Re: Long Range Discussion 20(20) (Ha!)

by mwilli Thu Jan 14, 2021 10:24 pm

after reading the above by the 1/22 period if we get a major snowstorm someone will say madonne and I'll sound the alarm

by **algae888** Fri Jan 15, 2021 5:50 am

The block is so strong in the EPO ridge is so far West All the energy is digging into the deep South West and when it ejects out it's getting sheared apart By the very fast Pacific jet/northern stream. What horrendous runs by the models last night. A once in a decade negative NAO And we can't Get Any system to come close to us. We are probably going to have to wait until the nao relaxes a bit To get any kind of amplified system near us

by **heehaw453** Fri Jan 15, 2021 2:08 pm

Euro shows light snow for D6 over the area. This is a powder keg as shown right off the coast. Slightest bit of energy injected into this a little sooner and it'd be interesting. Again with a blocking pattern these types of solutions are much more possible than with a progressive flow. Euro does blow this up just off the coast in the next frame.

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by **aiannone** Fri Jan 15, 2021 4:28 pm

Posted by DT
https://www.severe-weather.eu/global-weather/winter-weather-pattern-forecast-january-2021-usa-europe-fa/?fbclid=IwAR0sWi4Lag2BYA_dX5QapV43u_GdbsEOUjcZY114Tr-4AzYiNf5F6pm57ns

by **billg315** Fri Jan 15, 2021 4:54 pm

I guess one thing to keep in my mind to keep expectations in check is that while all signs are starting to point to colder air around these parts in the coming weeks, colder air does not guarantee abundant snow. It is quite possible to have a cold regime set up and not get a ton of snow with it. So we will have to wait and see how all of this plays out. But we're close enough now that I feel pretty confident we'll see a period of BN temps take hold starting sometime next week. How long it lasts and what type of snowfall it produces . . . who knows. lol. (also keep in mind, normal highs this time of year are about 38* so BN can mean highs in the low 30s, not necessarily a deep freeze with highs in the teens; although those deep freezes are often dry with minimal snow so that's not necessarily a bad thing).

by **amugs** Fri Jan 15, 2021 8:38 pm

@judah47 The historic 1928/1929 winter pattern aims to return, as we head into 2nd half of January 2021, with now blocked Arctic regions after the Polar Vortex collapse https://t.co/YZqDnnCQlG
— Rafael Garcia de Vinuesa (@RafaelRossello) January 15, 2021

by **amugs** Fri Jan 15, 2021 8:52 pm

GFS says take another hit Mr PV

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BSR coming into play in rhe coming week 7days later EC storm threat
http://joe.organicforecasting.com/BsrEar/Bsr/

by **amugs** Fri Jan 15, 2021 9:31 pm

Check this out from EarthLink John Home UK
15 inch snowstorm maps
Top is20th century
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This is 25-27th - match???
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by **TheAresian** Sat Jan 16, 2021 7:35 am

While my eyes aren't what they used to be, I'd say very close but not quite. I don't know how it would impact practical weather, but the anomaly on the east coast looks to be a fair bit farther south on the current map. It looks like maybe Maine on the top map vs NJ on the bottom.

by **heehaw453** Sat Jan 16, 2021 8:42 am

From here are on in January gets colder. The effects of the PV displacement aren't fully known, but the AO state can be quite obstinate for the foreseeable future. Not convinced first half of February is a lost cause around here but that's way out there ATTM...

As the airmass cools it'll be much more conducive to support wide scale snow events, but the PAC (PNA) isn't really going to help with ridging @ z500 allowing for amplification of the short waves. Moreover, the -NAO will be rather anomalous. So you will continue to notice the surface low pressure on models slide west to east instead of moving northeast. Again, that doesn't mean a shortwave can't explode as the flow slows down and it interacts with additional energy.

Upshot for next 10 days
Colder is strong confidence.
Light snow activity moderate confidence.
Moderate snow activity moderate/low confidence.
Large scale snow events low confidence.

by **Frank_Wx** Sat Jan 16, 2021 1:25 pm

GEFS go absolutely bonkers with the blocking in about a week. It’s hard to imagine a -EPO/-AO/-NAO of this magnitude not producing for our area. The storm threat models are hinting at near the 26th may reward our patience...

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by **heehaw453** Sat Jan 16, 2021 2:06 pm

Frank_Wx wrote:GEFS go absolutely bonkers with the blocking in about a week. It’s hard to imagine a -EPO/-AO/-NAO of this magnitude not producing for our area. The storm threat models are hinting at near the 26th may reward our patience...

Definitely Frank. The short wave for the 1/25-1/26 threat is vigorous as modeled and there is enough ridging ahead of it to amplify it somewhat. As modeled this probably wouldn't get squashed, but could produce a significant event. Most of the modeling demonstrates an excellent overrunning surface ideal for a large scale event.

Yes I know Day 9/10, Day 9/10 and we are all sick and tired of the wait... But... This definitely has potential.

by **Irish** Sat Jan 16, 2021 2:25 pm

Frank_Wx wrote:GEFS go absolutely bonkers with the blocking in about a week. It’s hard to imagine a -EPO/-AO/-NAO of this magnitude not producing for our area. The storm threat models are hinting at near the 26th may reward our patience...

Well, considering this far out, TWC has 3-5 inches predicted for the 25th and 1-3 for the 26th for my area. Something to possibly look forward to.

by **rb924119** Sat Jan 16, 2021 2:31 pm

Frank_Wx wrote:GEFS go absolutely bonkers with the blocking in about a week. It’s hard to imagine a -EPO/-AO/-NAO of this magnitude not producing for our area. The storm threat models are hinting at near the 26th may reward our patience...

This isn’t a true -EPO though, Frank. It’s only a poleward ridge in the EPO domain. As modeled, this would dump the main trough in the west, with only residual negative H5 anomalies centered to our northeast, and a likely attempt to connect the western NAO domain ridging with eastern North American ridging further equatorward. This is not a pattern that favors our area, but central and northern New England instead.......IMO.

by **sroc4** Sun Jan 17, 2021 10:45 am

rb924119 wrote:
Frank_Wx wrote:GEFS go absolutely bonkers with the blocking in about a week. It’s hard to imagine a -EPO/-AO/-NAO of this magnitude not producing for our area. The storm threat models are hinting at near the 26th may reward our patience...

This isn’t a true -EPO though, Frank. It’s only a poleward ridge in the EPO domain. As modeled, this would dump the main trough in the west, with only residual negative H5 anomalies centered to our northeast, and a likely attempt to connect the western NAO domain ridging with eastern North American ridging further equatorward. This is not a pattern that favors our area, but central and northern New England instead.......IMO.

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by **heehaw453** Sun Jan 17, 2021 11:38 am

The threat for 1/25 may depend on the transfer to a coastal from the primary. It's D8 still and exactly what plays out is nowhere near being known.

I'm never a big fan of Miller B scenario's around here though. They tend to favor NE more so than here. What this has going for it is a good antecedent air mass laying down a good overrunning surface. So if we can get a good thump before any taint that would be ideal. The ridge in front of the trough is problematic in that it tends to want to lift the ULL north. Even with the good air mass in place there's only so much the mid-levels can hold off the warming. I'm going to stay positive, but certainly guarded.

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by **heehaw453** Mon Jan 18, 2021 2:03 pm

Not much of an update except to say potential continues to exist for next week. Models continue to vacillate on whether or not ULL amplifies and rides the ridge to our north and west. Any such solution would really hurt our chances of cashing in one or more multiple waves that will rumble through to the east coast as it'll kill our air good air mass.

The only thing I have high confidence in is a good antecedent air mass and a significant block over Hudson Bay. Both of these are very favorable conditions for wintry weather. What makes me skeptical of big snows for the I95 (DC-BOS) right now is the -PNA. It's not an absolute but you definitely want a +PNA when talking about significant snow events for the I95 and surrounding areas.

Because of that I'd set my expectation to light to possibly moderate event next week. Not a feeling a shutout though... At least until tomorrow's runs. Surprised

by **Snow88** Tue Jan 19, 2021 1:49 am

Euro is beautiful for Philly North for the 26th

by **billg315** Tue Jan 19, 2021 8:14 am

I think the setup for Monday night into Tuesday, if taken off the models verbatim at this point -- which is always dangerous and foolhardy 6 days out -- would give me and points north of me about 2-4" before a mix or changeover to sleet, frz, and maybe rain. Definitely need to keep an eye on it not necessarily for "big snow" potential, but if it goes into the Tuesday AM rush-hour, even with a change to sleet/frz rain, it could pose some problems.

by **billg315** Tue Jan 19, 2021 8:24 am

Euro seems overly aggressive on snowfall totals for this type of event, and the GFS is maybe underplaying a bit. So I think a happy medium right now of a few inches before a changeover is the best takeaway at this time. Now areas north of NYC metro and far NW NJ -- where the cold air will be even more entrenched, could perform better on the snow end. Again, assuming the models hold for the next 6 days.

by **sroc4** Tue Jan 19, 2021 8:54 am

billg315 wrote:Euro seems overly aggressive on snowfall totals for this type of event, and the GFS is maybe underplaying a bit. So I think a happy medium right now of a few inches before a changeover is the best takeaway at this time. Now areas north of NYC metro and far NW NJ -- where the cold air will be even more entrenched, could perform better on the snow end. Again, assuming the models hold for the next 6 days.

We shall see Bill. Im not convinced a changeover is the concern here. With the -NAO and -AO firmly entrenched in the pattern I think a sheared out system like GFS depicts, or a system that slides south is more the concern. PNA looks to be strongly neg, and the EPO is meh as we round out the weekend. Nothing to allow nothern energy to dig, and I doubt the southern energy is amplified enough to raise heights out ahead due to the strong blocking in place, therefore IMHO of course it either works out perfect with little to no change over, esp the further off the coast, or nothing much at all. But again its all in the Md to LR at the moment so nothing to get excited/worried about for now anyway.

Meet you in the pool of cautious optimism for a cocktail for the 12z runs.

by **billg315** Tue Jan 19, 2021 9:37 am

Yeah I agree that the “changeover” may not be the biggest problem here, but just one more concern to add to the uncertainty at this point. But hey, at least we tentatively have something to keep an eye on for the moment. Lol.

by **heehaw453** Tue Jan 19, 2021 10:17 am

sroc4 wrote:
billg315 wrote:Euro seems overly aggressive on snowfall totals for this type of event, and the GFS is maybe underplaying a bit. So I think a happy medium right now of a few inches before a changeover is the best takeaway at this time. Now areas north of NYC metro and far NW NJ -- where the cold air will be even more entrenched, could perform better on the snow end. Again, assuming the models hold for the next 6 days.

We shall see Bill. Im not convinced a changeover is the concern here. With the -NAO and -AO firmly entrenched in the pattern I think a sheared out system like GFS depicts, or a system that slides south is more the concern. PNA looks to be strongly neg, and the EPO is meh as we round out the weekend. Nothing to allow nothern energy to dig, and I doubt the southern energy is amplified enough to raise heights out ahead due to the strong blocking in place, therefore IMHO of course it either works out perfect with little to no change over, esp the further off the coast, or nothing much at all. But again its all in the Md to LR at the moment so nothing to get excited/worried about for now anyway.

Meet you in the pool of cautious optimism for a cocktail for the 12z runs.

I'm skeptical of significant accumulations from the initial 1/25 wave too as there just isn't much to amplify it. However, there maybe a baroclinic zone that sets up close by with this and that can enhance totals. The path to a shutout comes with the wave completely washing out which as you said is certainly possible with the lack of any ridging on the backside of it. I'm in the pool of cautious optimism with you, but the antecedent air mass makes me feel we won't get shoutout on this one... I'd much rather have the good overrunning surface than hope for dynamics to help out.

by **phil155** Tue Jan 19, 2021 11:14 am

Glad we have what seems like a legitimate chance at least for some measurable snowfall. Pickings have been very slim thus far this winter and last winter was awful

by **sroc4** Tue Jan 19, 2021 12:24 pm

heehaw453 wrote:
sroc4 wrote:
billg315 wrote:Euro seems overly aggressive on snowfall totals for this type of event, and the GFS is maybe underplaying a bit. So I think a happy medium right now of a few inches before a changeover is the best takeaway at this time. Now areas north of NYC metro and far NW NJ -- where the cold air will be even more entrenched, could perform better on the snow end. Again, assuming the models hold for the next 6 days.

We shall see Bill. Im not convinced a changeover is the concern here. With the -NAO and -AO firmly entrenched in the pattern I think a sheared out system like GFS depicts, or a system that slides south is more the concern. PNA looks to be strongly neg, and the EPO is meh as we round out the weekend. Nothing to allow nothern energy to dig, and I doubt the southern energy is amplified enough to raise heights out ahead due to the strong blocking in place, therefore IMHO of course it either works out perfect with little to no change over, esp the further off the coast, or nothing much at all. But again its all in the Md to LR at the moment so nothing to get excited/worried about for now anyway.

Meet you in the pool of cautious optimism for a cocktail for the 12z runs.

I'm skeptical of significant accumulations from the initial 1/25 wave too as there just isn't much to amplify it. However, there maybe a baroclinic zone that sets up close by with this and that can enhance totals. The path to a shutout comes with the wave completely washing out which as you said is certainly possible with the lack of any ridging on the backside of it. I'm in the pool of cautious optimism with you, but the antecedent air mass makes me feel we won't get shoutout on this one... I'd much rather have the good overrunning surface than hope for dynamics to help out.

Agreed. I’m pretty confident baroclinicity will factor into the equation for sure. We need to monitor where the boundary layer sets up. That will be key to the set up IMHO.

Too far north= Papa bear warm air invades. Too far south = Momma bear cool and dry. Ideally we want Baby bear....just right, where the boundary layer is draped south of Long Island, but not too far, with a weak wave of Lp that passes south of Li on an E to ENE trajectory.

Again I think, but I don’t know, but I think the pattern is such that the wave that develops will be on the weaker side, which we want, because the strength of the -PNA keeps the energy from consolidating too much stringing it along as it traverses the Plains. So long as the boundary layer is set up appropriately this could work. Let it hit the coast and be enhanced by the Atlantic. I’m not looking for a blockbuster event. Simply a light to mod accumulation. Back to the pool.

by **heehaw453** Tue Jan 19, 2021 1:59 pm

12Z Euro continues to put out just < 1" of liquid. It moved it toward DC and Baltimore this run. It's looking less likely the ULL making it to Michigan and more likely it stays under us. The question becomes how far does the ULL get because it does have Atlantic Ocean moisture that it's connected to at the 700 mb. This tells me if you're in the right spot then significant snow is on the table. Expect this to bounce around but the key in my mind is how does the TPV affect this?

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by **amugs** Tue Jan 19, 2021 2:42 pm

Look at that east to west vortices, my God.
Overrunning event.

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