January 24-25: Miracle or Mirage

[stormy]

My 10 pm Sunday prediction has evolved to a 100% verification score with the inclusion of the GFS and GEM  det.

For Augusta County, the 7 am Kuchera  model/ensemble blend is 18.2 inches from 4 pm Sat. - 6 pm Sunday.  The 10:1 blend is 10.2 inches. 

IMO, we have reached a peak of prediction.

Strong hp up north is still a suppression possibility.

The greatest threat during the next 3 days is a downside default because this storm does not fit into 6 month pattern reality. Pattern recognition can be very important in weather forecasting. PSU has said recently that we have wasted many opportunities this winter and that is a disappointment.

Here's hoping that everyone is thrilled come Monday morning.

[IUsedToHateCold]

After the past several years I can't really be too worried about a north trend - I've seen way too many systems get too suppressed and pound the south with a foot of snow while we smoke cirrus. To be honest I hope the setup doesn't allow for that this time. I'd rather see the Hoco-Moco bullseye than even a maximum in my yard, because that's how the big ones go. 

[WxMan1]

Nice to see the 06Z ECMWF look like what the AIFS was showing yesterday. A couple things come to mind for this veteran meteorologist (ugh, I can't believe I said that, but I am in my mid 50s now ).

1) I used to live in Central and Southern VA. As much as I would be excited about those snow totals, it would be difficult to believe given the op model trends towards the EC AIFS. Meaning a high likelihood of a transition at some point. That would put the max snow farther north, maybe even north of me (Crofton) and in the traditional max climo areas N and W of DCA when all is said and done.   

2) I wouldn't get hung up on SLR just yet. It is VERY difficult for this region to vastly exceed 10 or 11 to 1 with abundant moisture and intense WAA within 850-700mb. While 850mb temps should remain plenty cold, it's the warm nose between 750-700mb that could eventually cut down on the flake size. Remember, you want to have your temps below -10°C (between -12 and -18°C) within the layer of deepest ascent, otherwise known as the dendritic growth zone or DGZ. 

Based on climo given that surface low track, I would suspect the best SLRs to be closer to 12-14 to 1, and more likely N and W of DCA, i.e. Dulles to Westminster.

[CAPE]

Latest AFD from Mount Holly-

Signals in the upper level pattern by late week and the weekend becomes quite active between the northern and southern stream jets. The key elements embedded in these features are currently located over the Arctic and the Pacific Ocean, so it`ll likely take at least a couple more days for guidance to have a good handle on this system. However, almost all available guidance depicts an area of low pressure developing near Texas Friday before tracking eastward along the Gulf coast into Saturday. Beyond Saturday there still remains forecast uncertainty regarding the details of how this system will play out for the east coast. However, at this time most forecast guidance tracks the low north and east towards the North Carolina coast and then off to the north and east from here by the Sunday into Monday time frame. This track puts the mid Atlantic region on the northern side of the system with the main question then becoming just how close to us does the low track. There will be a very strong and broad arctic high to our north and some of our prior guidance had suggested this may be strong enough to suppress the system just south of the area. But over the past 12 to 24 hours there`s been a general trend northward in guidance suggesting the precipitation shield will make it into our area. In fact, snow probabilities of the NBM now show a 60-70% chance of 2+ inches of snow and a 40-60% chance of 6+ inches of snow for areas roughly along and south of the I-95 corridor with decreasing probabilities farther north. These probabilities are higher than with the prior forecast cycle. So while this system still is about 5 days out, the signal for a winter storm to impact at least parts of the area is higher than usual. The timing of this would be as early as very late day Saturday continuing through Sunday and potentially even lingering into Monday depending on the system`s speed.

[wxdude64]

18 minutes ago, Nomz said:

I’d like for models to work their way a little north today but I’m just feeling greedy. I’ll take the 1 inch qpf in DC at 10:1+ ratios

 

12 minutes ago, Terpeast said:

Careful, we don’t want too much too fast. I am 90% sure the storm will come up north anyway. I’m thinking the mix line will reach as far north as EZF/SoMD despite the models saying it’ll stay south of the NC/VA border. 

 

7 minutes ago, snowfan said:

Its Tuesday, pace yourself. No one in the DMV should be clamoring for north movement just yet.

100%. It is FINE where it is currently, you want it north WHEN THE STORM STARTS (or last run before precip starts) not 4-6 days out. It starts north now and by day 4 you are a cold rain while NYC is basking in 15" of snow. 

[EstorilM]

18 minutes ago, Nomz said:

I’d like for models to work their way a little north today but I’m just feeling greedy. I’ll take the 1 inch qpf in DC at 10:1+ ratios

Low sat night out here is 12, high Sunday is only 19. DC will be a bit warmer, but I’d expect ratios way above 10.

 

I suppose it’s a safe bet to stick to 10:1 the way things go around here. 

[Interstate]

2 minutes ago, EstorilM said:

Low sat night out here is 12, high Sunday is only 19. DC will be a bit warmer, but I’d expect ratios way above 10.

 

I suppose it’s a safe bet to stick to 10:1 the way things go around here. 

Why... just because it is cold at the surface... Doesn't mean there will be a warm layer up high.

[Maestrobjwa]

1 hour ago, CAPE said:

Latest blend. I think we got us a solid signal across guidance for a major winter storm lol

Don't think we've seen that much pink on an NBM since it started, lol (when did it launch, btw?)

[Paleocene]

FYI weenie alert for weenies - pivotal weather offers a one week free trial of their geographically zoomed, detailed maps (and access to 06z and 18z euro detail maps). I just signed up. Best week of the year to do that lol, but it does require a credit card. 

Something I'll be watching over the next 48-72 hours... 850mb and 700mb temperature and wind direction, if and when the low transfers. This image is from the 06z euro, the low is popping off the NC coast.  Can the cold press win? If we're gonna get the juice, we may flirt with the heat. 

 

[LP08]

WAA snows are not the best ratio producers even into super cold air masses until the favored zones.  Been here too long to rely on anything above 10 or 11-1.  Best ratios as always are in a CCB or ULL pass.  Stick with 10-1 and adjust higher if needed.

[clskinsfan]

Euro run this morning is amazing. One thing I love about this setup is even if the phase fails we are going to get the  WAA part of this through our area. Yes it would be a smaller storm then. But it is nice knowing a full failure is pretty much off the table thos far out. It's gonna snow yall. And I feel bad for the people to the south getting that horrific ice storm. Multiple days without power due to infrastructure damage during an arctic outbreak is no fun. 

[H2O]

23 minutes ago, Terpeast said:

Careful, we don’t want too much too fast. I am 90% sure the storm will come up north anyway. I’m thinking the mix line will reach as far north as EZF/SoMD despite the models saying it’ll stay south of the NC/VA border. 

I said this yesterday before this thread was started.  If the euro phase does happen then suppression is gone and it will be more adjusting north over time.  That opens the door to warm noses punching in.  The mix line already shifted north bigly.  So now the places that looked solidly all snow for the duration will get pingers which always gets up to DC.  North crew is greedy and will be happy while DC south sleet.  Warm layers always go in more than modeled.

[Paleocene]

3 minutes ago, clskinsfan said:

Euro run this morning is amazing. One thing I love about this setup is even if the phase fails we are going to get the  WAA part of this through our area. Yes it would be a smaller storm then. But it is nice knowing a full failure is pretty much off the table thos far out. It's gonna snow yall. And I feel bad for the people to the south getting that horrific ice storm. Multiple days without power due to infrastructure damage during an arctic outbreak is no fun. 

Yeah, I know there are lots of caveats with ice maps. But holy smokes.

[Ji]

I was going back and reading articles from Last February storm. The storm was to take place on Feb 20th. We peaked with fun on Friday the 14th. Most models had 1-2 feet of snow. The AI was never really on board. On the 15th...there was a very slow bleed south and east but we didnt think much of it till the 00z runs that night. the 16th was a disaster. We were down to a 6-10 inch storm if everything went well. The 17th....it got worse and worse but the actual rug pull started on the 15th. 5 days before the event

[blizzardmeiser]

2 minutes ago, H2O said:

I said this yesterday before this thread was started.  If the euro phase does happen then suppression is gone and it will be more adjusting north over time.  That opens the door to warm noses punching in.  The mix line already shifted north bigly.  So now the places that looked solidly all snow for the duration will get pingers which always gets up to DC.  North crew is greedy and will be happy while DC south sleet.  Warm layers always go in more than modeled.

so the slower it goes, the more amplified it gets and trends further north. 

[Nomz]

1 minute ago, Paleocene said:

Yeah, I know there are lots of caveats with ice maps. But holy smokes.

Some place, not sure where, is gonna get absolutely smoked by this thing down south. Could be arkansas, could be south carolina.

[GreyHat]

2 minutes ago, Ji said:

I was going back and reading articles from Last February storm. The storm was to take place on Feb 20th. We peaked with fun on Friday the 14th. Most models had 1-2 feet of snow. The AI was never really on board. On the 15th...there was a very slow bleed south and east but we didnt think much of it till the 00z runs that night. the 16th was a disaster. We were down to a 6-10 inch storm if everything went well. The 17th....it got worse and worse but the actual rug pull started on the 15th. 5 days before the event

Hopefully history doesn't repeat. Would like to know the difference e.g. cold, HP placement and strength. 

[SnowenOutThere]

1 hour ago, WxUSAF said:

 

The 0z (and seems like 6z) euro evolution is what I was honking at last night with the 18z run. Long duration events are super rare for a reason, but I’m getting major PD2 type vibes with overrunning and then a coastal. This thing keeps slowing down though so we’re only gaining like 45 minutes on the start time for every hour that passes lol.

The Euro is doing exactly what we wanted it to with my breakdown yesterday. It’s managing to get help with the NS and have a legit HECS on the table. 

[SnowenOutThere]

I’m not going to lie I love where we are at. I’m a little nervous about mixing down at UVA but as long as we don’t see any crazy north shifts today everyone should be fine for a (primarily) cold smoke. All the models have pretty much trended exactly how we want them too as well. Only thing is id love it if we don’t keep pushing this storm back! 

[bncho]

2 minutes ago, SnowenOutThere said:

The Euro is doing exactly what we wanted it to with my breakdown yesterday. It’s managing to get help with the NS and have a legit HECS on the table. 

Is the 6z Euro your "greatness" scenario, or is it not there yet? If not, what do we need to trend towards?

[SnowenOutThere]

Just now, bncho said:

Is the 6z Euro your "greatness" scenario, or is it not there yet? If not, what do we need to trend towards?

No, it petty much is. Though arguably it’s a mix of that and a colder/better oriented scenario 5. 

[StormyClearweather]

10 minutes ago, Ji said:

I was going back and reading articles from Last February storm. The storm was to take place on Feb 20th. We peaked with fun on Friday the 14th. Most models had 1-2 feet of snow. The AI was never really on board. On the 15th...there was a very slow bleed south and east but we didnt think much of it till the 00z runs that night. the 16th was a disaster. We were down to a 6-10 inch storm if everything went well. The 17th....it got worse and worse but the actual rug pull started on the 15th. 5 days before the event

I was just wondering about this last night - thanks for going back and finding it.

I seriously remember being at dinner on Valentines Day and checking the 18Zs (yes, really), and even though it looked fine, you could feel what was about to happen as ECMWF shifted south. 

So if we make it through today... maybe I can actually start feeling some confidence in this thing? 

P.S. My friend the MOGREPS, so this isn't just a banter post: 

[H2O]

3 minutes ago, blizzardmeiser said:

so the slower it goes, the more amplified it gets and trends further north. 

Yup.  What the models showed yesterday with it being mostly NS energy meant a quicker storm with that sliding by first with its WAA that everyone worried about being smushed.  If the NS and SS merge then it slows it all down, allows it to crank, and while the WAA gets more robust it also has a longer SE/E fetch off the oceans.  A strong HP to the north helps but thats only at the very low levels for the coastal plain.  Upstairs the warm layer will smash in to the fall line.  Feb 04 a good example.  Was a nice storm for DC but had sleet for hours until ULL swung thru

[Ephesians2]

27 minutes ago, WxMan1 said:

Nice to see the 06Z ECMWF look like what the AIFS was showing yesterday. A couple things come to mind for this veteran meteorologist (ugh, I can't believe I said that, but I am in my mid 50s now ).

1) I used to live in Central and Southern VA. As much as I would be excited about those snow totals, it would be difficult to believe given the op model trends towards the EC AIFS. Meaning a high likelihood of a transition at some point. That would put the max snow farther north, maybe even north of me (Crofton) and in the traditional max climo areas N and W of DCA when all is said and done.   

2) I wouldn't get hung up on SLR just yet. It is VERY difficult for this region to vastly exceed 10 or 11 to 1 with abundant moisture and intense WAA within 850-700mb. While 850mb temps should remain plenty cold, it's the warm nose between 750-700mb that could eventually cut down on the flake size. Remember, you want to have your temps below -10°C (between -12 and -18°C) within the layer of deepest ascent, otherwise known as the dendritic growth zone or DGZ. 

Based on climo given that surface low track, I would suspect the best SLRs to be closer to 12-14 to 1, and more likely N and W of DCA, i.e. Dulles to Westminster.

I'd be okay with a sleetfest here in Central VA, as long as we get warning level snow first. Would be great to keep the snowpack around as long as possible. 

[BlizzardNole]

That ice map for parts of the south is awful and would rival our 1994 disaster

[SnowenOutThere]

41 minutes ago, Terpeast said:

Careful, we don’t want too much too fast. I am 90% sure the storm will come up north anyway. I’m thinking the mix line will reach as far north as EZF/SoMD despite the models saying it’ll stay south of the NC/VA border. 

Yep. Let’s just get the models to show the same thing they have been for today. 

[BristowWx]

3 minutes ago, Ephesians2 said:

I'd be okay with a sleetfest here in Central VA, as long as we get warning level snow first. Would be great to keep the snowpack around as long as possible. 

SN/IP mix.  you get the best of both.  I have always liked that combo.

[SomeguyfromTakomaPark]

24 minutes ago, Paleocene said:

FYI weenie alert for weenies - pivotal weather offers a one week free trial of their geographically zoomed, detailed maps (and access to 06z and 18z euro detail maps). I just signed up. Best week of the year to do that lol, but it does require a credit card. 

Something I'll be watching over the next 48-72 hours... 850mb and 700mb temperature and wind direction, if and when the low transfers. This image is from the 06z euro, the low is popping off the NC coast.  Can the cold press win? If we're gonna get the juice, we may flirt with the heat. 

 

Also if you use the beta version on the phone you have access to 6Z and 18z euros 

[bncho]

7 minutes ago, SnowenOutThere said:

No, it petty much is. Though arguably it’s a mix of that and a colder/better oriented scenario 5. 

What do you think the cap is for this storm? Why is the Euro solution less snowy than solutions like the UK?

[Ephesians2]

6 minutes ago, Ephesians2 said:

I'd be okay with a sleetfest here in Central VA, as long as we get warning level snow first. Would be great to keep the snowpack around as long as possible. 

also I have 8" on the year and you all have maybe half that, so the likely north trend = reversion to the mean