wdrag

Thanks. Understand completely. Also nighttime, easier to accrete., Right now, not for tonight, but there is a 50% statistical chance of 1/2 glaze by Tuesday evening near Dover NJ. Snow lovers will be interested if this occurs, especially branches and power. Adding that, to the 16th now.

All: the 18z modeling varies. If the HRRR/GFSV16 works out, all will end the talk of bust for a light event. Both will be better than the 18z NAM/GFS/RGEM. Right now freezing-frozen precip reaching the ground ne PA near Hazleton (elevated) and also near I80 NW NJ (515pm ish). Let's give this a little time before completely throwing in the towel. No matter, it doesn't look like much but enough to be a hazard for the untreated pavement unsuspecting travelers.

5PM check in: Kind of looks like a 12-18 modest ice storm ~0.15-0.40" glaze for the I84 corridor, especially high terrain. Non-freezing rain will probably encroach to near I80 in NJ and southern CT near I95. Here's a graphic from WPC. Probably begins late 15 and ends Tuesday sometime toward midday? At 536PM, added the new 72 hour statistical prob of 1/4" glaze. Pretty high prob down here in NNJ.

Doesn't seem like much, especially nw of NYC tonight in NW NJ, se NYS and northern Ct with anything there, possibly confined to the overnight or early morning hours Sunday. Seems like mostly I78 south across LI. Just have to be safe in this mixed light or very light event. Still almost a 20 degree spread in T/TD up here in Wantage, not boding well for qpf hitting the ground before 11PM up here.

806-810AM 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. One thought: Trof axis so far west Thursday morning that snow can fall in 1000-500 thickness warmer than 540 because of marginal temps- ie the 18th. Eventually as the trough closes in, the WAA overwhelms closer to the surface and further north, with secondary development key to CAD and ice instead of rain.

Good Saturday morning everyone - Feb 13. Lots of wintry elements coming late today-Friday the 19th. Then after Friday the 19th, it warms up a bit as the pattern softens but maybe produces a little more snow for the I84 corridor and Adirondacks the 21st-24th. Any warming and associated non freezing rain this coming week will only soak into the snowpack with little diminishment of what is out there now. Late today - midday Valentines Day: I84 corridor: periods of light showery snow, sleet and maybe even freezing rain across ne PA-nw NJ may not quite make it up to northern CT?-some modeling does it have it there so am uncertain on northern extent. Light amounts. Slippery on untreated surfaces when it occurs. It melts Sunday afternoon. May be Sunday afternoon is a good time to clear off some snow from the gutters SAFELY only! 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 nI84 due to milder temps near freezing but this 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.

se NJ has seen some ice pellets recently per mPing- another handy APP.

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.

Will get obs thread going by 6A... set for starting time around 15z extreme s part of forum and spreads north to 180 in earnest by 21z. It's a mess and will leave types wide open.

Back tomorrow morning but adding one graphic that should alert everyone to potential for some heavy duty removal problems by the 20th. WPC7 day QPF.. most of this should be ice/snow I84 corridor and i doubt any big warmup next Friday. Too difficult to be sure of what will happen but I think I84 has a pretty good chance of 6+ by next Friday- tbd. Modeling continues the heavy snow axis similarly for the past 4+cycles, really back to the 00z/8 cycle. The question on our southern side of the axis, how much of that is erroneously high due to sleet 10 to 1 conversion. Finally: today was beautiful cloudy subfreezing mid 20s day here in nw NJ with deep snowpack. Wednesday the 17th may be the last such beaut before we return to warmer temps starting next weekend (and melting).

yes... I 84 itself looks rather light, the EC seemingly a little better than. Yes, they're in the OBS thread once we get it going.

Will begin the OBS-NOWcast for the 13th-14th advisory event (already a portion of NJ) at about 5A Saturday, gaining a little more confidence on timing the showery mixed precipitation heading our way. Maybe it will be more stratiform? Think it will begin as a bit of snow or sleet at the start NYC midday-afternoon with maybe a few tenths before any change to freezing rain at night, ending sometime Sunday. nw of I95 there's a small chance of an inch or so of snow-sleet, before any ice.

Agreed... and thank you.

72 hour is usually the demarcation for good UA sampling but with such a precarious balance of warm air aloft nearby, we may not know til 24-36 hours in advance. 12z/12 RGEM appears of on its on the 15th with an e lakes low while the V16 i think is correctly colder icy or snowy with a low s of LI. OP GFS in between but for now, I'd continue with a cold scenario with the only problem 875-750MB. Point is... at 72 hours, the models don't appear to have any decent consensus. so for the 18th-19th, ensemble solution is best.

Sorry about the initial attachment posting error.

Fixed the PPT attachment as a pdf and now accessible with hyperlinks making life easier. 1012A/12

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.

Close to final two day CoCoRaHs reports as of 830AM/12.

Have not looked at that very closely. Probably won't. Difficult to beat the models but always look for the edge. Its' trying hard to close off over Texas but then merges with northern stream by the time it gets here.

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.

NO one inch snow probs for our subforum from WPC this morning but it's possible there is a bit of snow accumulation along the I84 corridor spotty 1-2?. Whatever it is, is light and I think only advisory where the eventual ice encroachment. Graphics added from 09z/12 for probs of 0.01 freezing rain. Remarkable I think to see a freezing rain bullseye for LI on Valentines Day. Treated roads would probably be just wet, but untreated surfaces, bridges and overpasses... caution. Probably not enough glaze for power outages unless someone slides into a pole.

Agreed 100% . depends in part on the strength of each WAA pulse and whether we can ever close off something at 850MB s of LI which looks doubtful but I am interested in the eventual progress of these systems. The little ones add up. We'll need to track water equivalent in the remains snowpack on the morning o the 20th.

This thread is basically closed. I took a look at the week in advance post (5th) with the Sunday followup (7th). We got our 1-2" but not 10's; with the heaviest axis SOUTH of our forum instead of northern edge of the forum and while it was foreseen that this could come in pieces, the 12th as named, was wrong. I'm glad we got the 1-2" with 3-6" BWI to s NJ. SOUTH not north of I80.

Not over, til it's over. Today is the 11th, the last event in this coming series is 7-8 days away that may change in its outlook. There could be others the very end of Feb or March. Just in the series, we're living on the edge of decent snow, rather than the heart of there axis.

Issues are discussed with ptype and numerous free links-tools to assist the forecast process without the benefit of NWS data resolution, BUKIT, snow ratios etc This is designed to ball park winter event expectations (lower wish casting) and be prepared well in advance for possible hazardous winter weather. This is only part of the arsenal of internet links that can be of value. NWJO Feb 2021 forum.pdf