12/26-12/28 Potential Snow Threat

[SnoSki14]

Just going by the setup with the highs in SE Canada, the low to the east of the Apps, I would actually think it would be colder with a transfer further to the southeast. So I wouldn't be surprised if it was at least as cold like the Euro suggests or even a bit colder than that.

If the highs up north were stronger and more cold air was drawn in, we would get a lot more snow and probably a big ice event.

[MJO812]

0z GEFS at 24 hours. This is colder than previous runs.

http://raleighwx.americanwx.com/models/gfsensemble/00zgfsensemblep12024.gif

Then changes to rain for the coast.

[isnice]

Almost Euro show time. Will she bow down to the American models? Or will she stay alongside her foreign counterparts? Major bust potential here that will surely be remembered.

[MJO812]

HPC threw out the GFS and Nam. They said they were too warm.

[isnice]

Ominous silence before the Euro...

[earthlight]

Euro seems to be a tick warmer and farther north but really negligible at this point...could also be a bit faster.

[isnice]

Euro seems to be a tick warmer and farther north but really negligible at this point...could also be a bit faster.

Does the fact that it's faster suggest that the same amount of precip. falls frozen before 850's take over?

[earthlight]

Does the fact that it's faster suggest that the same amount of precip. falls frozen before 850's take over?

Maybe a little more...nothing too crazy. It looks nothing like the NAM thats for sure. Definitely more in the RGEM camp.

[nzucker]

Euro seems to be a tick warmer and farther north but really negligible at this point...could also be a bit faster.

The consensus in the SNE thread was that it was very similar to 12z but perhaps a bit colder, but they're maybe looking at a different part of the storm for a different area. The storm is also faster which may help with a front-end dump before the mid-levels start to warm. Overall, it sounds as if the foreign models are going to win this battle with HPC saying NAM and GFS are running 2-3C too warm in the mid-levels over large regions of the country and the 0z ECM being nearly identical to 12z.

[nzucker]

Maybe a little more...nothing too crazy. It looks nothing like the NAM thats for sure. Definitely more in the RGEM camp.

What would you forecast up here based off this run?

Is this a net gain for snowpack or do we wash away whatever falls?

[earthlight]

What would you forecast up here based off this run?

Is this a net gain for snowpack or do we wash away whatever falls?

It is hard to say especially in your area and Southern New England. There's a pretty good dry slot which could mean a nice thump of snow followed by a period of drizzle. The best lift is definitely in the 3-6 hour period of storm and thats when the mid level warm layer will be straddling your area and northeast through SNE. For areas farther south, it's a quick hitter followed by heavy rain and then a shutdown. I'm expecting an inch here at the very, very most and I forecasted 3-6" for Northwest NJ.

There is a southwest to northeast component to the mid level warm layer over Northern NJ and Southeast NY. So it will be interesting to see if Orange County can really score here.

[RUNNAWAYICEBERG]

been suprised by upton so far. they leave northern fairfield county out of any watches or advisories yet foreign guidance points towards advisory level snows, at the very least, before the changeover. Yet my next door neighbors in brewster are under a watch for several inches with significant ice accum. As a weenie, I know what to expect regardless of what colors upton throws on the map....but the general public, not so much.

[Amped]

Holy thump!!

[Weathergun]

GFS Bufkit shows several inches of snow in the Lower Hudson Valley, down to HPN. If precip starts before 1pm tomorrow, it will more likely be in form of snow in NYC. After that wet-bulb temps get too warm too support snow.

GFS sounding also shows potential for hurricane force wind gusts over Eastern LI tomorrow night. 50kt wind near the surface. And 70kt on top a low-level mixed-layer:

[earthlight]

The Euro has around 3" of snow here on the front end...with 0.50" QPF before the mid level warm layer gets in. Certainly colder than the NCEP guidance.

[snywx]

Wow @ the Euro. Full fledge snowstorm incoming for us NW folk.

[readingaccount1]

The Euro has around 3" of snow here on the front end...with 0.50" QPF before the mid level warm layer gets in. Certainly colder than the NCEP guidance.

Where does that three inch line end? Mercer?

[NYCSuburbs]

Holy thump!!

I wonder how much of that is actually accumulating snow in the south end. Bergen county is very borderline, based on the Wunderground maps temperatures in the south end of this thump are a bit too warm, although I'm not sure how reliable this is as I don't have full access to ECM data.

[jm1220]

GFS Bufkit shows several inches of snow in the Lower Hudson Valley, down to HPN. If precip starts before 1pm tomorrow, it will more likely be in form of snow in NYC. After that wet-bulb temps get too warm too support snow.

GFS sounding also shows potential for hurricane force wind gusts over Eastern LI tomorrow night. 50kt wind near the surface. And 70kt on top a low-level mixed-layer:

The wind and potential for coastal flooding on easterly winds is quite concerning. Hopefully the worst hits near low tide, but the faster storm arrival time is worrisome. Most of us here are pretty much defenseless after Sandy. And we absolutely don't need more power outages.

[nzucker]

Holy thump!!

The 850 freezing line doesn't make its way past Southern Westchester until 30 hours. At 27 hours on the 0z ECM, anyone from I-78 north could be snowing if boundary layer temperatures are cooperating...not sure why the weenie maps don't show the snow a little further south into NJ because the mid-levels look decent. The GFS had .75" of QPF through hour 27...I can't access Euro QPF, but I assume it's similar, which means this is a major front-end thump. If climo prevails, heavy snow goes over to drizzle, or maybe even freezing rain.

Ice could be a threat here as well. The 0z ECM looked a little colder in the boundary layer than other model runs. At 30 hours on the 0z ECM, areas around the intersection of I-287 and I-78 are still right near 0C at 2m even though 850s are above 0C.

BTW, cooling down nicely tonight, currently 27.8/24 in downtown Dobbs Ferry. I could definitely see surface temperatures being stubborn to rise with low dews, heavy precipitation, and NE winds.

[sferic]

So here I am in Liberty awaiting the onset tomorrow.

Am I looking good as in staying all snow, NWS has down to about 8-10 with a possible mix with sleet.

Can we eek out all snow and possibly hit a foot?

The duration, are we talking 8 hours, 12 hours how long of steady precip can I expect?

Then of course this weekend to add to it?

[Amped]

I wonder how much of that is actually accumulating snow in the south end. Bergen county is very borderline, based on the Wunderground maps temperatures in the south end of this thump are a bit too warm, although I'm not sure how reliable this is as I don't have full access to ECM data.

I think the surface stays colder than expected away from the immediate coast during the first half of the storm for Bergen county. My concern is a sneaky warm layer between the surface and 850 might change it to sleet. The second half of the storm is when the surface may warm, or at least that's how models usually error.

[RUNNAWAYICEBERG]

So here I am in Liberty awaiting the onset tomorrow.

Am I looking good as in staying all snow, NWS has down to about 8-10 with a possible mix with sleet.

Can we eek out all snow and possibly hit a foot?

The duration, are we talking 8 hours, 12 hours how long of steady precip can I expect?

Then of course this weekend to add to it?

past couple days, all you do is ask imby questions. 10in with a coating of sleet or a foot? you must be on edge tonite, prob wont be able to sleep.....

[sferic]

past couple days, all you do is ask imby questions. 10in with a coating of sleet or a foot? you must be on edge tonite, prob wont be able to sleep.....

you're right !!! lol

[nzucker]

you're right !!! lol

Euro looks like all snow for Liberty based on 850s, but it's a close call. You might flirt with sleet if there are other warm layers.

[jconsor]

This is one of the most difficult storms I can remember to forecast, with such a razor-sharp rain/slop line.

Here's my best assessment:

NY:

SWF (Newburgh, NY): 6-12"

HPN: 2-5"

NYC: Tr-2"

LGA: Tr-1"

JFK: Tr-0.5"

ISP: Tr

NJ:

FWN (Sussex, NJ): 6-12"

MMU (Morristown, NJ): 3-6"

TEB: 1-4"

EWR: Tr-2"

CT:

DXR (Danbury, CT): 4-8"

BDR: 1-3"

MMK (Meriden, CT): 3-6"

HVN: Tr-2"

GON: Tr-1"

[Edge Weather]

I typed the following and posted this on my blog, prior to viewing the snowfall map that is posted on Accuweather for the 0z Euro. The snowfall map for the Euro on Accuweather is EXACTLY as I stated the following on my blog, and the map there was posted only after I typed and posted the following....The European model is not budging one bit, so neither am I, in fact, I really concerned that this could be a tremendous quick hit type of snowstorm, where there could be EXTREMELY heavy snow falling over a rather short period of time that has the potential to drop up to a foot of snow in only about 6 hours. This would mean near blizzard conditions in many areas if this really occurs as I believe it may in our area tomorrow night. The heavy snow should fall basically from late afternoon through around midnight or so. I think the mistake that is being made by the National Weather Service and many of the other news outlets is that the temperatures will warm up quickly over night, but this should be AFTER the precipitation has lightened up and is basically over. Yes, it will likely end as some drizzle or light rain, but prior to that, I strongly believe the EXTREMELY heavy precipitation rates will keep the atmosphere cold enough for snow in most areas of Northern New Jersey, with the only exclusion being the city areas such as Newark, and possibly north through Eastern sections of Bergen County and Hudson County, close to the Hudson River, where temperatures may be just warm enough to turn the snow to rain after a couple of inches falls. In fact, down by Newark, there may be very little if any snow, but as you head west and go up the hills into areas such as West Orange and Livingston, I can easily picture 6-12 inches. So to try and draw a line of what I am thinking, basically I believe that Eastern Essex County, Hudson County, and Eastern Bergen County will likely get 3-6 inches, except 1-3 inches in the city locations and right along the Hudson River, and Western Essex County, Southern Passaic County, Western Bergen County, Southeastern Morris County and Warren Counties will receive 6-12 inches, and Sussex and Northern Passaic Counties should receive 12-18 inches. I believe this to be a very dangerous situation for anyone considering traveling tomorrow night and I would caution against being on the roads tomorrow late in the afternoon or at night. To reiterate, I believe the National Weather Service and the news outlets are drastically underestimating the heavy snow potential with the storm, and I can easily picture many areas getting nearly a foot of snow in only about a 6 hour time period late in the day tomorrow. I strongly believe they are misreading this situation and that the warm air will not move into our area until after the precipitation is basically finished.

[CooL]

NAM not letting go with the warm air making its way in, all rain for all of NJ. Crazy to see major differences in just 12 hrs compared to the euro. Unless im delusional or just reading the map wrong

[Dark Energy]

WRF has been known to torch it. I know with the xmas eve system, it had all rain for nyc and they had more snow than expected.

[Dark Energy]

plus, the 00z WRF was too warm at h85 per HPC. The 6z NAM would use the 00z NAM as a first guess given there are no RAOBs ingested.