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A seemingly - relatively boring advisory light mixed wintry elements event seems to start as snow or sleet near I-195 in central NJ this morning and spreads north to the I78 corridor and LI by mid or late afternoon, eventually changing to a bit of freezing rain tonight. It ends sometime Sunday, probably midday ish. Have ended the topic time as Noon Sunday, since thereafter, temps probably close to or just above freezing with any remaining icing negligible for the remaining daylight hours. The region north of I80 in ne PA/nw NJ/extreme se NYS and s CT should see a period or two of light snow/sleet this evening into Sunday morning but the precip is so light that dry air may evaporate precip with nothing reaching the ground near I-84 in the northern part of our subforum. Uncertainty on precip types and even amounts, but thinking a few tenths of an inch of sleet here and there and certainly slippery at times all untreated surfaces this Saturday evening, Noting any spotty icing near dawn on the 15th as sporadically modeled near NYC is not covered in this thread. Advisories are posted for LI and much of NJ. Please follow NWS advisories and statements on this light prelim event for what appears to be daily bouts of wintry elements in portions of the forum the 15th, 16th, 18th and maybe early 19th. Leaving this last sentence as a place holder for updating the other the other threads by 930AM and deleting at that time once those are updated. Added WPC probabilistic ensemble graphics for today and tomorrow to assist with confidence but are necessarily imperfect due to the proximity of the ocean.

226PM Update: Not changing the thread but if I had to do it over, I might start the snow as early as 930 PM western part and midnight eastern. Also, I'd probably boost the snowfall expectations to widespread 1-3" NJ/PA/LI part of the forum with at least 1 inch NYC, and increase se NYS-CT to trace far north to 1.5inch far south. Minor roughly 6-9 hour snowfall. Should look pretty in the early morning, provided you don't have to drive in it. Not impossible to see a half hour of moderate 1/2SM snow. ---- The first of a series of successive snow-ice events for LI. On-going threads will provide an attempt at future reality detail for each. Modeling has drifted north for the first of 2, or maybe even 3 in our NYC sub forum for the on-going 11-13th thread. Expect 1/2-2" from Scranton PA to NYC-LI southward overnight into Thursday morning with possible spot 3" south of I78. Untreated surfaces will be slippery and it's likely this will have some minor impact on parts of the area Thursday morning commute, a few accidents and delays. Not major but like the Tuesday the 9th occurrence just north and west of NYC, except further south into the heart of the NYC metro area. There is a chance of some 3/4mile light snow with this event as a couple of bands are indicated and snow growth potential is modest but exists. The best axis? Not necessarily southern the edge of the subforum. Maybe we'll know later this Wednesday evening? Amounts in se NYS-CT and northern Sussex County NJ probably a Trace to 1". Less impact there. Snow start time may be 11PM ish for the western parts of the forum but most of the snow should occur in the midnight to 8AM time frame Thursday. -- 749P: Added OKX and PHI snow forecasts to cover the forum and note that advisories are posted for LI/ and much of NJ. Back in the morning.

8AM Thursday the 11th. One event closing out this morning and the the OBS thread will have a CoCoRAHS post around 11A, and a two day summary Saturday at 10AM. Whats coming? I dropped the wind event from the original post on the 5th and also the coldest of the season NYC. Nothing the 12th (my prior concern but unmodeled). 13th.. appears snow or sleet develops late Saturday, probably after dark and ends sometime Valentines Day. Details to be determined. Current modeled warming aloft near 850 MB suggests mostly sleet/freezing rain south of I84 with any snow snow accums in the bulk of the forum under 1" (if anything more than two tenths inch); with 1-4" snow accumulations reserved for the I84 corridor. This is modeled as generally light and appears to be an advisory event due to the probable ice mix southeast of I84. My concern is that modeling of the warming aloft in our subforum I78 northward may be too much, which would allow for a little more snow than now modeled. Jury out. I'm awaiting further model cycles. These impressions include seeing op cycles through 06z/11. -- 235PM Wednesday update (10th): Obs thread updated at 225PM with little change from my 7A Wednesday update; I still think be wary of the dry models for the 12th per the brief potential 6 hr sw 850MB flow WAA pulse (light snow PA/NJ). 13th...seems like steady snow develops for sure late on the 13th in our subforum,. Please see the 14th-18th thread on amounts for the 14th. 7A Wednesday update: The 11th is covered now in the OBS thread. The 12th...be wary of the dry models. Already WAA late 12th in PA. From the initial thread, I left the door open for the 13th. Given the early issuance of the thread on the 5th, I see this as the event occurrence but timing uncertain. Lots going on and timing of late 12-13 unknown, but just a piece of WAA snow. The idea of the coldest of the season NYC probably won't work out for the 13th-14th. Seems like this is mostly snow and won't quote a general amount by the end of the 13th yet. 538A Tuesday the 9th update: Modeling has trended south and remained south, so far, so that our subforum is on the northern fringes of events on the 11th and 12th, and have no idea of the 13th. Modeling is varied but overall depressed. Dropped the 1/2-1" qpf from the title and just riding out. Doesn't seem like much except s of I78 where a few inches of snow may occur, with an inch or so possible the rest of the subforum south of I84. Probably nil far northern CT. Still a delicate balance of short waves moving east-northeast in a fast flow with WAA just to our south. So not giving up completely but the heavier potential from the 00z/6-7 cycles has shifted south. 807A Monday the 8th: Thursday-Friday the 11th-12th: May drop the 13th from this thread tomorrow?? All else is okay, despite some of the more tempered modeling. Too much potential. Need to wait it out another day before any southward adjustments. Periods of snow especially PA/NJ with less certainty northern CT. My initial expectation from Baltimore northward is anywhere from 2-10" total by 11PM the 12th. Best chance of large accumulations I80 southward but who gets what?? Does look like travel problems at times, especially if the first part develops near midnight Thursday morning (or late Wednesday evening the 10th). Snow accums may only be 2" Philly to Baltimore because of freezing rain/sleet? That would place best axis of accumulative snow somewhere down across central NJ in the southern part of our NYC subforum. Lots of uncertainty on details. The 10" may be high but it was initial impression yesterday and I don't drop that unless it's clearly not happening. Ensembles suggest decent snowfall and modeling may yet trend back north? This should bring NYC 1-2" for starters. Think the NAM/RGEM will be helpful on trends. No GFSv16 available (to my knowledge). I do see the 06z EC op is pathetic here in our subforum the 11th. For now, awaiting clarity in modeling. I do like seeing the 06z/8 GEFS qpf and staying further north and snowy on the 11th. Periods of snow especially PA/NJ with less certainty northern CT. My initial expectation from Baltimore northward is anywhere from 2-10" total by 11PM the 12th. Best chance of large accumulations I80 southward but who gets what?? Does look like travel problems at times, especially if the first part develops near midnight Thursday morning (or late Wednesday evening the 10th). Snow accums may only be 2" Philly to Baltimore because of freezing rain/sleet? That would place best axis of accumulative snow somewhere down across central NJ. Lots of uncertainty on details. The 10" may be high but it was initial impression yesterday and I don't drop that unless it's clearly not happening. Ensembles suggest decent snowfall and modeling may yet trend back north? This should bring NYC 1-2" for starters. Think the NAM/RGEM will be helpful on trends. No GFSv16 available (to my knowledge). 730A Sunday: Why stop now... adding NWS ensemble statistical chance of 3" for the 11th-early 12th as more primer for what is coming, (two events or one continuously long 36+hour overrunning? My perspective only is a range of 1-12" for this event with base 1-2" everywhere in our NYC subforum before any change to ice/rain along and s of I80 by the 12th. Best potential for 12" north of I80 (not guaranteeing amounts this high but I think it's good to set a range of possibilities). In other words a decent winter storm is coming but phase changes and amounts of each are in model doubt. I do think ice will eventually occur all the way up to ~I84 with rain on LI and the NJ coast. 743A Saturday 2/6: Added the first graphic from WPC... the rather robust and large coverage Day 7 prob of 3+" of snow-sleet. Uncertainty exists a week in advance on the tracking/merging/intensity of surface lows passing northeastward through the northeast USA late next week. Initial indications are that the event should begin as snow (possibly significant) and may change to ice and rain for a time before ending with a wind driven shot of possibly our coldest air and wind chills by Saturday night the 13th. This event may end up coming in pieces...one on the 11th, with the main event seemingly dominating the 12th. If it is mostly snow, this would increase available potential snowmelt water for the spring.

528A update: OKX snow forecast remains the same this morning. Small chance NYC record 1/2" of snow...southern part of LI should have less snow than than the north. Otherwise forecast looks fairly close from yesterday. Not sure if nw NJ can exceed 3"? I think best chance spotty max 5-6" is I84 or northward, high terrain Catskills to northern CT high terrain. Take whatever we can get. Hope NYC can muster some measurable snow early this morning around sunrise or shortly after. Snow begins 2A-5A west of the Hudson River to the Poconos and Catskills; then thereafter across CT by 730AM. NYC snow at daybreak may accumulate 1/2-1" before quitting and/or changing to rain midday then may end briefly as snow toward sunset. The snow over nw NJ through se NYS and CT may accumulate as much as 6 inches in a few high terrain spots but most of the snow fall should be in the range of 3-5" there. South of I-78 in NJ, to I-I95 a period of snow tomorrow morning may change to freezing rain or rain before tapering off in the afternoon with Trace to 2" accumulations. Untreated roads along and south of I-80 and LI may be briefly slushy in the morning before melting begins. Hilly area untreated secondary roads to the nw to n and ne of NYC will be a bit slippery at times. Snow, especially during the morning commute could result in some accidents and travel delays, especially hill towns. There might be a few school districts in the hilly areas with in-person classes that may close at the last minute, especially se NYS and far nw NJ. Graphics are the OKX snow forecast and the chance of greater than 1" as issued at 330PM.

649A/8. Little change to the thread, except greater emphasis on snow event. Hazardous snowfall of 2-5" for the entire I84 corridor. Mostly the daylight hours but starts ne PA/nw NJ 3A-6A; CT-MA 7A-9A. Will melt on treated roads but caution advised hills and secondarys. Heaviest NORTH of I84, especially northern CT where ~4" common. Expect 1-3" here in northern NJ possibly down to Easton PA as well. Could be a little ice I80 southward too. Plan for possible travel slowdowns. NYC-LI--- looks like snow to start but melts during the late morning afternoon and may change to rain? My take is 1/2" NYC but uncertain. I just worry about melting-like yesterday when probably more fell than the 4.5 recorded but melted-compacted due to urban heat. WPC probs issued early this morning for 1 and 4". Use-rely upon as you prefer. It's going to snow, even NYC but how much NYC-LI and central NJ?? 716A/7 No change to this thread. Think this is reasonable. NYC might get a little wet snow accumulation from this but still on the margins. Will look at this much more closely Monday morning. Overall...a minor event except for where a few vehicles slide off the road along the I84 corridor or folks slip and fall stepping outside in that area, even down into the suburbs immediately west and north of NYC. Sometimes most of the accidents are in these small events. Therefore, even though a minor climo event for the wintry weather elements, it's still significant for those who are directly impacted. It appears LI (NYC) and the region along and s of I78 will be too warm for any accumulative snow, but it is not impossible to see several hours of wet snow there as well with something minor, especially if it arrives prior to 9AM. This primarily looks to be ne PA/nw NJ potentially hazardous snow event across to CT/MA. Amounts east of the CT River may end up closer to the 5" of the expected 1-5" range. This is a WAA pattern behind the departing Super Bowl Sunday event. Tentatively expect all treated valley and coastal roads will be mostly wet but could be slippery at times? Hilly terrain should be slippery at times, despite treatment. This water content, while minor, adds to the accumulations already on the ground and well insulated or unheated roofs PA/NJ/NYS/CT. Will add more graphics tomorrow, once we get past Super Sunday. The initial graphic is the low chance of 3"+ of snow per the WPC ensembles.

Models showed this possibility earlier, took it away, and now seem to be bringing it back for some of us. Doesn't really matter, John's making his annual trek to Nooga to watch the game and that means there's a 70% chance of snow along and north of I-40 at least! Good luck to everyone!

Snow should begin near I-195 in central NJ between 4A-6A and spread rapidly northeast, with the heaviest bands of snow occurring between 10AM and 3PM in the forum. There should be some arced banding along I95 into LI and snow ratios may end up higher than 10 to 1. A short duration and according to the experimental Winter Storm Severity Index (WSSI), be a moderate impact storm along the I95 corridor eastward across LI with minor impact nw NJ and ne PA.

While all model snowfall output has to be taken with a grain of salt, which platform do you all think uses the Kuchera snowfall method most properly? It seems WeatherBell is always cranking out higher totals than Pivotal - despite using the "same" method (Kuchera). Thanks!

A challenging period of travel is possible Friday morning across northwest NJ, northeast PA and se NYS; possibly into the CT portion of our forum as multiple bands of precip sweep eastward across the region. Amounts will be light but where possibly freezing rain or sleet, untreated surfaces could be quite slippery. Additionally there will be a tendency for any rain/freezing rain to briefly change to steady snow even to just west and north of NYC with little or no accumulation there, while high terrain in nw NJ/ne PA/se NYS and w CT are modeled to pick up 1/2-2" before melting begins ~ 11 AM or Noon. mPing. This thread will help concentrate interest Friday mornings system while the other threads occupy the Sunday event and beyond.

Less than a week out and all indicies show both Carolinas getting something... So let's bring this one all the way home

January Discussion thread, figured it was time to start one given how close we are to the new year.

mPing should be interesting. The advisory for a mix of wintry elements will probably start with a burst of decent snowfall rates between sunrise and 2PM before a probable change to rain, freezing rain or sleet on LI and I80 southward during the afternoon and possibly back to ice or snow early Wednesday. The i84 corridor should be mostly snow, if not all snow. The region southeast of I95 in NJ after starting as snow or sleet should transition to plain rain by Tuesday night but it might be marginal for icing in Monmouth-Middlesex counties near the colder air sitting astride I80-LI. This I believe is the first expected widespread winter weather advisory event dating back to at least January 3. There's a small chance for a period of flurries along I195 to maybe near I78 in NJ between midnight and 4am but the main event in the NYC forum begins during the daylight hours Tuesday.

Models are on the uptick state wide with the GFS being downright aggressive. So if figured we may as well have a last minute forecast and Obs thread for it.

Fifth topic edit Monday 635AM Jan 25, since the topic started Tuesday Jan 19: 35 AM Monday Jan 25: Added two graphics for the coming extensive minor snow-ice-snow event with main impacts LI-NYC-I95 corridor northwestward to the Adirondacks and New England Could be sneaky icy along the coast. mPING will be helpful. NWS snowfall forecast map added from 5AM this morning (NYC-LI generally less than 1") and also the probabilistic chance of .01 freezing rain. Mostly a Tuesday-Tuesday night snow-sleet event changing to freezing/rain-rain during the afternoon I80 southward possibly going back to snow or flurries Tuesday night or Wednesday morning. Advisories already out near DC. Expect it will be briefly slippery everywhere in our forum for a time Tuesday, and probably Tuesday night-Wednesday morning LI-NYC-I80 northward, especially interior. Expect plowing small amount amounts of snow entire I84 corridor with road treatments necessary most of the remaining portion of our forum except possibly just southeast of the I95 corridor. Weak boundary layer winds with a north-northeast drift will probably assist on keeping temps on the colder side of the available guidance. Storm impact of all snow will be larger I84 northward and inclusive of I90 to Boston with decent amounts. This keeps this brief and we'll all be monitoring the models. Hopefully there are no slips/falls/accidents Tuesday-Tuesday night on all untreated surfaces. Fourth topic edit Sunday morning 550AM: This is mostly a Tuesday-Tuesday night event. Periods of mostly light snow, at times changing to sleet, freezing rain (rain where above 32F along the coasts) or freezing drizzle up to I80, NYC, LI. Snow amounts trimmed a bit and I sure hope NYC can muster 1/2-3" depending on precip type and intensity for this event. I pushed the start time back to 7P Monday but it could be delayed NYC-LI-CT til as late as 9AM Tuesday. Also took MODERATE event out of the headline. Banding signature suggests snow should break out across PA/NJ between 7P and midnight Monday. The primary event is the 26th, ending sometime Wednesday morning. While amounts are light, suspect there will could be a period or two of 3/4mi light snow - bordering 1/2S for an hour or two, from northern NJ into ne PA/se NYS and western CT. 06z/24 NAM banding signature and also seen in the 06z/24 GFSv16 qpf, that the heaviest snow may occur early Wednesday near NYC. This may be associated with a trowel/inverted trough departing shortwave and weak seaward moving low pressure. Something to monitor but not get hopes overly high. So, manageable delays sometime during this event due to plowable snow northwest of I95, except snow-ice I80 southward in NJ to Baltimore and snow/ice/rain NYC-LI southward along the NJ coast southeast of I95. Amount expectations lowered to range from an uncertain 1-4" CT with the least in eastern Connecticut and a less than certain forecast there, to between 3-5" se NYS, ne PA and 2-4" nw NJ north of I80. Temps will generally be subfreezing throughout the event except NYC/LI/NJ coast which are in the margins of ice-snow at the start, changing to periods of rain then ending as snow, so amounts of each element will depend on duration but it will probable get slippery there on untreated surfaces for a time as well-especially if and when precipitation occurs during the nighttime hours. Check others herein and other resources for other opinions. --- Third topic edits 626A/23: Delayed the start in the forum 3 more hours and that may not be enough due to the dry air in place, but sometimes the snow-sleet breaks out faster than modeled. I've had to admit a slower departure, especially because of the GFSv16 and EC. The following may be too high on amounts but it's just my opinion of the boiled down (in my mind) consensus of the 00z-06z/23 model suite. A colder week is now here with hazardous winter weather potential late Monday-late Thursday Late Monday the 25th-early Wed the 27th: Manageable. Still uncertainty on evolution. There is general model consenses for slower arrival and later departure, and less precip amounts. I am guarded about decreasing the wintry element amounts (low level pressure pattern, 500MB vort max track, GFSv16) but this update below may be an inch or 2 on the high side? Manageable delays sometime in this event due to plowable snow northwest of I95, except snow-ice I78 southward in NJ to Baltimore and snow/ice/rain NYC-LI southward along the NJ coast southeast of I95). The main event for I84 should Tuesday-Tuesday night. Expecting amounts to range from an uncertain 1-5" CT with the least in eastern Connecticut and a less than certain forecast there, to between 4- isolated 7" se NYS, ne PA and nw NJ. LI/NYC/NJ coast 1" to possibly as much as 4" by the time all is said and done with the best chance for a POSSIBLE 4" NYC (possible, not probable). I expect plowing will be needed sometime for most of our area northwest of I95, except maybe east of the CT River. Temps will generally be subfreezing throughout the event except NYC/LI/NJ coast which are in the margins of ice-snow at the start, changing to periods of rain then ending as snow, so amounts of each element will depend on duration but it will probable get slippery there on untreated surfaces for a time as well-especially if and when precipitation occurs during the nighttime hours. Check others herein and other resources for other opinions. Second topic edits 645A/22: Made it definite put in a time structure of Noon Mon-6P Tuesday and withdrew possibly from the description. Good morning this Friday Jan 22: Think consensus is developing that most here will enjoy a significant plowable snow event late Monday-Tuesday. My take below based on 00z/22 ops and EPS/GEFS/NAEFS, and 06z GFS op. Good Friday morning everyone, Jan 21. Focus shifts from the Adirondacks today to the region from I84 to NC next week, then back north to the I84 corridor northward the first week of February. This may be as good as it gets for our membership this winter who like snow. One event at a time follows. Travelers into the northeast USA Noon Monday- 6PM Tuesday the 25th-26th: While still some uncertainty, if you have travel plans into the I84-I80 corridors or I95 Baltimore to NYC-New Haven Monday Night-Tuesday morning, prepare for delays due to snow, except snow-ice I78 southward in NJ to Baltimore. Expecting amounts to range from ~1" or less I90 in Mass (could be zero if the storm stays south), to an uncertain 1-5" CT with the least in northeast Connecticut (Ashford) and a less than certain forecast there, to between 4-7" se NYS, and 5-9" ne PA, nw NJ. The high side 9" amount is no guarantee but it's in some of the modeling. Best chance of 9" in ne PA is along I80. LI/NYC my expectation this early is 1 to maybe as much as 6"??? with the best chance of 3"+ western LI/NYC. I expect plowing will be needed most of our area except maybe n CT/MA/and the region along or just southeast of I95 BWI-NYC. Temps will be subfreezing throughout the event except if it starts Monday afternoon when it will take an hour or two to drop below freezing. Baltimore-Philly is in the ice-snow zone so amounts of each element will depend on duration but it will get slippery there for a time, possibly as early as Noon Monday. Finally: the end of this event should be Tuesday afternoon, but it's possible that it could linger into the wee predawn hours of Wednesday? Attached a NWS graphic ensemble 30+% chance of 3+" of snow Monday into early Tuesday. Blue is 50+%. This gives an idea of the focus only through 7AM Tuesday and it will snow beyond 7AM Tuesday- so this is conservative. Also the NAEFS qpf for the 24 hr period ending 00z/27 with .4" = to the 10MM line, and also the sfc temp for near 00z./27 which shows 0C along I95. -- First Topic edits 630A/21: Added widespread to the topic title. Uncertainty continues, especially northern extent of 2+" with I84 somewhat in doubt because of the last 24 hours of GFS depressed cycles. However, the GGEM/GEPS, and especially the EC/EPS have come back north since the 00z/20 cycles. NAEFS is still south, and one can debate if the event lasts into Tuesday night but overall, the topic stands with considerable debate on what happens. I've added the latest WPC probability of 1/4" melted w.e. frozen which you can see has trended higher and more expansive and i think that is correct. It does not match some of the WPC prior to 08z/21 qpf which looks slightly lighter but going with the WPC prob, be cause of the GEPS and EPS. My take at 6A/21 Travelers into the northeast USA Monday-Tuesday the 25th-26th: Still considerable uncertainty on how this all transpires but we should be aware that an extensive hazardous wintry episode is expected for all untreated surfaces, especially the I84-I80-I95 corridors from Baltimore to I80, with less certainty I84. The front end Monday start time is uncertain. It could start for a couple of hours Monday morning then stop for 12 hours. The bulk of this event probably occurs Monday night into Tuesday the 26th. Odds favor a change to rain or ice along the I95 corridor Tuesday morning the 26th, but mostly snow northwest of I95, especially the I80 corridor northward. There is considerable uncertainty on where the primary snow or ice event will occur in the northeast so its good to be aware of the possibilities but no action recommended yet, unless you're headed to Baltimore-Philly where messy slippery wintry elements develop by Noon Monday. Below is the initial topic start from 940A/19. Since there has been a lot of 25th-26th discussion prior to this topic start, let's continue it here. Potential exists for an advisory event in the NYC forum, but with uncertainty on how much coverage and where. -NAO blocking and the strength track of the short wave breaking through the Appalachian ridge will ultimately determine the northern extent of wintry qpf, and amounts. Solutions vary greatly but 00z-06z/19 ensemble consensus permits on the order of 0.1 to 0.5" qpf in the forum. 00z/19 NAEFS thicknesses and sfc-bl temps suggest snow or ice probable for at least a portion of this event with the eventual change to sleet or rain probably LI westward to just s of I80. Timing: Appears the first wintry elements should begin the 25th (possibly as early as 10AM) and should pretty much end by 3PM Tuesday the 26th. Outliers: Have not placed much confidence on one or two operational warning event qpf's through the 06z/19 cycle, since ensembles appear to be predominantly less than warning. Maybe that will change but it's what I think is realistic at this point. This topic will be amended as we draw closer to the 25th with more consensus. A following short wave late 27th-28th appears to be steered south of the forum by the shortwave of the 26th redeveloping blocking northwest flow aloft over our NYC forum by the 27th. The attached graphics are from WPC derived prior to the arrival of the 00z/19 cycle ensembles, but an idea of their upcoming ensemble solutions. Darker green shows their 30+% chance of more 1/4" melted water equivalent (w.e) snow-sleet. As you can see, it's inland-higher terrain favored but that doesn't rule out a widespread 2+" snowfall elsewhere. This is a D7 forecast. There will be changes as the models change.

Low pressure in the Virginia's late Wednesday will get picked up by an intensifying short wave moving east across the Mid Atlantic states Thursday and become a pretty good sized nor'easter as it departs the mid Atlantic coast Thursday afternoon. Does development occur fast enough to bring significant wind driven snow to a part of the NYC forum (rain or snow LI/NJ coast?)? 12z/23 GEFS is fairly robust on qpf, but further south than it's 00z/23 version, while 12z/23 EPS and GEPS are indicating too little too late. One small caveat: the low levels should remain fairly moist after the Tuesday - Tuesday night ( 26th) event (whatever it is) and there may be some advance snow or snow grains/freezing drizzle/drizzle late Wednesday or Wednesday night, in part related to leftover moisture and some sfc convergence. That too is an unknown. Added the WPC day shift forecast qpf and chance of 3+" of snow (darker green). Will update Monday the 25th, when some of the nor'easter threat to our area has resolved itself. Also added the NAEFS qpf... seems a little high near and north of I80 but it could happen. Also added the 12z/23 GEFS 500MB spaghetti for 12z/Thursday.

Figured with this within 72 hours of laying down some Mississippi snow love we may as well have a separate thread for it. Virtually all modeling is now hitting parts of Mississippi with a good bit of snow that washes out as it heads NE into Alabama and Tennessee. Several models who are performing well this winter have some N Miss and West Tennessee love to share. The latest RGEM was very bullish with the entire western half of the state seeing snow at 84 with a good bit down in N Miss and West Tennessee. GFS is so progressive this year it can't be relied upon in the d2-7ish range. Ironically it actually nailed the Christmas event at D9/10 then lost it to the East until the last minute. So ride a Canadian/Euro blend and hope for victory! Good luck to the western valley with this one!

Good Wednesday morning all, Jan 6. Unless something highly unusual occurs, I've made my last update for this topic. This was a busted January 2 outlook that faded with model cycles only 24 hours after issuance, beginning around the 00z/3 cycle., blocked to our south and southeast. Good Tuesday morning Jan 5: Update dropped the 8th from the topic, and dropped the tag of ice. The preponderance of 00z/06z January 5 2021 guidance favors a miss for this developing mid Atlantic coast nor'easter and so my Jan 2 confidence is probably wrongly over confident for an 7-8 day outlook. However, we're still at 96 hours (4 days) with somewhat delicate northern-southern stream trough interactions in the northeast USA Friday and Saturday. Some of the guidance has minor amounts of precipitation skimming the NJ coast/e LI with ensembles interestingly showing a little more extensive minor qpf coverage for southern New England. That New England coverage may be due to the eventual development of an upper level low over central or southern New England on Saturday (light wind), and a possibility for a period of easterly flow aloft , caused by the flow interactions of the modeled offshore storm and the northern stream short wave in New England. So it would not surprise to see some light or very light snow on the coasts into CT/MA but for now--- please go with your take on the event. I can't push this occurrence in the face of all the recent 3 days of modeling. We're still 96 hours in advance of the storms passage and once in a while models make significant adjustments in somewhat uncertain northern -southern stream interactions. -- Happy New Year and welcome to what will probably be the 3rd wintry event of January 2021! Just too early to detail but ensembles have something. The current Aleutians east central PAC short wave is modeled to dive southeastward into the nations mid section and by Next Friday the 8th turn northeastward into the northeast USA. This could be snow to ice to rain, but something wintry is coming (my guestimate is a 70 to 80% likelihood). Is there enough cold air and confluence in the right area of northern New England to allow-keep it wintry? -NAO Block impact? Will update these tags and potential impacts when confidence increases. Just wanted to get this thread started for any comments/model considerations etc as we move forward.

January 2, 2021 605AM Update: Am probably not commenting for our NYC forum on anything beyond 9AM January 4, which is about the still possible extension for eastern New England. That part of our oncoming light to moderate Nor'Easter snow event for the entire I84 corridor, will not happen for us. The remainder of the NY Day comments below seem reasonable. My anticipation is a widespread plowable 2-6" elevation dependent snow event from I95 northward through the I84 corridor and probably I90 eastern NYS and northern NJ/ne PA eastward through southern New England. I-84 valleys will manage this better because of marginal melting temps (32-34F) and the southeast edge near I95 will also be manageable, in part because a little rain/freezing rain/sleet is possible there. as well as the daytime temps near 33F. So, it's a mixed bag but the I84 corridor should enjoy this, with the primary event mainly Noon Sunday-6AM Monday. This storm will probably affect some of the return home holiday travel and also may force some Monday morning 2 hr cleanup delays, especially CT-MA portion where it still may be snowing a bit. NYC-LI should see a touch of snow/sleet but whether it measures or not and where, i don't know. My guess is eastern LI may do a little better and thats where there will probably be some wind gusts to 35 MPH but NYC might also see less than an inch?? There will be 1 or 2 brief periods of moderate snow with this event, but I'm not thinking of more than 10 to 1 snow ratios, possibly only 7 or 8 to 1 near I95. Will begin the OBS/NOWcast thread later tonight. Earliest part of snow/sleet/very brief ice arrival is around 8A-10AM Sunday for our NJ eastern PA membership. I don't anticipate adding any further potentially helpful information until maybe this evening. Noting the WPC ensembles for more than 2" are not very enthusiastic for this event, so we need to keep in mind failure. They also weren't as enthusiastic as they should have been for glaze this past night and the SPc SREF did much better. It already has 2-4" in ne PA by 7PM tomorrow night. Keep an eye on the SPC HREF MEAN snowfall after the 12z/2 cycle completes around 1030AM. The HRRRX was all over the place for this freezing rain/sleet/snow event that is wrapping up now and am not referencing it today. I as others here , like consistency in the modeling. One event at a time. NY Day 2021 558AM quick update: Extended the date to Jan 4. Ensembles suggesting a pretty good chance of 3+ inches for some the I84 corridor high terrain in possibly two long duration episodes. A short wave diving into the back side of the initial short wave trough may prolong the event considerably for the New England portion of the forum by forming a a very slow moving upper low along the New England coast. So it's complex but potent, especially if the 850-500 MB lows form in a favorable position for banding on the northwest side of this storm near I84. Just too early to overcommit but this could be a nice snow event for the I84 corridor and as previously proposed (modeled), can't rule out a touch of wet snow on the back side for NYC and especially eastern LI on the 4th. Just too early, especially with marginal thermal profiles and absolutely do not want to buy into any 8" amounts seen on some of the single member operational models for New England, at least not this early with so many differing solutions. If it's progressive and mainly afternoon of the 3rd into early 4th, then the 8" amounts won't happen and this would be an interior I84 standard climo modest event. Graphics is the 00z/1 GEFS prob of 2+ inches for this coming storm-- 10 to 1 ratio. Just an idea of primary risk area. --- Uncertainties exist including how much deepening and track for NYC subforum qpf, timing thermal profiles for phase change to wet snow. Looks like it will happen despite GFSV16 dropping it in recent cycles. EC has been on it for 3 successive cycles (prior to the 00z/30 cycle) and EPS now throwing out decent qpf (still does with the 00z/30 cycle) and a bit of snowfall all the way down to LI (questionable but could occur late in the storm and not be much...but??). 12z/29 NAEFS has it a little and the fact that the 12z/29 GGEM lit into it, also the 12z/29 UK, should be enough for us to give it a good chance to produce snow down to at least the I84 corridor. Others have been wanting a topic to track the models etc for this increasingly likely Sunday January 3 potential nor'easter. The initial precipitation (rain) from this initially weak Virginias low pressure system could begin after sundown Saturday Jan 2, as rain. As it intensifies and 500 MB heights lower, the combined lift, cooling thicknesses plus north-northeast wind advection of somewhat colder boundary layer temps southward, should change precipitation to snow along the I84 corridor by early Sunday, and possibly down to I95 west and north of NYC by nightfall Sunday? Rain over NYC and LI possibly ends as a bit of snow later Sunday or Monday morning? Probably too early for all this scenario detail but it's based on the 12z/29 NAEFS, EPS, GGEM, UKMET. No snow amount forecast though it appears that elevations should have highest accumulations, presuming it does snow. Snow looks to be slushy during the daytime and generally controllable for road crews, especially valleys, since daytime melting of any snowfall would occur during periods of lighter precipitation rates with marginal temps of 31-34F. LOW chance paragraph but reserve the option to increase IMPACTs of wet snow, add a small chance of gust 50MPH LI and minor flooding for a couple of NJ/PA rivers based upon the already anomalously wet December, plus future unknown qpf's from Jan 1 and 3...IF qpf up to I84 increases to 3/4" and mostly snow along I84? This is unlikely for now, but could happen, especially in the deformation zone if a closed low to 700MB develops near LI in this positive tilt trough. After review of the 00z/30 and 00z/31 cycle-no changes. Best to keep options open and look to the I84 corridor as most likely area to see some snow. Marginal thermal profiles the continuing concern. 00z/31 ensembles are growing qpf... but surface and upper lows may be too close to LI/se MA for much snow in the NYC subforum. This looks to me to be mainly an elevation I84 corridor wet snow concern. Definitely cannot commit any further details - just too uncertain and that uncertainty may continue another day or 2. Far from an ideal snow event, but also the typical winter uncertainties for our area.

Mostly all rain should be confined to the region s of I-78, LI-NYC. Sleet or snow begins near I78 ~9 or 10A and spreads northeast, possibly possibly drying out to flurries reaching CT/se NYS midday. Thereafter the bigger part of this event occurs 2PM-2AM as mostly wet snow just nw of I95. Heaviest snowfall seems slated for the elevations including the Poconos-Catskills with 3-5", 2 to possibly 5" rest of se NYS, nw NJ along and north of I80 to the Merritt Parkway-in other words west of the CT River, but possibly a dryer zone of under 2" to at most 4" ne CT-central MA. These amounts are uncertain-based on guidance through the 06z/3 cycle. There will be melting on pavement today below 700 feet elevation during the day but a plowable snow seems certain for the hilly areas, especially w of the CT River with accumulation on all untreated surfaces after sundown. The precipitation driver will probably at least in part be an inverted trough developing northwest from a rapidly deepening low pressure system heading east northeast of the mid Atlantic coast. The inverted portion of the trough should be back to the Poconos and that I think is why the heavier qpf tends to be modeled there.

A routine wintry ice event, that will create some travel problems in high terrain above 1000 feet late today and early tonight, primarily along the I84 corridor.

We are hitting well into the window for December discussion. My best event of winter was on December 12th last year and I believe in 2019 it was a December event for the far Eastern areas. That was as the pattern of a very cold November bled into December. To get there this year we are going to have to count on the pattern to switch in December itself. Hints that it may, at least for a short time, as we head into the last few days of November and first week of December.

Topic Edit 508AM: Added HIGH IMPACT and the time back in to the topic and extended 4 hours. Strongest winds in NJ/ne PA/se NYS roughly 10PM-4A, NYC/se NYS 1A-6A, LI/CT 2A-to possibly as late as 9A/25 e tip of LI. Minimum wind gust on LI 55 MPH with max 75MPH, NYC-se NYS minimum wind 50 MPH isolated max 70 MPH. Please follow NWS on all warnings/statements. I'll leave it yourselves to add graphics etc as need be. I'll begin an OBS-NOWCAST thread by 6A. Have not looked at soundings but everything else discussed in yesterdays 518AM topic edit below including HSLC SVR's continues. We may reach within 2F of the record 66F-2015 max temp for Christmas Day at CP. Flooding of some of the larger rivers, if it is to occur, may be delayed 24 hours or more after after the rain quits Christmas morning, Max rainfall axis in our forum looks to me to be CT, isolated 4", not including snowmelt runoff. If anything is missed, please let me know. Thank you. Topic Edit 518AM Wednesday 12/23: No significant changes. The prime threat period might by 2 hours too fast but not enough evidence to change the primary initialization period of weather related issues. My assessment tells me to prepare, without science, for many many thousands without power starting 9PM to midnight Christmas Eve evening, and then across se NYS, LI, CT, MA beginning midnight to 6AM Christmas morning. Gusts NYC airports should be 45-55kt, with potential for isolated 65KT LI/CT/MA. I expect SVR's for the HSLC lines of heavy showers to help focus the primary short-fuse threats. Lower chance of any damage northeast PA but ridges there will be most vulnerable there to ~ 55 MPH gusts. There is limited science on power outage wind damage with leaved trees, without, softer unfrozen ground versus frozen but I don't have this information nor any private services predictive algorithms. I still think that wind damage will prevail as the most important aspect of this storm, but please follow NWS flood watches, warnings as issued, due to the combined snowmelt and new widespread NYC subforum rainfall of 1-2", with isolated 4" potential inland-most of this in a 9 hour period during Thursday night, Any snow on the backside is exceedingly minor on the I84 high terrain. There actually might be a little better chance for a slight coating of snow Christmas night with the weakening trough aloft passage. --- Topic edit at 526AM Tuesday the 22nd: Changed the title to WILL be accompanied by damaging wind LI, and restricted the period of accumulative snow to the interior. I think the wind damage potential is the largest threat from this rapidly deepening 980s surface low moving northward up the front into NYS predawn Christmas. SVR's possible (in my mind likely, even if no lightning) for High Shear Low Cape (HSLC) heavy showers.The Richardson (R)#/wind profile combo on the NAM and even GFS tells me 45kt+ gusts all the major airports in NYC sometime between 10P/24 and 5A/25 . This is further supported by multiple models 80KT+ 850MB winds over LI, in some cases around 90-95kt. From my looking at R# and wind grab, this has the most favorable potential in my past 3 months of examining to realize downward transfer 50-65KT from the lowest 25 to 50 MB of the boundary layer. Whether an isothermal sounding in the lowest part of the boundary layer, or even a slightly inverted sounding can diminish-mute the potential, I don't know. What I do think, is that a lot of folks could wake up with lights out Christmas morning across LI, and possibly NJ/CT. Flooding potential to me looks the same as it did yesterday-previous days, all a matter of qpf, snowmelt combo to prompt a few rivers into minor or eventually moderate flood stage, even as temps plummet from 60ish near midnight Christmas morning, to near freezing by ~ Noon Friday. Please follow NWS closely on flood potential-they have more tools than I. Snowfall, accumulation less than 1 inch probably restricted in our forum counties only I84 high terrain northwestward. I'll copy this to the last page of this topic and add a couple of wind profiles there. The future posts will look at FOUS BL winds, which I think will exceed 34kt at LGA and BOS around 06z and 12z/25 respectively. IF not, then I'm a little too severe on my wind expectations. Also, I'll be adding shorter term wind gust potential graphics, especially Wednesday onward. (corrected many typos 826A) --- Below from the origination date of Friday evening the 18th. This topic is started primarily because of the recent operational model cycles at one time or another offering a more than ordinary 12-18 hour period of weather here near Christmas, on top of melting snow. Always uncertainty. Uncertainties abound, including how far inland can a couple of hours of 60 degree temperatures penetrate to melt the snowpack, and will there be any hazardous snow accumulation closer than the hilly western and northern suburbs? Add to that, is there an inversion thats prevent excessive low level winds from reaching the ground.? Snowpack will be melting a bit the next few days,, til a sudden brief surge of 60 degree warmth Thursday evening or very early Friday morning, associated with a strong cold front. That front is embedded within a high amplitude trough. It's slowed by a strong 1030-35MB high anchored near the Maritimes, and there is potential for northward moving low pressure along the front, as it traverses across the NYC forum. Max rainfall should be concentrated just inland (se or sse surface wind) and combined with remaining snow, may? be enough to promote some small stream flooding? Flooding will be dependent on how much snow melts on the 24th/early 25th combining with around 1" to possibly 2" of rain, prior to the sharp cool down to near freezing by midday the 25th. Current 12/18 river response models to multiple ensembles are not alarmed at this point so I don't want to make this look worse than it will be. Of greater concern is the ECMWF cyclic offering of 60+ MPH gusts to LI (50 inland) which may cause some damage. Recent experience with the storm of the 16th-17th suggests to me, that we will need at least 60 MPH gusts to see significant damage along the coasts and ridges. It's possible - IF the 850MB southerly jet can exceed 75 knots, preferably 85 knots. The 18z/18 GFS has 80 knots for e LI and the 12z/18 EC has near 100 knots for all of LI. IF the ECMWF were to verify, it would be lights out for many and not a pleasant Christmas morning. Timing of the event probably sometime at night (6P/24-6A/25 EST) Snow: Backside snow doesn't often accumulate significantly with temperatures falling rapidly from the 60s to near freezing. Thinking best chance I84 corridor high terrain sometime Friday morning the 25th. Graphics: 1) 12z/18 EC 850 wind. EC surface gusts, GEFS chance of 60 MPH wind gusts early Christmas and finally, the WPC qpf forecast from ~18z/18. 608P/18

Figured we’d go ahead and start a thread for this possible storm so we could have a separate thread to look back on it In the future. Middle and East Tennessee look to have the best chances with this system, (hope west Tn can creep into this scenario as well). Either way it’s nice to have something to track around Christmas time as this doesn’t happen very often. Fingers crossed we all can have a white Christmas! Let the speculation begin.

Periods of light snow or flurries today in the I84 corridor will possibly maximize their accumulations near Interstate 95 between 10AM and 3PM with a narrow stripe of 1," possibly just sw through north of NYC and a chance of measurable in the city. Not all models agree but the NAM, RGEM, HRRR from 06z/20 are on board. Doubt if it will much impact on well traveled pavements, especially treated, but side streets etc may become slush covered with this pleasant refreshing of the snowpack, wherever more than 1/4" occurs. Central and eastern LI may not see snow or if any, it would be too warm for accumulation. Checking the 3K NAM profile, there is a small chance visibility will lower to 3/4 mi in S- for an hour or so during midday. For the I84 corridor, maximum snowfall appears destined for CT and occurring there mostly this afternoon. One experimental snow accumulation graphic is added from 06z/20 (HRRRX) Not for this thread, but a heads that increasingly unstable moist lapse rates may bring a surprise 1" to parts of our NYC suborum between 10PM Monday and 10 AM Tuesday with the passage of a fairly strong cold trough aloft. A separate thread will be started for that on Monday, if that speculation still looks reliable. 536A/20 Edited 105PM: Looks like nw 1/4 NJ and a part of interior se NYS, and most of ne PA will have missed this minor short duration negligible impact event except to brighten the spirits of the snow enjoying families/shoppers. I thought we'd at least get flurries up here but NOT so far. Not complaining. Just an observation. Nice day up here, despite no snow. No change on thinking for early Tue. 103PM.

This may be the first of 3 storms this week (14-19) with northeast wind in the NYC forum and a strongly -NAO with blocking in progress, that could dump up to a foot of snow, (in total) on parts of the forum by midnight Saturday. Uncertainty exists, especially intensity of the storm and associated upper air pattern, as well as it's track. This one so far with uncertainty on the r/s line and qpf amounts but potential exists for several inches of wet snow on the northern fringe of this late developing but weak nor'easter as it passes to our south. It may finally bring NYC it's first minor measurable amount of wet snow (twas a close call on Dec 5th at CP). Tides are astronomically high so that there is a small chance of minor flooding in a few spots at the time of high tide both Monday and Tuesday morning's. Since most of the snowfall (or of any snowfall) should be during the daylight hours Monday in our area, pavements will tend to be wet where it snows except the hilly areas west through northeast of NYC, if it occurs there and comes downs hard enough. This is probably a day, to get snow stakes into the as yet unfrozen ground, and prep your snow blower-thrower for possible use Wednesday. By the time Monday afternoon rolls around we should pretty much know whether this will be a week of substantial snowfall for parts of the NYC forum.