JANUARY 19TH-20TH STORM THREAT

algae888 wrote:

Frank_Wx wrote:I've seen the 12z NAM and 12z ICON (German) models so far today. At the 500mb level, the 12z NAM trended slightly unfavorable with showing a faster southern energy, which allows for more interaction with the TPV. HOWEVER, the NAM is also one of the coldest models with this storm. Washington DC starts to snow Saturday afternoon. The cold air is very entrenched with the High Pressure over us. It would probably be a 4-8" front-end thump before changing to rain, verbatim. But the long range NAM should be taken with a grain of salt anyway.

The ICON, on the other hand, is scary. The snow map is picking up on a lot of ice. See below. This model trended favorably at 500mb.

So far, we are 1-1 with the 12z model suites and 2-0 if you consider the front-end thump on the NAM to be a win.

Frank I think you're incorrect on the German icon it did not count any sleet or freezing rain as snow if you scroll through each frame you'll see that once the precipitation is liquid it doesn't show any additional accumulations for our area check again I'm using tropical tidbits

The snow map I posted is from StormVista. Here is TT's snow map of the 12z ICON, which is a pure snow map.

Irish wrote:Hey all, just joined the crew here because I'm a winter weather nut!  I've been following all your updates on this possible beast coming this weekend, hoping for more snow than rain.  Thx for the updates and keep 'em coming!

Irish

Welcome aboard!!! So glad to have you!! Enjoy the ride hahaha

Irish wrote:Hey all, just joined the crew here because I'm a winter weather nut!  I've been following all your updates on this possible beast coming this weekend, hoping for more snow than rain.  Thx for the updates and keep 'em coming!

Irish

Welcome!!

This potential redevelopment off the Delmarva will keep me up model hunting...dammit guys its been busy at work and i need to sleep!!

amugs wrote:Frank this is the money shot right now fro the NAM: kill the Primary in Tenn and bang its over not a chance in hell you get a warm air push with that cold over head into our area up here. Hope it holds or trends better

Not sure if this is fact or fiction yet, but if it’s fact, definitely a game changer. Also, the NAM’s jet structure seems off to me, and I expect it to correct. This explains why its QPF field is lackluster, as it currently supports multiple pulses of precip instead of one main one.

rb924119 wrote:

Frank_Wx wrote:I've seen the 12z NAM and 12z ICON (German) models so far today. At the 500mb level, the 12z NAM trended slightly unfavorable with showing a faster southern energy, which allows for more interaction with the TPV. HOWEVER, the NAM is also one of the coldest models with this storm. Washington DC starts to snow Saturday afternoon. The cold air is very entrenched with the High Pressure over us. It would probably be a 4-8" front-end thump before changing to rain, verbatim. But the long range NAM should be taken with a grain of salt anyway.

The ICON, on the other hand, is scary. The snow map is picking up on a lot of ice. See below. This model trended favorably at 500mb.

So far, we are 1-1 with the 12z model suites and 2-0 if you consider the front-end thump on the NAM to be a win.

I think the NAM looks generally fantastic, Frank. As long as the energy in the northern stream gets ahead of the southern stream (which it clearly does on the NAM), a large portion of our area will be ok in terms of remaining frozen and not turning wet. That will keep heights suppressed and the flow more W-E than N-S.

The NAM was fine verbatim. It would have brought the area widespread 4"+ snow accumulations.

I was paying more attention to the interaction between the southern energy and TPV, and if you compare that against 06z NAM, I thought there was more of it.

ALL - here is the scary ice ice baby scenario that I hate to say IF it ever happens it would cripple us:
So JUST CHILL and DON'T FLIP - it is one model run - we need about 2 more days of this to hone this in

rb924119 wrote:

amugs wrote:Frank this is the money shot right now fro the NAM: kill the Primary in Tenn and bang its over not a chance in hell you get a warm air push with that cold over head into our area up here. Hope it holds or trends better

Not sure if this is fact or fiction yet, but if it’s fact, definitely a game changer. Also, the NAM’s jet structure seems off to me, and I expect it to correct. This explains why its QPF field is lackluster, as it currently supports multiple pulses of precip instead of one main one.

Yup if it kills it there and redevelops off the coast as it shows then whole another ball of wax rb - you'll have to give us a 3 page report on this LOL!

rb924119 wrote:

Irish wrote:Hey all, just joined the crew here because I'm a winter weather nut!  I've been following all your updates on this possible beast coming this weekend, hoping for more snow than rain.  Thx for the updates and keep 'em coming!

Irish

Welcome aboard!!! So glad to have you!! Enjoy the ride hahaha

Thx, I know I will! I love nothing more than folks who love winter weather, like me, geek out about impending storms!!

Frank_Wx wrote:

Irish wrote:Hey all, just joined the crew here because I'm a winter weather nut!  I've been following all your updates on this possible beast coming this weekend, hoping for more snow than rain.  Thx for the updates and keep 'em coming!

Irish

Welcome!!

Thx

rb924119 wrote:Scott, you don’t want the phase here. Secondly, you don’t need the phase to get the cold. We need the northern stream energy to get ahead of the southern stream. That’s all. That will both sufficiently dampen the height field over the Eastern U.S. and provide the fresh injection of cold air further south.

We need what happened last storm

The 12z GFS is extremely amped with the southern energy compared to 06z. This result in warm air advection entering our region and turning precip from snow to rain. Maybe 1-3" of snow before the change to rain. So far, the GFS looks nothing like the NAM/ICON.

amugs wrote:

rb924119 wrote:

amugs wrote:Frank this is the money shot right now fro the NAM: kill the Primary in Tenn and bang its over not a chance in hell you get a warm air push with that cold over head into our area up here. Hope it holds or trends better

Not sure if this is fact or fiction yet, but if it’s fact, definitely a game changer. Also, the NAM’s jet structure seems off to me, and I expect it to correct. This explains why its QPF field is lackluster, as it currently supports multiple pulses of precip instead of one main one.

Yup if it kills it there and redevelops off the coast as it shows then whole another ball of wax rb - you'll have to give us a 3 page report on this LOL!

So I wasn't going crazy...the NAM (again...clown range for NAM but still) is possibly looking at redevelopment off the coast. That is what I saw there? That would be many different levels of interesting.

Here is how I interprest the NAM.  The energy on the apex of the PNA ridge is actually dampening the amplitude of said ridge.  The result is a more progressive W to E flow to both S system and TPV at this time frame such that the LP tranjectory conts as indicated by the arrow and exits the coast near the area I have circled.  Given the dampening of the PNA ridge, which in the past has not favored us, this time because our S energy is out in front the N energy would catch up to it and begin the phase also right around the time the surface LP is reaching the coast at that Lat.  IF this were correct the surface LP then rapidly intensifys and begin its track more NE rather than ENE which would in theory bring it near the BM.  Again this is all conjecture and what could be, but that energy crashing the WC affecting the amplitude of the Ridge out there could be a key player here

Ugly

With such a sharp temp gradient of possibly 20-30 degrees within 20 miles or so, could this possibly produce lightning?

bobjohnsonforthehall wrote:With such a sharp temp gradient of possibly 20-30 degrees within 20 miles or so, could this possibly produce lightning?

The chances of thunder and lightning are higher than normal. Lots of instability in the atmosphere with strong jet streaks to our north and south, and a banana High to our north compressing heights.

The 12z UKIE is good. Looks like it could be 4-8 inches. Gotta wait for better maps to come out.

Frank_Wx wrote:Ugly

I cant imagin the surface matches with the upper levels here Frank. At 500mb the best PVA should be where I have the circle. At 250 the best surface convergence should also be within the circle I have. (R rear quadrant to the jet streak).

Im not buying it

There is too much phasing Scott. PAC energy tries to phase in Sunday morning and the TPV is far enough south where its having a lot of influence on the southern energy. There is 3 pieces of energy verbatim on the GFS

one thing I noticed so far today is that this system has speed up on all guidance. which is good imo as the front end snows should be good. so far all three global, gfs icon and cmc give nyc 4+ inches and cp and doc around a foot before any change to some other form of precip.

amugs wrote:ALL - here is the scary ice ice baby scenario that I hate to say IF it ever happens it would cripple us:
So JUST CHILL and DON'T FLIP - it is one model run - we need about 2 more days of this to hone this in

dear lord not freaking but that is insane and I am amount tons of others in the bullseye for 1.5 plus. Never seen that b4 I'm sure it would not be fun. No way ur gonna even b able walk outside unless u god ice pik boots.

algae888 wrote:one thing I noticed so far today is that this system has speed up on all guidance. which is good imo as the front end snows should be good. so far all three global, gfs icon and cmc give nyc 4+ inches and cp and doc around a foot before any change to some other form of precip.

Not good IMHO it gives the southern energy and the northern energy more time to phase which WE DO NOT WANT. We want the northern energy way out ahead to act as a kicker. It’s the opposite of what we usually want

Hi all, decided to come out of hiding for this one. Been lurking around but obviously as you all know it's been a disappointing start to the season so far (although my area did get about 11 inches from that Nov 15 storm).

One thing concerning me is the models seem to consistently giving my area (Hopatcong, NW corner of the state) an outlandishly catastrophic ice accumulation. I will say if the current predictions even verify by 50% of what's being predicted my area would be absolutely devastated. So many trees and old infrastructure up here. My house lost power for a week last year due to one of the Nor Easters that swung through.

I am also supposed to be going into NYC on Sunday for a Broadway play. I'm told these are rarely cancelled due to weather. But it's looking like I may have to stay home now.

rb924119 wrote:Scott, you don’t want the phase here. Secondly, you don’t need the phase to get the cold. We need the northern stream energy to get ahead of the southern stream. That’s all. That will both sufficiently dampen the height field over the Eastern U.S. and provide the fresh injection of cold air further south.

That's what rayno was saying yesterday too

Frank do you feel at this juncture a ice storm of that magnitude for 95 corridor is actually feasible? And if so would that be all we get just freezing rain or would we see snow too. In the map mugs posted does that frz fall before or after snow or the whole time? And when approx?

Sorry for a bajillion questions in one message. People are asking me which means media must be talking about ice threat.