wdrag

610A updated thread....my last topic update and all my other posts will be in the observed below. Adding several graphics from the 4AM NWS forecast process inclusive of the ICE STORM WARNING coverage area (purple), the HPC HREF ensemble 1/2" of glaze expectation by 7A Tuesday (blue), WPC ensemble probs of .10 glaze (orange) by 7A Tuesday and the much lower prob of 1/2" glaze. I would expect power outages in the NWS warning area and SPC HREF Blue coverage area. IF these amounts work out- I think it will be big. Modeling doesn't necessarily guarantee freezing longer than 4AM Tuesday, so if it's not, then the rain is non freezing its heaviest 3 hour period. Still the ground is cold so I'd plan on a bad night, and in fact a bad day today in the I84 corridor on all untreated surfaces. Regarding info near NYC... just be careful. Untreated's slippery near NYC-LI today-this evening, should ease sometime tonight. Looking at 06z/15 NAM FOUS...if that surface wind stays ne in NYC through tonight as the sfc low transits coastal NJ, the guidance will be too warm at the surface. This needs careful monitoring. My guess, via the 06z/15 guidance, there may be an underplaying of extensive ice damage, especially just west of the 4AM warning. Just a degree or two makes a huge difference. I'm not expert enough to know for sure. So for me here in Wantage NJ, if its still 31-32F at 4A Tuesday, we've got pretty big problems in far nw NJ/se NYS/nePA. We will see how the probs work. Prep worst and hope for the best. While a bit of snow is possible Monday along the northern edge of the subforum, most of this event should be freezing rain or rain with heaviest amounts Monday night. Sleet may occur as well for a time Monday. If freezing rain lasts long enough in the warning area of the forum, and accretes thick enough, tree damage and power outages would occur. Spotty poor drainage street flooding is possible in NJ, LI. 21z/14 NWS ensemble high probs for freezing rain and low probs for 1/2" glaze are posted.

12z/14 EPS consistent on a few inches of snow here many cycles i78 corridor northward on Thursday. Might it end up sleet or ZR? Sure looks nasty Thu night, with as much ice as Monday night I84 corridor. And the flood possible problems associated with short duration heavy qpf, snow melt, ice jammed gutters. Back tomorrow morning.

No additional info from me, at least til 730P. Looks like some tree damage and power outages to me I84 corridor into nw NJ, e central PA. No science on power outages. Should know a lot more tomorrow morning.

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.

The following 1154AM/14 update is for those concerned about power Monday night. The NWS ensemble mean glaze forecast (Sunday more ing update) is out for Monday-Monday night. The blue is 1/2", the dark green is 1/4". If you're anywhere with the dark green/blue, be aware you may not lose power Tuesday morning. This guidance may shift a little northwest on Monday with the southeast edge and total amounts possibly high by 1 or 2 tenths of an inch. Still, this guidance is heftier than what was projected for NC/VA and they got hit pretty hard. Difficult Monday night ahead and results for Tuesday morning may be problematic. My "guess" is a Winter Storm Watch "may" be issued ~330PM, for a Monday night ice storm in the blue area.

And this storm over. Please go the storm threads of 15-16, 18-19. Short term maps get posted in the more substantial event ob threads (longer duration and bigger snow events)

https://www.weather.gov/erh/gis_wfo?id=ALY Slider bar down to the regional and lower right is the map. Updates usually 2 hours after the 330A-330P packages. So the 5A/5P are best for an overall depiction. It updates throughout the day but takes a while for the local WFO amounts to change in the map.

May have been posted earlier, but presume you noticed the 375,000 customers (a little less than a miliion people) without power just n of RDU through southern VA! This was the SPC HREF FRAM ice forecast for the 00z/13 cycle for Saturday. Not too bad. It tend to be a little heavy sometimes, and maybe a bit too cold on the south side. If you look at power outage.us and click the states... pretty impressive. That's what I'll be looking for up here in NJ/PA/NYS/CT Mon-Tue, THU-FRI. So while we had some problem glaze in our sub forum... nothing like southern VA, far north-central NC.

First: 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.

Good morning again, I would like to show you something... the observations from the Sussex Airport (KFWN) which is ~ 4 miles east of our home in Wantage at a little less than 500' elevation. Our home is at 740'. These are the observations in GMT (Z) since about 4AM. Notice the I group showing up around 10 and 11z and yet no defined precipitation in progress. That I group signifies some sort of icing (could be clear sky first, or dense fog ice accretion). In this case while there was some lowered visibility in fog- I think we had a below the radar beam passage of freezing drizzle (shallow low top under 3000' ). It was at this time, that I think the icing developed up here, because at 4AM I didn't notice with a walking check of the back deck. (was reviewing upcoming weather after 4A) There is an interp message of the I group somewhere out in google land. I0003 in the hourly would imply .01 glaze (every 3 = .01) In this case, it tossed out a Trace (I0000) This I group was added to all ASOS's in recent years, after the Cold Regions Research Lab (CRRL) led by Dr Charles Ryerson and Al Ramsay collaborated with several NWS forecasters to see if ASOS could measure ice. This is the best solution that took 15 years to implement but helps forecasters get an automated idea of icing occurrences, primarily for the benefit of aviation but also public products.

So, upon further review, and do check before you go out and fall down, Wantage NJ has a slightest film of freezing drizzle and apparently a few ice pellets from overnight. This includes all surfaces... just couldn't see it at 4A. My guess this occurred at least some of th area south I-84 down to the more obvious icing along and south of I78. 21.4F at the time of this writing. Bust for those who didn't get nary any wintry element and consider yourself blessed with free flow travel - dog walking this morning.

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.

513 AM/14 - 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.

Good morning everyone, This little ice event looks done, excepting remains e LI, and maybe some flurries ne PA, extreme nw NJ and se NYS this morning. HRRR too aggressive ne PA, far nw NJ se NYS. A taste of the mess to come.

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.