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OT: Significant Winter Storm Likely on Thursday (2/18)

RU848789

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Jul 27, 2001
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Metuchen, NJ
Last gasp for the current cold/snowy pattern? Could be. The Thursday event has been trending snowier on all of the global models for the last 24 hours and for the last 12 hours we've had general global model consensus (Euro, UK, GFS, GFSv16, and CMC) on a significant (3-6/4-8") snowfall for most of the Philly-NJ-NYC area, as this system (the one coming ashore and hammering the Pac NW now and forecast to dive down to the southern US to bring another big round of snow/sleet to the Southern Plains and Ohio Valley and freezing rain to parts of the SE US, following the huge trough across the central US) is now forecast to take a further SE track for us, bringing less warm air in initally.

The storm was originally forecast to cut just inland of our area, bringing mostly rain and warm temps, but today's 12Z (7 am EST data inputs) models are now showing the storm likely staying just offshore keeping the cold air in place for most of the event. Some models still show substantial sleet along and SE of 95 (which would reduce snow depth, but not frozen mass) and rain towards the coast after a dump of snow, but most show mostly frozen precip for the event (the GFS is the outlier showing temps warming up to near 40F with heavy rain after 3-6" of snow, but the GFS is known to have a warm bias).

We're still 45-48 hours from the start of the event very learly Thursday morning (which would go until very early Friday morning), so things can still change somewhat, i.e., the track could go back to being further NW with less snow/more rain or it could move further SE with less precip/snow NW of 95 and mostly/all snow down to the coast. A complete miss is looking very unlikely at this time. Don't have time for model maps; if interested, take a look at the Pivotal site or the 33andrain thread.

https://www.weather.gov/phi/
https://www.pivotalweather.com/model.php?m=ukmet&p=sn10_024h&rh=2021021512&fh=96&r=us_ma&dpdt=&mc=#
https://www.33andrain.com/topic/2024-stretch-to-remember-mid-february-2021-wintry-events/page/102/
 
NWS-Philly with a nice discussion. They're also seeing a decent front end thump of snow, with perhaps not much in the way of rain or a warm-up at the end of the event, especially NW of 95 I imagine they'll put out snowfall maps with their 4 am package, as they're a bit preoccupied with the freezing rain potential tonight.

Thursday: A rather nice (if you like wintry weather) sfc
configuration will be in place over our area on Thursday with a
robust cold high positioned north of the area, with the resulting NE
flow creating a nice CAD setup. However, the upper-lvls will be a
bit less favorable, with the the H5 trough-ridge configuration being
shifted a bit west of the "textbook" positioning. This results in a
slightly more westward track of the surface/850 lows, with the
consensus track of the sfc. low being just offshore of the NJ coast
on Thursday night, while the 850 wave would pass overhead.

All that being said, the trend over the last couple days has
definitely been colder with this system with the east coast ridge
trending flatter and the northern High trending stronger with each
guidance cycle. Consequently this setup would likely result in a
general thump of snow Thursday morning into early Thursday
afternoon, before warmer air arrives aloft and we see ptypes
transition from S-N to sleet/freezing ran/rain Thursday afternoon
into Thursday night. The main questions now are how long-lasting and
powerful that initial "thump" of snow is, and also how quickly the
column warms . Given a solid 600-700mb FGEN signature in the warm
advection regime, along with increasing UL divergence in the right
entrance region of the northern jet, would not be surprised if the
initial snow-thump packs a punch, and many locations could pick up
several inches of snow fairly rapidly on Thursday. Given the robust
CAD setup would also not be surprised if many locations NW of I-95
never get above freezing and thus see only frozen precipitation
during the entirety of the event. This scenario would also largely
alleviate any hydro concerns as the warm temperatures/rain would not
fall on the areas with the healthiest snowpack.
 
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NWS-Philly with a nice discussion. They're also seeing a decent front end thump of snow, with perhaps not much in the way of rain or a warm-up at the end of the event, especially NW of 95 I imagine they'll put out snowfall maps with their 4 am package, as they're a bit preoccupied with the freezing rain potential tonight.

Thursday: A rather nice (if you like wintry weather) sfc
configuration will be in place over our area on Thursday with a
robust cold high positioned north of the area, with the resulting NE
flow creating a nice CAD setup. However, the upper-lvls will be a
bit less favorable, with the the H5 trough-ridge configuration being
shifted a bit west of the "textbook" positioning. This results in a
slightly more westward track of the surface/850 lows, with the
consensus track of the sfc. low being just offshore of the NJ coast
on Thursday night, while the 850 wave would pass overhead.

All that being said, the trend over the last couple days has
definitely been colder with this system with the east coast ridge
trending flatter and the northern High trending stronger with each
guidance cycle. Consequently this setup would likely result in a
general thump of snow Thursday morning into early Thursday
afternoon, before warmer air arrives aloft and we see ptypes
transition from S-N to sleet/freezing ran/rain Thursday afternoon
into Thursday night. The main questions now are how long-lasting and
powerful that initial "thump" of snow is, and also how quickly the
column warms . Given a solid 600-700mb FGEN signature in the warm
advection regime, along with increasing UL divergence in the right
entrance region of the northern jet, would not be surprised if the
initial snow-thump packs a punch, and many locations could pick up
several inches of snow fairly rapidly on Thursday. Given the robust
CAD setup would also not be surprised if many locations NW of I-95
never get above freezing and thus see only frozen precipitation
during the entirety of the event. This scenario would also largely
alleviate any hydro concerns as the warm temperatures/rain would not
fall on the areas with the healthiest snowpack.

We've now had 24 hours of pretty strong model consensus on a significant winter storm for the area starting around just before sunrise Thursday (about 54-60 hrs from the model initialization point for the 0Z runs that just came out) and lasting into early Friday morning. Every global model is showing a 3-6/4-8" event for almost the entire Philly-NJ-NYC area, with some potential for sleet to mix in, especially along and SE of 95, and for rain to be an issue for the immediate coast (but not in all models).

While the global models are all showing most of the 0.7-1.0" of total precip (liquid basis) being snow, the NAM (shorter range mesoscale model) is showing 2" of total precip (maybe 5" of snow, 3" of sleet, which is equivalent to 10" of snow, 0.4" of freezing rain and then a little rain on top). I don't say that because it's going to happen, I say it because that's why most people ignore the NAM beyond 48 hours or so - it's an insane solution not supported by any other models.

Anyway, still a ways to go, so changes are still quite possible. It could still end up being a lot wetter, especially for 95 and SE of there, while it could also end up being further offshore with not much to the N/W, a few inches along 95 and several inches or more at the coast. A total rainstorm (like was being shown 3-4 days ago) and/or a total whiff are extremely unlikely right now. Links below if you want to see model output (not the same as models putting out, lol).

https://www.33andrain.com/topic/202...ice-event/page/8/?tab=comments#comment-278477

https://www.pivotalweather.com/model.php?m=nam&p=sn10_acc&rh=2021021600&fh=84&r=us_ma&dpdt=&mc=
 
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We've now had 24 hours of pretty strong model consensus on a significant winter storm for the area starting around just before sunrise Thursday (about 54-60 hrs from the model initialization point for the 0Z runs that just came out) and lasting into early Friday morning. Every global model is showing a 3-6/4-8" event for almost the entire Philly-NJ-NYC area, with some potential for sleet to mix in, especially along and SE of 95, and for rain to be an issue for the immediate coast (but not in all models).

While the global models are all showing most of the 0.7-1.0" of total precip (liquid basis) being snow, the NAM (shorter range mesoscale model) is showing 2" of total precip (maybe 5" of snow, 3" of sleet, which is equivalent to 10" of snow, 0.4" of freezing rain and then a little rain on top). I don't say that because it's going to happen, I say it because that's why most people ignore the NAM beyond 48 hours or so - it's an insane solution not supported by any other models.

Anyway, still a ways to go, so changes are still quite possible. It could still end up being a lot wetter, especially for 95 and SE of there, while it could also end up being further offshore with not much to the N/W, a few inches along 95 and several inches or more at the coast. A total rainstorm (like was being shown 3-4 days ago) and/or a total whiff are extremely unlikely right now. Links below if you want to see model output (not the same as models putting out, lol).

https://www.33andrain.com/topic/202...ice-event/page/8/?tab=comments#comment-278477

https://www.pivotalweather.com/model.php?m=nam&p=sn10_acc&rh=2021021600&fh=84&r=us_ma&dpdt=&mc=
NWS issued snowfall maps, below, with a general 4-6" of snow for most and 6-8" for NWNJ/Poconos/Lehigh Valley, starting around sunrise on Thursday and lasting through the evening. In their discussion, they talk a fair amount about a front end thump of snow, followed by a potential mix or changeover to sleet as far NW as the 95 corridor and maybe even inland of that a bit - as we saw for 12/16, that's very difficult to predict, as is the best banding for snow, but with a track just off the coast, the best banding is often in our NW areas, inland of 95. There's also a risk of a changeover to plain rain, especially near/along the coast (and especially south of 195).

The other big question is how much precip do we get? Most models are showing around 1" of liquid equivalent meaning most of the precip would be snow/sleet, at least along and NW of 95, Still 48 hours out from the start of the event, so changes are clearly still possible, which is why it's not worth diving too deeply into the details of the models or the NWS forecast yet. Suffice it to say that the NWS said they'll likely be issuing warnings at 4 pm, unless there is some major shift in the 12Z models coming out shortly. And FYI, the 12Z NAM just came out and backed off the insane 2"+ of precip from last night with 1-1.5" of precip and almost all of it frozen along and NW of 95 (i.e., (6-12" of snow/sleet with a bit of freezing rain at the end, early Friday) - closer to the other models last night (which are more like 4-8" snow/sleet for most).

https://www.weather.gov/phi/

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So something may happen at some time somewhere? Great modeling. 🤣

It's the middle of the day Tuesday and they can't forecast Thursday morning? SMH. That's why I never understand the weather forecasters.
 
really???? after 3 of 4 busts for you...you touted Tuesday well in advance and omg most did not get one drop of frozen
Seriously? I was downplaying the ice storm threat almost the entire time for everyone south of 78 and that's about how it played out, with some serious ice north of there. Threads are started to highlight risks not as forecasts. Even Sunday's played out perfectly along/SE of 95, but not NW of there, where it was always iffy. And the three significant/moderate snowfalls were all forecasted well.

https://nj1015.com/nj-weather-icerain-storm-exits-next-winter-storm-only-48-hours-away/
 
+1
He has been a bust machine lately.
You are Bac’s biggest ass-kisser on here it’s disgusting!

The two of you are the F’ing worst! If you don’t like to read the information numbers puts on here, then do us all a favor and just don’t read the sh*t!

I go to numbers’ post as my first source of snow forecasting, not to read you kissing Bactotherac’s ass every time he sh*ts all over a post by Numbers.

It’s simple man! Just don’t open the damn post! You only come on here to give him sh*t and it’s annoying as hell to those who just want to see the latest maps and predictions.
 
A couple of you guys are real A-holes. Numbers is providing service that many of us appreciate. He makes it clear that many of these threads are just a heads up and not a forecast. I, for one, thank him. He is right far more often than wrong.
The only way to clean up the threads going forward is to ignore them- not place on ignore, just ignore them. I was trying to do that lately, but I can't stand it when posters blatantly misrepresent something as was the case here. A couple of 10 year-olds teasing people on the schoolyard. They are embarrassing.
 
The only way to clean up the threads going forward is to ignore them- not place on ignore, just ignore them. I was trying to do that lately, but I can't stand it when posters blatantly misrepresent something as was the case here. A couple of 10 year-olds teasing people on the schoolyard. They are embarrassing.
No, people can be banned from threads - when that was done in the past, the trolling stops...although I'd prefer they just act like grown-ups and post useful info, which they're capable of.
 
It's the middle of the day Tuesday and they can't forecast Thursday morning? SMH. That's why I never understand the weather forecasters.
40 years ago we could barely forecast snowstorms 24 hours in advance and now we see all the big ones coming days in advance, even if there are occasionally deviations for some and even busts sometimes. But major busts for an entire region simply don't occur any more (even Jan-15 was still a huge snowstorm from NYC eastward, just not for NJ) like they used to regularly back before the 80s roughly.
 
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