Jump to content
  • Member Statistics

    17,502
    Total Members
    7,904
    Most Online
    Weathernoob335
    Newest Member
    Weathernoob335
    Joined

Winter 2019-20 Medium/Long Range Discussion


Hoosier
 Share

Recommended Posts

Obviously all the attention is on this weekends storm, but I must say, the long range is starting to look better and better per ensembles (& CFS, tho CFS has been hinting at this for a while). Bring on some more sustained winter, something we have not seen since November. Since then its been brief bouts, ie, yesterday at this time it was in the low 40s, now there is an inch of snow on the ground with temps in the low 20s and wind chills in the single digits, but tomorrow temps will rise to 40 again. Ensembles also look quite active. Hopefully fun times ahead for us all, so sticking with my call of more sustained winter late Jan into Feb.

  • Like 2
Link to comment
Share on other sites

The 00z EPS, in a big change in recent days, went to a broad west coast ridging and Alaska ridging out in day 10-15. PNA trended back to neutral on the teleconnection charts. So the hope there would be to not have an amplified western PNA ridge. If that sort of look verified as shown on the EPS it might be an active clipper/hybrid pattern versus the true dreaded CAD when the PNA ridging becomes more amplified and east based.

 

Also that sort of pattern would be good for the lake effect belts.

 

I've read some LR gurus wondering if EPS is rushing pattern change some, but it's done pretty well thus far this season.

 

Edit: As posted above, that look would more likely favor the east coast for larger synoptic systems but still no signs of a -NAO.

5cea44ca9211ed1855d2d4115740b5c1.jpg&key=cb6afe307d9239cb7841d1e0d4a2e8849f8d5336e2239ab83941d0b92e18c8c5b4a4f98537d1196629029a4a0f3f5ec5.jpg&key=869b19d1fba0e4864f4caa3dcb8c30892de0f900b8f681c210f7953fcee025fbfc2fea79b7d2d826fed0d547ad8e635c.jpg&key=c379813f61fc405e2f0d6672d335e4bc01bde5c2cd0cc0071ba16051a0664a61a7b4d2a514489fea92277b40c74dbc48.jpg&key=eda29ec3a9c91a23df5a2e5d1211bfa80c53c6564212a67bc88d70ef9f0992f9

 

Sent from my SM-G965U using Tapatalk

 

 

 

 

  • Like 2
  • Thanks 1
Link to comment
Share on other sites

2 minutes ago, RCNYILWX said:

The 00z EPS, in a big change in recent days, went to a broad west coast ridging and Alaska ridging out in day 10-15. PNA trended back to neutral on the teleconnection charts. So the hope there would be to not have an amplified western PNA ridge. If that sort of look verified as shown on the EPS it might be an active clipper/hybrid pattern versus the true dreaded CAD when the PNA ridging becomes more amplified and east based. I've read some LR gurus wondering if EPS is rushing pattern change some, but it's done pretty well thus far this season. 5cea44ca9211ed1855d2d4115740b5c1.jpgb4a4f98537d1196629029a4a0f3f5ec5.jpgfc2fea79b7d2d826fed0d547ad8e635c.jpga7b4d2a514489fea92277b40c74dbc48.jpg

Sent from my SM-G965U using Tapatalk
 

Hudson Bay Low

Link to comment
Share on other sites

3 hours ago, RCNYILWX said:

The 00z EPS, in a big change in recent days, went to a broad west coast ridging and Alaska ridging out in day 10-15. PNA trended back to neutral on the teleconnection charts. So the hope there would be to not have an amplified western PNA ridge. If that sort of look verified as shown on the EPS it might be an active clipper/hybrid pattern versus the true dreaded CAD when the PNA ridging becomes more amplified and east based.

 

Also that sort of pattern would be good for the lake effect belts.

 

I've read some LR gurus wondering if EPS is rushing pattern change some, but it's done pretty well thus far this season.

 

Edit: As posted above, that look would more likely favor the east coast for larger synoptic systems but still no signs of a -NAO.

5cea44ca9211ed1855d2d4115740b5c1.jpg&key=cb6afe307d9239cb7841d1e0d4a2e8849f8d5336e2239ab83941d0b92e18c8c5b4a4f98537d1196629029a4a0f3f5ec5.jpg&key=869b19d1fba0e4864f4caa3dcb8c30892de0f900b8f681c210f7953fcee025fbfc2fea79b7d2d826fed0d547ad8e635c.jpg&key=c379813f61fc405e2f0d6672d335e4bc01bde5c2cd0cc0071ba16051a0664a61a7b4d2a514489fea92277b40c74dbc48.jpg&key=eda29ec3a9c91a23df5a2e5d1211bfa80c53c6564212a67bc88d70ef9f0992f9

 

Sent from my SM-G965U using Tapatalk

 

 

 

 

I welcome a cold clippery pattern. Bring it. Thanks for the analysis, we have very few mets in this subforum. Please keep us updated in the coming days and weeks as well!

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

On 1/4/2020 at 9:09 AM, michsnowfreak said:

No doubt there will probably be fluke events, but as you said, pointless than expecting anything until it's 2 days or less out. The models seem extra up-and-down this year. Once the ridge starts moving further East, it seems as if the Great Lakes are in a bit of a battle zone, do you think that bodes well for a possible big winter storm?

I'm sorry for the horribly slow response to this...there could be a window around the 20th before the ridging develops on the West Coast for a larger storm somewhere in the Great Lakes or northern Ohio Valley.  After that, as RC suggested, once a PNA ridge develops on the West Coast the trough axis likely shifts far enough east that any synoptic storms are a little too suppressed for the Great Lakes.  However, with ridging into the EPO domain, it'd be a cold pattern that would likely feature clippers at least.

On 1/4/2020 at 1:37 PM, Snowstorms said:

Regardless of a pattern change, it sucks to lose December and the better part of January especially during the lowest sun angle too. It's hard to make up for that. 

Expectations for this winter were pretty high back in Fall. Part of that was due to low solar, descending QBO and weak El Nino. All of which would contribute towards blocking over the Arctic and Pacific. Although models show a pretty stout Aleutian ridge, there's still no sign of any pending snowstorms, even in the fantasy range. Let's not forget we lost December and half of January last year too. There have been comparisons being made between 2007-08 and the upcoming H5 pattern. Any insight on that? 

Yeah I'm a little frustrated about how winter has gone so far.  I think it's been a case of being just a little off...the QBO didn't go negative at 30mb until after January 1st (it should finally be negative this month), and the +IOD forcing was so strong that it suppressed Pacific forcing quite a bit...most notably in September and October, and again in December.  This combined with the QBO still being positive at 30mb to start window allowed the stratospheric PV to wind up quite a bit to start winter.  Pacific forcing favors Aleutian low development which is the way El Ninos tend to disrupt the stratospheric polar vortex.  I think if the QBO dropped a little quicker, or if we had more persistent Pacific forcing in fall/early winter that we'd have been in a much better spot right now.  We weren't and there's still time, but I agree it sucks to lose such a large chunk of the season.  In September-October I was worried about something like this happening, but in November leaned against it when Pacific forcing flared up for much of the month and we did disrupt the strat PV...I regretted it by mid-December when the +IOD base state re-emerged.  It seems nowadays that if there's a reason for a warm pattern that you're losing a big chunk of winter, even some of the good winters (13-14 a notable exception) have had prolonged mild spells the last decade.

I've seen comparisons to both 06-07 and 07-08 recently...both have interest because after relatively s**** first halves they improved markedly for the second half, with robust MJO passages into the western Pacific in January likely at least helping both turnarounds.  Ironically I think the QBO and low-frequency tropical signal favor an 06-07 evolution over an 07-08 one, though the composite for this month may end up looking more like January of 08 than January of 07. 

Here's the 06-07 evolution:

353626618_Jan07.png.99a765a8653486e6c71a73773bd267b7.png

1390946434_Feb07.png.a3ea05774f245e5c9bc6c54da32f894f.png

And 07-08

699987833_Jan08.png.42d769e5970c9350b866a0d448a47ff5.png

291468642_Feb08.png.9960c1ee93af803c87fcb9df5ae07515.png

Here's the January-March 2007 and 2008 MJO, followed by current EPS projections (which I think weaken it too quickly, it should get into phase 8):

1126745473_07MJO.gif.953858a2a642e015b7c9bf9961eec845.gif

1122259464_08MJO.gif.edd8d89ae9245a360d148ec5270c73d3.gif

249453246_EPSMJO.gif.3d3445f535bd4ff4b082692efa6285b1.gif

So, the January pattern this year looks closer to 08 with an Aleutian ridge, as does the MJO (especially if it gets farther around than the EPS has, which I think it will given how robust this wave is).  However, 07-08 had a much more decidedly La Nina low-frequency forcing pattern in the November-January, and we are a much closer QBO match to 06-07 this winter...here are the November-January velocity potential anomalies for 06-07, 07-08, and November-December this year (with the expectation that January will strengthen the uplift signal over the western Pacific somewhat):

2023878570_lowfreq07.png.2dc566c3cb05ef9a9945b447c0cbed5e.png

2025006249_lowfreq08.png.9691f5c2b28318d7278c62a523e8bee9.png

1219294069_lowfreq19.png.7eeb03458e9ceab9b7b3b01172a2863a.png

The lower frequency signal being more Nino like in 06-07 is probably why we had a much more El Nino like pattern during the second half of winter with a -NAO compared to 07-08.

If I had to look at the pattern now, I'd say an evolution closer to January-February 2008 is more likely than a 2007 evolution, that just looks closer to what we're seeing now.  However, the tropics being somewhat more Nino like this year and a descending QBO would normally argue for some blocking.  Given the robust MJO ongoing, low frequency forcing, and QBO, I think IF we perturb the stratospheric PV more substantially the second half of January that we probably see some sort of attempt at a -NAO, but if the PV remains strong (which it has so far this winter) we may end up paralleling 07-08 a little bit better and keeping a +NAO with more of a SE ridge.  My impression is we are going to see more -EPO help than either 06-07 or 07-08 had regardless, but there are arguments to be made either way regarding the Atlantic side which has big implications for the Midwest and East Coast...a -EPO but little Atlantic blocking is much better for this subforum than a -EPO and a -NAO. 

Either way, it seems like a transition back to a colder pattern is likely starting in about a week, with a robust MJO moving into the western Pacific being the catalyst for it.

  • Like 8
Link to comment
Share on other sites

On 1/6/2020 at 12:34 AM, cyclone77 said:

These positive tilted/southern stream dominant systems always underperform with cold sector precip.  Cold sector precip is narrow/fleeting where it occurs.  Without a northern stream component to phase with this will be a non-event except for maybe a 25 mile wide area that gets a quick 2-3" of slop.

:pepsi:

  • Like 1
  • Haha 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...