS and 500MB pattern. -NAO is when best to go for snow here (thats the 16th with a possible last gasp snow the 19th as the NAO starts rising?). So, on 15-16... and a possible future threaded 18-19 (that work will probably preclude being able to follow up very much-except evening), ENS trends are helpful. For the 15-16 event... watch the confluence zone and track of primary vort max. There will be pretty strong 850 inflow ahead of the 500MB vort, and into the confluence zone. That's all I can say right now: I am monitoring confluence zone trends.

fwiw: modeling... a few times in the past 4 days, has been trying for back-backs snows in the forum (15-16, 18-19). I know a lot of folks are down on 15-16, but just as the 18-19 (not threaded yet), think it good to check ENS and 500MB pattern. -NAO is when best to go for snow (thats the 16th with a possible last gasp snow the 19th as the NAO starts rising?). So, on 15-16... and a possible future threaded 18-19 (that work will probably preclude being able to follow up very much-except evening), ENS trends are helpful. For the 15-16 event... watch the confluence zone and track of primary vort max. There will be pretty strong 850 inflow ahead of the 500MB vort, and into the confluence zone. and on 18-19... i think that's purely ensemble suggestive at this point. I think it will deserve a thread either late today or tomorrow, that one also probably a wait and see. Also, I check the CFS every cycle. These events, especially the 19th, were at one time modeled by the CFS

I'm looking at large patch 1-3" snow depth to start at sunrise here in Wantage, other areas fully melted. Still need boots to trod around the yard.

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).

Agreed - ditto here. am at 60.3" (if I measured reasonably accurately). I think you/we get some more 18-19, and then possibly again 22-23. Thereafter, NAEFS suggests warming and struggles for wintry weather returns to our subforum excepting robins (1" max) snow, but i haven't studied LR MJO etc, for which we should informed by others hereon regarding the chances of favorable indices for another surge of winter in early April. Right now, CFS looks pessimistic after the 23rd and not putting much stock in the 00z/06z cycles snow events this far south, after the 23rd. Let's see what we can muster Tuesday.

Good Thursday morning, March 11, Below was my take for a few FB friends along I84 northward. Sunday EDT change and flurries (except small accumulation Adirondacks), then modest wintry episodes next week M (15)-early W (17)and again Th-Fr 18-19. Monday - Wednesday (15-early 17): Snow-ice probably ending as rain for a large chunk of the northeast USA. I84 corridor: 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. 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 anymore). Thursday-Friday (18-19): I80 northward including I84: More hazardous snow accumulation expected but may change to rain. 656A/11 posted 742A/11 Interior NW & NE Burbs 2021 - Page 29 - New York City Metro - American Weather.webloc