Jump to content

Met Winter 20-21: Pattern Drivers & Evolution


Recommended Posts

  • Replies 4.1k
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Popular Posts

While there's reasonable agreement on a -AO and -NAO persisting into early January, there is some uncertainty WRT whether or not the Pacific side offers any help or not. The EPS develops a +EPO into e

I'm starting to get a little more excited for early-mid December. It looks like the Pacific jet will retract significantly, which is the real reason for the retrograding Alaskan LP. Upper level diverg

Hey all!   I apologize for my absence as i'm currently in the "heat" of finishing up my undergrad, working on some side projects, and working with my advisor regarding, well grad school; tha

Posted Images

8 minutes ago, Dsnowx53 said:

I do think a lot of these concerns make sense, considering the high-latitude pattern still looks pretty poor, and the Pacific Jet will still have a good amount of background west to east momentum. Could make the aligning of the streams difficult, and I could see how this "mistiming" of streams with the flow splitting could lead to a Southeast US system as @Webberweatherwas alluding to. 

 

Regardless, though, these trends have certainly been nice to see on model guidance, and the EPS is not too terribly far off from the GEFS now, further evidencing that the MJO differences on the RMM plots between the GEFS and EPS is not necessarily making the GEFS solution erroneous. There's more going on here than what those plots dictate.

 

Despite the strong La Nina, I also never found an analog that I liked for this winter. A lot of the broader background signals looked pretty crappy as far as winter is concerned, but considering how we are already significantly deviating from the strong La Nina base state -- at the time of year when ENSO arguably has its strongest influences -- at the very least adds a lot more unpredictability to this winter than what has been implied. I'd much rather that than just locking in a torch for 3 months, that's for sure.

 

Deviation from the base state seems to be a common theme recently. What comes to mind is @earthlight tweet from late October highlighting one aspect of this (pattern observed in Sep/Oct). Expectations are low, but as always with seasonal predictions, there is a layer of unpredictability, perhaps this year more so than others.

 

Link to post
Share on other sites
21 minutes ago, Ace said:

 

Deviation from the base state seems to be a common theme recently. What comes to mind is @earthlight tweet from late October highlighting one aspect of this (pattern observed in Sep/Oct). Expectations are low, but as always with seasonal predictions, there is a layer of unpredictability, perhaps this year more so than others.

 

Looks like more cold air seepage this year FWEIW.

Link to post
Share on other sites
13 hours ago, Dsnowx53 said:

 

Hey all! I'd be lying if I could guarantee that I'll be posting in here as much as usual (I'm way busier now, I barely even ever tweet anything weather), but it's great to be back in here as we move into winter!

 

 

I do think a lot of these concerns make sense, considering the high-latitude pattern still looks pretty poor, and the Pacific Jet will still have a good amount of background west to east momentum. Could make the aligning of the streams difficult, and I could see how this "mistiming" of streams with the flow splitting could lead to a Southeast US system as @Webberweatherwas alluding to. 

 

Regardless, though, these trends have certainly been nice to see on model guidance, and the EPS is not too terribly far off from the GEFS now, further evidencing that the MJO differences on the RMM plots between the GEFS and EPS is not necessarily making the GEFS solution erroneous. There's more going on here than what those plots dictate.

 

Despite the strong La Nina, I also never found an analog that I liked for this winter. A lot of the broader background signals looked pretty crappy as far as winter is concerned, but considering how we are already significantly deviating from the strong La Nina base state -- at the time of year when ENSO arguably has its strongest influences -- at the very least adds a lot more unpredictability to this winter than what has been implied. I'd much rather that than just locking in a torch for 3 months, that's for sure.

Doug - It's great to hear from you and I think we can all agree that it's better to be tracking potential flies in the ointment of warm Winter guidance than knowing going in that we will have a Winter roast like 2011-12 with a raging east-based Nino. Look forward to tracking with you and everyone over the next few months and we will welcome any insight you might be able to share along the way. Cheers.

Link to post
Share on other sites
On 11/21/2020 at 7:38 AM, 33andrain said:

Doug - It's great to hear from you and I think we can all agree that it's better to be tracking potential flies in the ointment of warm Winter guidance than knowing going in that we will have a Winter roast like 2011-12 with a raging east-based Nino. Looks toward to tracking with you and everyone over the next few months and we will welcome any insight you might be able to share along the way. Cheers.

 

I expect the 1st tracking for western NY all the way to NNE in the 10 to 15.

 

20201121_081114.jpg.4203e32c22800ea83b0c883aa4d70695.jpg

 

And I think the GEFS makes the most sense in the east in the longer range with those heights pulled that far west into the Aleutians and a trough into Europe.

 

20201121_082431.jpg.527615028f2edb47c2454c3a2451883a.jpg

 

The trough " should be " in the east.

 

The EPS washes the trough out at 500, but it's SD is seeing where the main features are and does not respond in the east. 

I like the GEFS because that ridge axis is just west of the Rockies and the Euro agrees with it.

 

 

 

20201121_032408.jpg.0c905f18622879b61574fa4011178372.jpg

 

 

 

Link to post
Share on other sites
7 minutes ago, leo2000 said:

Very interesting indeed!

 

 

#ssw signs seems ahead in December....

 

 

Image

Yes. A disclaimer however... he says this every year and relies only on GFS guidance. Rarely does it materialize, and even if it does it doesn’t mean it favors us. 

Link to post
Share on other sites
On 11/20/2020 at 8:00 AM, PB GFI said:

It's nice to see the small EPS correct towards the cooler regime in the E US this morning.

Hopefully that trend can continue 

 

Notice if you stick the trough Fairbanks you drive the ridge through the GL.

Map compliments of 

@Webberweather

20201120_075448.jpg.8ab72d6426c53dfd653a4e1b1ed5028c.jpg

 

But when the negative can retrograde back towards the Aleutians, you center the ridge further W and open up the EC trough. 

 

The 6z GEFS really deepens the trough after this on the EC.

 

20201120_075416.jpg.24f62fa656c73c2934da6b06bff62837.jpg

 

I agree with Grace. Probably a N temp regime but not the plus 5 it has been showing. 

For December,  I can deal with average, don't need extreme cold regime to produce snowfall off the coast in the Mdtl/ NE.

Link to post
Share on other sites
1 hour ago, 33andrain said:

Yes. A disclaimer however... he says this every year and relies only on GFS guidance. Rarely does it materialize, and even if it does it doesn’t mean it favors us. 

But here is the catch it's not him saying it. It's coming from a Polar Vortex reseacher. He also doesn't only rely on GFS guidance. 

 

NOAA CFS modeling hinting at potential first-of-season stratospheric warming event by the third week of December.

 

Image

 

Link to post
Share on other sites
3 minutes ago, leo2000 said:

But here is the catch it's not him saying it. It's coming from a Polar Vortex reseacher. He also doesn't only rely on GFS guidance. 

 

NOAA CFS modeling hinting at potential first-of-season stratospheric warming event by the third week of December.

 

Image

 

The CFS is based off GFS parameters.

Link to post
Share on other sites
  • 33andrain changed the title to Met Winter 20-21: Pattern Drivers & Evolution
  • NJwxguy78 changed the title to Mid/Long Range:Met Winter 20-21: Pattern Drivers & Evolution

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...