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Pattern January 2020 - Operation Thaw Alaska

Saw HMs tweet about the AAM, that'll be helpful over the next month.

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Can already see those differences at hour 96, note on the GFS that secondary NS wave around ND/Canada which would end up strengthening and become a much stronger trough VS the euro 5372571A-C69D-43C2-B197-3DBBFBADBFF4.jpegB138DAF1-DB27-4E95-A3A3-A964CB19AB20.jpeg
 
Euro has light rain showers for parts of the tenn valley


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I’m no expert but this is a pretty drastic change from the euro from yesterday
 

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metwannabe said:
Don't care how this run ends but that is a huge improvement since 12z yesterday on the Euro... look at the pac ridge, 12z yesterday and then 12z today

View attachment 29290
Today
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Much better look....maybe less of a kicker? Not sure I like our friend the Lakes Low showing up instead of a cold High Pressure, but let's see what happens.
 
Rain Cold said:
Much better look....maybe less of a kicker? Not sure I like our friend the Lakes Low showing up instead of a cold High Pressure, but let's see what happens.
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Nothing happened lol but it was close to closing off... big changes from yesterday and I'm sure those changes aren't over.

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Rain Cold said:
I hope you're right about the end of January. I originally thought week 3 would start the transition to better, although that is likely going to prove to be a false start. I've been thinking the end of the month as well as the month of Feb would be when we'd have a few periods for durability of a favorable winter pattern. Nothing magical about that...just watching model trends, incorporating seasonality, and counting on earlier bouts of blocking as hints of what may lie ahead later in winter, along with an active STJ.

I actually think our odds of a significant winter event (or more than one) go above average later on.
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Yeah I'll be the first to admit, I screwed up on expecting the pattern to turn around Jan 5-15 & then subsequently stick, looks like it's definitely going to turn on time, but we'll go back to crap again until roughly late month thanks to this MJO wave really being a faster moving CCKW that attenuated over the Western Hemisphere.

The collective idea from the CFSv2 & EPS supports the idea for another fast-moving MJO pulse &/or slow moving CCKW returning to the West Pac by about Jan 15th or so.

chi200.cfs.eqtr (1).png

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It usually takes about 10-15 days for the pattern to turn favorable following West Pacific forcing in the heart of winter, hence my call for the pattern to turn yet again around roughly January 25-30. The few caveats we have here is that we'll already have a pretty strong ridge in the NE Pacific & this burst of subseasonal tropical forcing will be moving faster than a stereotypical MJO event because we're in a low frequency base state (NINO esque). This will significantly modify the amplitude and timing of the pattern change (perhaps even stronger -EPO & maybe a "faster" pattern change?, but over the last day or so, I've started to feel more comfortable w/ this idea in a general sense.

whmjo6.jfm.t850composite.web.png


In summary (once again) my thoughts timing wise on the pattern for about the next 4 weeks or so:

Dec 31-January 4 (ish): transient shots of cold & warm, (more warm than cold), moderately above normal temps expected

January 5-9: Favorable longwave pattern for one, maybe two chances of wintry weather in this period. Details remain unresolved atm, slight-moderately below normal temps seem probable if not likely.

January 10-24: Southeast ridge makes a triumphant return, mild-very mild with little-no chance of wintry weather. Well above normal temps seem likely even this juncture, severe storms seem like a decent bet at some point across the lower MS valley. Lots of cold air will be loaded into North America thanks to the strong NP high, seriously cold air will be knocking at the CONUS's doorstep, the northern Rockies & northern plains will probably be the first to contend with it.

January 25 thru early Feb: tropical forcing returns to the West-Central Pacific, pre-existing NP high becomes potentially even more amplified (& breaks into Alaska (finally?)). A more favorable pattern for wintry weather returns to the SE US, potentially persisting into at least early February.
 
Rain Cold said:
Much better look....maybe less of a kicker? Not sure I like our friend the Lakes Low showing up instead of a cold High Pressure, but let's see what happens.
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Meh, plenty of cold air and while it was a tad slower, it's still very progressive.... I think we either need it to close off or dig enough go negative tilt and pop a coastal late bloomer. Anyway a reprieve from the 70's for a few hours
 
for that weak wave to produce snow across parts of the SE, you want it slower and stronger initially so it could have a better shot at even going nuetral/negative tilt or just a strong enough trough for decent forcing for Convective snow, and GFS is doing exactly that, the energy you want to look at is north of Montana in Canada, that little cutoff, and the shorter term it’s been slowing down, and has became a little bit amped on the GFS, altho euro is not close, it took a step towards that 832711A8-ABAD-4EBE-A352-14C5EA385B9F.gif
 
Myfrotho704_ said:
for that weak wave to produce snow across parts of the SE, you want it slower and stronger initially so it could have a better shot at even going nuetral/negative tilt or just a strong enough trough for decent forcing for Convective snow, and GFS is doing exactly that, the energy you want to look at is north of Montana in Canada, that little cutoff, and the shorter term it’s been slowing down, and has became a little bit amped on the GFS, altho euro is not close, it took a step towards that View attachment 29294
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Hoping the eps shows that step in the right direction as well...
 
Myfrotho704_ said:
for that weak wave to produce snow across parts of the SE, you want it slower and stronger initially so it could have a better shot at even going nuetral/negative tilt or just a strong enough trough for decent forcing for Convective snow, and GFS is doing exactly that, the energy you want to look at is north of Montana in Canada, that little cutoff, and the shorter term it’s been slowing down, and has became a little bit amped on the GFS, altho euro is not close, it took a step towards that View attachment 29294
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Plus that feature is only about 90 hrs out so could have a better handle on that next 24-48 hrs
 
Fwiw & I know others (@Jon for ex) have mentioned this already but the CFSv2 has continued to progressively beat down the SE US ridge in later, more recent forecasts for January.

Most of this change is coming from the latter portions of the month (January 25th ish & beyond) when another, aforementioned bout of West Pac tropical forcing in mid-January tries to pump the NE Pac high into Alaska in late January so there's definitely a legitimate possibility it's wrong. Imo tho, it certainly looks like there's some light at the end of the tunnel following the return of the SER after January 9-10th.

cfs-avg_z500aMean_namer_4.png

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