Post Turkey Day Storm Threat

[Baroclinic Zone]

Pope? Pope? Where's our morning sermon praising the models?

[Baroclinic Zone]

:mapstorm:

[Cold Miser]

I so can't wait to get by this Thanksgiving system.

Yup. Although, I will be up in the North Adams/ Williamstown, Ma. area for T-Day, so there's the chance of some frozen garbage to come.

[Typhoon Tip]

RE the overnight model handling of the erstwhile DEC 1-5 interesting period of time...

Indeed, what a disappointing overnight model series they were – more so the 00z than the 06z as far as the operational GFS is concerned. Considering where we were as of the 18z GFS run yesterday, while songs of the 12z Euro solution played rapsidy in our dreams, those 00z runs were a slap in the face the likes of which would make Mike Tyson circa 1985 jealous. To show that I am not without consciousness in such matters, to those heartened by the weather I will commiserate your grief by stating – Oh, just gosh awful!

But wait! There is still hope. Let's start by going through some recent chronology of model solutions, and than try to analyze the plausibilities.

The 12z Euro run yesterday took an about turn over previous solutions, and showed a system that it was originally taking into Ontario D10 and rathered it a closing OV system, and eventually [probably] an ~ Miller B bomb for Dec 1. Then, duh duh dunnnn, the 18z GFS follows suit and offers up a slow moving yard sticker for the interior. Then, came the dreaded 00z runs, solutions for a different planet, going way waaaay back to western Ontario again! In fact, the 00z Euro went as far as to offer up a southerly gale with DPs of 60+, and probable wind damage of all things. 12z rain --> mix --> blizzard, 00z tropics.

First and foremost we need to remember that this is a Day 6- 10 interval of time that we are dealing with. Pinch your selves ... because that alone makes any consternation over continuity shifts almost laughably unnecessary. I know, I know - this comess with difficulty when we have been collectively salivating over hints and frets for days if not weeks regarding a pattern shift toward wintry paradigm. As a brief digression, we have been putting off the cold arrival since the GFS first flashed in solutions somewhere around the 20th of October. Quite typical to rush in a change; and, considering it was a hemispheric modal change - meaning massively encompassing - you had to figure it would take longer.

The modeling/handling of the –NAO out in time is the culprit for the continuity shift in question. It is being erratically handled by the models. They are all over the place with where to put the blocking ridge, and this then naturally has a huge implication on the orientation of the main storm track.

However, I believe there is a still a decent wintry storm threat for Dec 1-5, but it is going to be coming in and out of focus until shorter terms. The reason I think the threat is still on the table despite these recent runs is because there is a background …quasi-Archambault event suggested in there. The short and skinny on that is: Big mode shifts in the teleconnectors tends to result in large precipitation events over eastern N/A – that’s the basic gist on her research/thesis particularly as it pertains to the cold season PNA. The reasons for that are quite intuitive really; first you establish a large scale temperature and thermodynamic condition, then, in order to change that condition requires large scale synoptic mixing – boom.

That said, there is a diving –NAO (that much has a weighted confidence, much less where) currently, and that combined with a leading –EPO cold dump in Canada should drive negative temperature departures from D4 to D10 – therein is the in situ temp and thermo anomaly that would need to be changed. The erstwhile PNA raises some 1.5SD and combined with the NAO rising, which can be seen in the runs as the ridge dislodging and retrograding through central Canada (a characteristic that the operational runs abruptly and suspiciously abandoned on the 00z runs), that whole scenario really risks stranding significant wave energy as it is passing through the OV. The weakness in the geopotential medium that creates then also helps sever polar vortex vorticity, which comes down and phases in those prior runs.

That problem here is that is all actually an acceptable scenario because it fits with these differentiating teleconnectors. The 00z ECM and GFS runs do not fit this multi-day, multi-cycle, multi-ensemble backed teleconnector signaling.

Now, Of course, we have seen in the past some renegade solution enter the discussion seemingly just to be annoying, and sure enough ...start eerily gaining support until abruptly all guidance collapses that way… Barring that rarity, I think the –NAO ridge morphologies in these runs is just something we have to deal with until shorter terms. Patients.

[moneypitmike]

What a gross day.

HEAVY, HEAVY drizzle; one might even call it light rain. Was just down at the beaver pond and it was coming down hard enough to make the "chiriping" sound on the ice, similar to the sound a stone makes when you skim it off a frozen pond.

Cold and dank. 35.6/34. Get another log for the fire.

[moneypitmike]

That problem here is that is all actually an acceptable scenario because it fits with these differentiating teleconnectors. The 00z ECM and GFS runs do not fit this multi-day, multi-cycle, multi-ensemble backed teleconnector signaling.

Now, Of course, we have seen in the past some renegade solution enter the discussion seemingly just to be annoying, and sure enough ...start eerily gaining support until abruptly all guidance collapses that way… Barring that rarity, I think the –NAO ridge morphologies in these runs is just something we have to deal with until shorter terms. Patients.

Thanks, John. I guess we can continue to watch things unfold and hope for better things in those better defined, shorter term model renditions.

[moneypitmike]

Lol. The GFS has taken our Friday system and made it little more than a shower and maybe a flurry. Maybe I'm missing something.

[Baroclinic Zone]

12z GFS suggests more of a frontal passage with the primary well west and little secondary development until GOM. Could be a brief period of frozen at onset.

[Tropopause_Fold]

12z gfs suggests a very brief window for some light frozen precip over parts of the higher terrain in MA (NW CT?) thursday evening but otherwise, not a big surprise. maybe enough evap cooling to get some sloppy flakes or sleet pellets into CT, RI, E MA?

[moneypitmike]

12z GFS suggests more of a frontal passage with the primary well west and little secondary development until GOM. Could be a brief period of frozen at onset.

There's so little qpf, there really isn't an onset/end. It just kind of "is".

[Tropopause_Fold]

12z gfs suggests a very brief window for some light frozen precip over parts of the higher terrain in MA (NW CT?) thursday evening but otherwise, not a big surprise. maybe enough evap cooling to get some sloppy flakes or sleet pellets into CT, RI, E MA?

if precip could get in faster it would help. column is cold enough early on turkey day but there's so much dry air, it's a catch 22.

[CoastalWx]

32.1F and rain

Sounds like Ray's favorite temp.

[OKpowdah]

There's so little qpf, there really isn't an onset/end. It just kind of "is".

We just need a bit more of a wave along the front to promote overrunning. Still has potential

[CoastalWx]

if precip could get in faster it would help. column is cold enough early on turkey day but there's so much dry air, it's a catch 22.

The NAM suggested good evapo cooling out in NY State, so that would probably apply further east. I could see sleet at the coast, if winds are light e-se and the precip comes in early enough.

[moneypitmike]

We just need a bit more of a wave tsunami along the front to promote overrunning. Still has potential

[Tropopause_Fold]

The NAM suggested good evapo cooling out in NY State, so that would probably apply further east. I could see sleet at the coast, if winds are light e-se and the precip comes in early enough.

yeah the NAM had like -35C tds at 800mb. GFS has a boat load of dry air in the low / mid levels as well so initially the WBZ is GL for a lot of the area so maybe that's enough to get some short-lived flakes or pingers or something. who knows...maybe someone like MRG or Will or something hangs onto some sleet / mix for several hours.

[Baroclinic Zone]

Follow system looks like a cutter as well for the end of the month.

[Tropopause_Fold]

Follow system looks like a cutter as well for the end of the month.

it pops a secondary but it cuts up through SNE...regardless it's day 8-10.

[Baroclinic Zone]

it pops a secondary but it cuts up through SNE...regardless it's day 8-10.

Yeah, just model talk.

[CoastalWx]

yeah the NAM had like -35C tds at 800mb. GFS has a boat load of dry air in the low / mid levels as well so initially the WBZ is GL for a lot of the area so maybe that's enough to get some short-lived flakes or pingers or something. who knows...maybe someone like MRG or Will or something hangs onto some sleet / mix for several hours.

It looks like the setup where the classic areas along the east slopes of ORH...well just north of ORH through sw NH will probably hover near 31 or 32 for hours and then maybe inch to 33 or 34. I've been liking that area of sw NH, but the problem is that most of the qpf may be south of them. Although, they do get some qpf...but most of it may fall near secondary low.

BTW, GFS for next week is still mild, but now develops the low over wrn/ctrl mass. Maybe a brief start of snow or wintry mix before flip to rain??

[CoastalWx]

Oh boy. GFS chucked the mother load on 12/7.

[CoastalWx]

Dear Lord...lol.

[CoastalWx]

It retrogrades the PV and phases it in the Midwest giving a monster bomb.

[Tropopause_Fold]

It looks like the setup where the classic areas along the east slopes of ORH...well just north of ORH through sw NH will probably hover near 31 or 32 for hours and then maybe inch to 33 or 34. I've been liking that area of sw NH, but the problem is that most of the qpf may be south of them. Although, they do get some qpf...but most of it may fall near secondary low.

BTW, GFS for next week is still mild, but now develops the low over wrn/ctrl mass. Maybe a brief start of snow or wintry mix before flip to rain??

wagons north?

GFS is like dec 1989 in the long range...with a blizzard on the 7th thrown in for good measure. LOL.

[Tropopause_Fold]

Dear Lord...lol.

yeah just saw that. ridiculous. how sweet would that be??

[Baroclinic Zone]

Oh boy. GFS chucked the mother load on 12/7.

[CoastalWx]

Wait until NCEP catches up. Classic.

[Tropopause_Fold]

gfs

next few images, bob.

[Baroclinic Zone]

It retrogrades the PV and phases it in the Midwest giving a monster bomb.

HM did say that anything could happen given this pattern.

[Baroclinic Zone]

next few images, bob.

I know. That's the setup.