wdrag

Wantage NJ 4sw: Had mostly r- and some ip- for about 90 minutes but all snow (2mi) now. 0.2" total so far...its wet snow out there but didn't clear. we'll see what we have at 1P. 33.1F. pave wet. 942A

Don't give up on snow in NYC this afternoon. Could get interesting for an hour two around 1-3P.

Let's wait this out... I need to NAM to be more realistically south and closer to EC or GFS. It cant keep trying to drill big snow into the southern Adirondacks.

Hi! Gradient collaborated grids that see adjacent offices and work with together with WPC. So qpf, whether its all snow and the associated mixing ratios dictate snow amounts. These are put together sometimes before new guidance that you and i see and sometimes hastily because of the eastern time zone and 330-4PM/AM deadlines (deadline office dependent). I'd take the lower numbers of the range as a start, and focus on the axis. I want to reserve comment on anything beyond what we see here, til 430 or 5P. Too many models and interps...

Mostly rain here since around 810A in Wantage. at least 0.2" snowfall so far. 33.1F. roads wet.

Need to wait til 4P....thanks

NWS collaborated snow amounts in case this hasn't posted yet... only thru 7A Thursday. Temps will probably be generally 20-25F during the entire snowstorm across nw NJ/seNYS/ne PA and CT.

Tables for JFK/LGA I think attached. Have looked at two day (crossover with the midnight climate... tougher for top 20 depending on where all snow but, MPO seems a best fit... others may too-dependent on track and mix potential. Won't post the two day til late today or tomorrow if that still applies.

First tenth of an inch in Wantage as sleet has changed to snow. Pavement getting slimy and very slippery on wood. 34F. ground white.

I'll add the data shortly... ONE error on my part ... this data is I think driven by calendar day. I may add some two day totals to bring better perspective. Even so, I think top 20 is possible by midnight Wednesday night. It does appear to me a lot of the big FGEN 1-3"/hr has to be before midnight or earlier for LI/I80) south... unless the storm slows and I don't think that will happen. However, I80 ned including LI... i would not be surprised at lagging bands of 1/2MI Snow rolling southeastward after sunrise Thursday as the back side of the comma head moves east (getting what ne PA has all night)--this presuming the EPS is 80% accurate.

Wantage snow and sleet mix east 722A and temp now 34.5. Tinge of white on the roofs.

You'll get there...first a mix of sleet and rain then wet snow and sleet. Not sure if you can accumulate more than an inch or 2 by 2P.

ice pellets at 644A in Wantage NJ

Few small flakes in Wantage NJ.. temps 34-36F around here.

From Topic headline at 6AM Monday 12/14/20. Please monitor NWS Watch-Warnings for this storm and associated statements and still uncertainty on where highest impact. There is/was some overall slight southward shift in the guidance in the past 24 hours and so my uncertainty for the forum is northern CT-Catskills, and LI/I95 southeastward. WPC still has 1.5"+ qpf just s of I80-LI and 3/4" into northern CT. Added the EPS 10 to 1 ratio graphic of both today and Wednesday nights storm. I think that serves as continued good starting point with the usual caveat on the northern and southern fringes. If you have travel plans Wednesday into Thursday I95 northwestward from VA through WV, PA, NJ, NYS and southern New England it's probably a good idea to consider changes, based on your NWS or other favorite media outlet forecasts. I think this will be a top 20 snow storm for a few parts of our NYC subforum (basically ~ 1 foot will prompt that review) but unsure where. For now between I95 to I84. Anticipating (not guaranteed) widespread closures or delays for all transportation systems I95 corridor northwestward Wednesday evening into Thursday morning,. For those who have access and wish to do so, you can calculate an experimental storm index to get an idea of what is probably coming. I don't want to presume more than Major yet (crippling is the next step up). Here is some information. https://www.ncdc.noaa.gov/snow-and-ice/rsi/?nesis Still variability in northward extent of heavy 1 foot snow ranging from the NAM Adirondacks to the GFS-RGEM I80-LI. UKMET is still quite far north. Ensembled r/s line looks to remain mostly south of I80-LI but awfully close, close enough to think sleet, rain or freezing rain mixes in for a time after the initial Wednesday evening thump for LI and s of I80. EPS continues almost unyielding on the widespread 8-18" snowstorm (isolated 2 feet possible in the banding somewhere north of I80-LI). Major power outages possible wherever the 6" of 32-33F wet snow accumulates along with wind gusts of 40-50 MPH. If this were to occur, it would most likely develop between 9 PM and midnight Wednesday evening per consistent modeling of snow onslaught and wind gusts increasing past 30 MPH. Am targeting LI south coast and NJ coast but this will require 6" wet snow (32-33f). Isolated wind gusts above 50 MPH possible on those coasts. Snowfall rates of 1-3"/hr possible in northward transiting bands Wednesday-evening/ night. Where these tend to park on the northern extent of the storm, will probably be the 2 feet of snow, especially with ratios drier than 10 to 1 (maybe 13 to 1). NWS has the multi model ratio blend tool and BUFKIT can assist for those who have that tool. There could be closing bands of moderate snowfall Thursday morning after sunrise into early afternoon as the comma head tends to fold southeastward behind the eastnortheastward departing storm. Clearing the first few inches of snow around 8-10PM Wednesday will make it easier to remove the additional snow Thursday morning. Where it's wet-caution for those with heart conditions., This strong easterly surface gradient (northeast wind) between the cold 1035MB high over Quebec and and the probable 995-1000MB low near Cape May early Thursday will produce minor to moderate coastal flooding, for the Thursday morning high tide cycle. Follow NWS statements. So the base EPS snowfall graphic is added. Also multiple locations of whatever is in their climate database (did not check for missing data). This gives us an idea of amount goals to reach top 20... No guarantee anywhere but I would think 1 or 2 of these would make top 20. May not comment in detail again til late today or this evening, shifting attention to today. Have a good day and fun debating. Am still uneasy about the northward extent of the 00z/14 EPS 1" qpf which is still near the MA Pike.

One event at a time: Today... as per the attached graphics. 1-4" of wet snow ne PA/nw NJ into all of CT. Heaviest probably hills of nw NJ and into ne PA south of I84. It may begin as rain and may end as sprinkles. Intermediate late morning-early afternoon brief periods of 1/2mile moderate snow with accumulation of 1/2"/hr for a couple of hours. Pavements wet except hilly areas above ~ 700 feet. Even NYC could Trace or measure 0.1" this afternoon after 1PM. EC came up quite a bit the past two cycles, the HRRRX went down quite and the SPC HREF stayed steady. Attached the 00z/14 SPC HREF (8 member ensemble) and the 06z 3k NAM 10 to 1 ratio =which may be a bit high on the se edge but it states where I think the potential is best. mPING will be helpful. 35/31 here in Wantage at 505A

Well researched. Thank you... I plan (if it still applies) to reference daily records at CP of 5.3" for the 16th - 1948, and 17th 6.7 in 1932. No promises we'll get either. Gotta rest. Walt

My terrible mistake! I was reading mo to date. Here's what I have for the 17th. Can this work? Just let me know. MY ERROR on the 19.8. Great catch!! Hmmmm... small chance we could break two successive daily records. Almanac for New York-Central Park Area, NY (ThreadEx) December 17, 2020 Daily Data Observed Normal Record Highest Record Lowest Max Temperature M 42 62 in 2000 15 in 1876 Min Temperature M 32 50 in 2015 1 in 1919 Avg Temperature M 36.9 54.5 in 2015 10.5 in 1876 Precipitation M 0.13 2.28 in 1888 0.00 in 2017 Snowfall M 0.1 6.7 in 1932 0.0 in 2019

Closing would help but maybe toss too much warming up to I80 to shave amounts by 6+ inches due to rain-sleet. SST's are a bit of above normal so lapse rates will be enhanced slightly. It seems to me this storm maxes intensity along the s NJ coast Thursday morning and then occludes east or east northeast, with a subsequent weakening of the short wave. This one is digging far enough south into the southern states before turning northeast that it's yanking moisture newd aloft, and the big high in Quebec adds an easterly low level jet flow and lift over the ene-wsw oriented thickness to yield the qpf modeled. I'm good without a stall... this will be very big and may satisfy the daily record snowfall at CP by midnight Wednesday night? (front end thump). Virtually no chance of exceeding the Thursday daily record of 2003 -19.8

I've been out of the forum for 7 hours and coming back to the still south GFS op is a little disconcerting but as many have posted... basically other models north and 12+. Maybe it's somewhere in between...blend and shift south 30 miles? Just can't add anything useful beyond this. By the way, I hope we all have something to post on the Monday thread. It's looking pretty good to me for a swath of wet snow. Will try and update both threads, Monday around 630A. PHI---bold and I think a very smart Watch move. We don't often get 1-2 footers... and even if some of the watch fails, it's a watch. The idea is get public attention with official product and steady the uncertainty a bit. There are multiple facets to this storm... damaging wind and wet snow accumulation with potential for considerable power outages LI and just se of I95, along with moderate coastal flood threat Thursday morning, airline impact and basic travel impacts are potentially very high I95 corridor on up through at least the I84 corridor, and probably up to near I90. Have a good night.

WPC D4 prob 3"+.

Here's some guidance...not gospel. Lets see if this guidance is too cold and less snow occurs NYC area down to I-195 in NJ than shown here. Please use the legends for your area. I definitely think there will be a period or two of 1/2mile moderate snow and 1/2" accumulation/hr in the region near and west of NYC. Decent banding will occur and there is some lift centered in the ideal DGZ. Have a look at the 12z/13 NAM 3k profile for LGA lift and temp. Later, Walt

Fwiw: WPC's first take late this morning on QPF for Wednesday evening into Thu, but does not include prior to 7P Wednesday. This will update early this afternoon.

Absolutely! The questions continue going forward, will it hold? I took a look at the 500MB pattern at 84 hours...modeling a 140 kt jet up over Quebec Wednesday evening and plenty of sw flow back to OHIO at 500MB. I'm pretty sure this says northern solution.

I like hanging out and tryin to provide some insight above and beyond straight model use... but it's still the models. back in the 1970s we could outguess the models 'sometimes', because they only ran 2x/day, fewer models and so we knew the biases. Not so today..,many models updated yearly. For this storm, soon we have to frame actions.. No pressure: I remember my shifts in the office... daytime phones ring off the hook with how much this and that, - that's why it's important to have a venue such as this to sound off and discuss, but also I think there has to be a public product framing these event, to keep things in perspective. I still worry, even on this one, hanging too far out. So far (including 06z EC) we're on track excepting the GFS op and GEFS south.