Iceresistance

18z GFS has 2 Major Winter Storms for Thanksgiving week.

Here's some things to know about the Winter Teleconnections as we head into Winter:

Positive AO: No Cold air present or primed to dive southward, warmer mid-latitudes as well.

Neutral AO: Cold Air North, Warmer to the south, no changes soon.

Negative AO: This is where the fun begins, the Warmer Air surges north, displacing the cold air & causing the Polar Jet to dive down into the Mid-Latitudes, bringing cold & snow with it.

Positive NAO (North Atlantic Oscillation): No features that could cause a block in the Jet Stream

Negative NAO: Features a blocking pattern, forcing the Jet Stream to dive down into the CONUS, bringing cold & snowy weather with it as well.

Positive PNA: Alaska Low & Ridging in the Western USA, any cold air that comes will be dislodged towards the East Coast

Neutral PNA: Weaker features, allows the cold to spill into the Central & Southern Plains

Negative PNA: Alaska Ridge & West Pacific Trough, any cold air will be shoved into the Western USA

First Freeze of the season, 30°F

Gone

TORNADO ON THE GROUND NE OF DUNCAN, OK!

Possible Couplet picking up on radar near Piedmont, Velocity is weak right now but it could ramp up since it's in a favorable environment for supercells.

6 minutes ago, Powerball said:

CAMs are showing mixed signals at best for DFW. Some of them are, in fact, duds.

So highly conditional setup here, but yeah, could be an active evening up in Central/Southern OK for sure.

EDIT: It's crazy that we're seeing a lot more severe weather threats/events this fall than we saw during the entirety of our actual severe weather season. 

I know! October was basically May except 5 months late!

It appears that there is a solid tornado threat for Oklahoma, especially the squall line tornado threat.

Very strong concern for my area (Central Oklahoma), SE Oklahoma, & Southern Oklahoma tonight. the SPC is calling for a higher chance of Tornadoes, up to Tennis Ball sized hail & 70 mph wind gusts.

It appears that the area of Highest Instability is along & east of I-35, along & south of I-40, along & west of US-75 or US-69, & along & north of US-70.

Well, that got interesting.

 

It's the Hurricane-force low ~500 Miles ENE of Bermuda, would it be crazy if it became a SS Hurricane?

Can someone please put out the Analogs for the back-to-back February Cold Waves? (1977 & 1978 for example)

I saw it on an another forum, but I've since lost it.

1 minute ago, 40/70 Benchmark said:

Not anytime soon.

More like, later this winter.

On 11/7/2021 at 7:12 PM, 40/70 Benchmark said:

-QBO helps by making the PV more susceptible to disregulation.

I can also confirm that this La Nina may have caused the PV to become more unstable & will dive down somewhere in the Northern Hemisphere.

The GFS is consistently showing an active winter pattern across the Central & Southern Plains, but the timing & storms strength is not in full agreement yet.

1 hour ago, ValpoVike said:

Or super overcooked right up to the final days....like what it did last spring in the 90"+ storm for the Front Range that turned out to be 2'-3'.

Yeah, I can confirm that this also happened when the GFS-Para existed as well.

9 minutes ago, ValpoVike said:

I'll believe there may be a storm if it still shows early next week, but the GFS is overboard usually...especially at this range.  I wouldn't take any of it verbatim.

 

Or if it develops consistency, like what it did in February 2021

The 12z GFS is getting me very strongly concerned for the Northern Plains, very high impact storm next weekend for the area with Blizzard conditions.

Parts of Western Nebraska will get up to 40 inches of snow with 9 to 12 Feet snowdrifts, the Dakotas & parts of Minnesota will have 2-3 Feet of snow with 5-8 Feet Snowdrifts.


 

Wanda has become Post-Tropical

I do want to mention that the CFS is having unusual consistency on possible winter weather in the Central/Southern Plains in early December.

The GFS model does have some consistency on this, but the timing & how cold it would get is not consistent.

9 minutes ago, StormchaserChuck! said:

Really nice +PNA Nov 15-18 on 6z GFS ensembles

What does that mean?

Ryan Maue has put this concerning tweet (twit), mostly for Texas though
 

Quote

"The threat for climate-induced extreme winter storms again in Texas this winter remains very high & the state remains increasingly vulnerable to wobbling polar vortex "deep freeze". Double dip La Niña."

I do believe that this Double Dip La Nina has caused the Polar Vortex to become unstable & spill somewhere in the Northern Hemisphere, but where is the question.

My Southern Plains Winter Forum: