December Medium/Long Range Discussion

[Chris78]

8 minutes ago, bncho said:

EPS says we're guaranteed to see measurable snow by 12/14... we shall see

You new here? 

[Steve25]

47 minutes ago, bncho said:

EPS says we're guaranteed to see measurable snow by 12/14... we shall see

90-100%. EPS smoking that good stuff today 

[CAPE]

These seem to be the 2 potential windows to watch via recent guidance- I still like the 10-11th, but the 6th is starting to look intriguing, with some potential for significant southern energy to eject northeastward from the SW, and a nice NA look. A lot of NS energy associated with the TPV lobe though as advertised, and we know how that goes with timing(phasing vs crushing).

 

 

 

 

 

 

 

[WxUSAF]

6” mean on the EPS for MBY!?! 

[Terpeast]

Fwiw both aifs ensembles and EPS have been cleaning up with verification scores at 500mb over CONUS. Other models aren’t even coming close. 

[poolz1]

1 hour ago, Terpeast said:

Fwiw both aifs ensembles and EPS have been cleaning up with verification scores at 500mb over CONUS. Other models aren’t even coming close. 

That's great to hear.  The difference at day 12-15 between the GEFS and EPS is pretty significant.  EPS is actually starting to get the look of its own weeklies forecast from a few weeks ago.  

[frd]

1 hour ago, Terpeast said:

Fwiw both aifs ensembles and EPS have been cleaning up with verification scores at 500mb over CONUS. Other models aren’t even coming close. 

What are your thoughts here ?  ( bolded part ) 

 

Tomer Burg   @burgwx

 

 

With the addition of the AIFS ensemble, I've also added plots comparing the EPS to the AIFS ensemble: https://polarwx.com/models/?model=comparison Some major differences emerge between them heading into the 2nd week of December, with the EPS colder than the AIFS in the eastern US:

Differences between the EPS & AIFS ensembles are largest over Alaska, with the EPS showing a deep cutoff low over AK reinforcing western US ridging. The AIFS ensemble does not explicitly show such a strong cutoff low, but also has larger spread in 500mb heights than the EPS.

 

 

 

 

[bncho]

GFS again with the Dec 6-7 event

[Ji]

15 minutes ago, frd said:

What are your thoughts here ?  ( bolded part ) 

 

Tomer Burg   @burgwx

 

 

With the addition of the AIFS ensemble, I've also added plots comparing the EPS to the AIFS ensemble: https://polarwx.com/models/?model=comparison Some major differences emerge between them heading into the 2nd week of December, with the EPS colder than the AIFS in the eastern US:

Differences between the EPS & AIFS ensembles are largest over Alaska, with the EPS showing a deep cutoff low over AK reinforcing western US ridging. The AIFS ensemble does not explicitly show such a strong cutoff low, but also has larger spread in 500mb heights than the EPS.

 

 

 

 

we got too many models. 

[frd]

46 minutes ago, Ji said:

we got too many models. 

So true ! 

[frd]

I would like some energy to arrive near mid December from our SW with cold air in place. Webb talks about a Nino like period possibly. 

 

Eric Webb  @webberweather

 

The ongoing MJO event in the West Pac has led to a *gigantic* build-up of westerly momentum (+U) in the tropical troposphere, w/ GLAAMa approaching +3 sigma; very El Niño-like. Eventually, some of this tropical +U will get injected into the mid-latitude storm track

 

 

Eric Webb @webberweather  46m

 

Very high +GLAAMa like this coupled with our La Nina base state is not exactly favorable for western troughing/-PNA & I expect this to remain generally the case thru late Dec or so, even tho the Euro weeklies are trying to argue otherwise.

 

[frd]

3 hours ago, CAPE said:

These seem to be the 2 potential windows to watch via recent guidance- I still like the 10-11th, but the 6th is starting to look intriguing, with some potential for significant southern energy to eject northeastward from the SW, and a nice NA look. A lot of NS energy associated with the TPV lobe though as advertised, and we know how that goes with timing(phasing vs crushing).

 

 

 

 

 

 

 

 

The 10 th does have real potential as you mentioned. Beyond that date things still look good for cold and snow potential.  

 

 

 

[bncho]

the end of the 18z euro was quite intriguing. our second threat is less than a week away already!

[CAPE]

49 minutes ago, frd said:

 

The 10 th does have real potential as you mentioned. Beyond that date things still look good for cold and snow potential.  

 

 

 

Nice to see the advertised Scandi ridge building into the NAO space continues to be persistent. A key feature if its real.

[Maestrobjwa]

4 hours ago, CAPE said:

These seem to be the 2 potential windows to watch via recent guidance- I still like the 10-11th, but the 6th is starting to look intriguing, with some potential for significant southern energy to eject northeastward from the SW, and a nice NA look. A lot of NS energy associated with the TPV lobe though as advertised, and we know how that goes with timing(phasing vs crushing).

 

 

 

 

 

 

 

The main reason for our nina struggles and why tracking is a pain. Chaos and it rarely goes right

[mitchnick]

40 minutes ago, bncho said:

the end of the 18z euro was quite intriguing. our second threat is less than a week away already!

I like the Eps better. Decently below freezing 850's and a swath of snow seemingly headed right for us.

[Weather Will]

I can't remember a December looking like this in such a long time....(WB latest weeklies)