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Pattern December to Remember

StormWatch said:
The 12z Euro from today actually looks good for later in the future this month - still currently thinking a colder pattern settling in within 2 - 2 and a half weeks. If you take a look upstream over the EPO (and part of the PNA) region, there's a deep trough that I beleive will transpire east of the Rockies between the 17th and 22nd (give or take) The waves from Russia would force the North Pacific blocking into the PNA region while some sections of the sinking air may become separated and go poleward. The blocking across the Central US I think would be a transitional warmth as the flow continues to propagate and that area of air I think would get forced over Greenland causing a possible strong -NAO signature.
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I don’t see a big ridge filling the middle of the country with a trough situated on both coasts. These two usually can’t coexist. That little block looks favorable. Cant wait to punt then unpunt a few more times over the next 30 days.
 
Lickwx said:
Weren’t they touting big cold for December anyhow ? So now that it’s in jeopardy no surprise they are finessing any possible way to show it will still get cold . Lol.
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I actually seem to remember them calling for a full on torch to start just after Thanksgiving and continued for much of December. What they put out today really isn’t much different from what Webb was talking about earlier, except their timing is sooner. I tend to lean more toward Webb’s thinking on the timing.
 
Jimmy Hypocracy said:
I don’t see a big ridge filling the middle of the country with a trough situated on both coasts. These two usually can’t coexist. That little block looks favorable. Cant wait to punt then unpunt a few more times over the next 30 days.
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Yep all this looks like is shortened wavelengths and then a boot of the EC trough and back to a EC ridge while the western trough ejects eastward, that blocking on top is weak
 
Jimmy Hypocracy said:
I don’t see a big ridge filling the middle of the country with a trough situated on both coasts. These two usually can’t coexist. That little block looks favorable. Cant wait to punt then unpunt a few more times over the next 30 days.
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Yeah this is a good point. While the short wavelengths are nice for the time being they aren’t sustainable for very long in the dead of winter. In the shoulder season (perhaps late Feb and into March) it’s a somewhat different story.
 
The system on the 8th if it got here earlier on Tuesday a.m I could see a lil onset mix till warm air kicks in. Maybe a lil in-situ CAD developing. Something to watch for us MTN peeps I guess.
 
Jimmy Hypocracy said:
I don’t see a big ridge filling the middle of the country with a trough situated on both coasts. These two usually can’t coexist. That little block looks favorable. Cant wait to punt then unpunt a few more times over the next 30 days.
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A ridge may not come into place, however if that strong frontal passage occurs, a strong high is likely to build in - causing higher heights behind the front. Since the higher heights would be associated with a transitioning high, the blocking will not be stationary. Those particular higher heights are within the main flow of transition over the Continental US.
 
NickyBGuarantee said:
Even though this is extended you have to expect we eventually make it to phase 8 and at what better time than early January we end up getting there
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We may never officially reach phase 8, even if we don’t that really doesn’t matter imo. Phase 7 is just as good if not even better in January (& best overall). Slow moving MJO events like this one have a tendency to produce a strong -NAO when we reach phase 7 & 8 in January. You can see a slight hint of that on the extended GEFS and the +SCAND showing up in the medium to long range is also one of the most classic circulation precursors to -NAO. I stand by what I’ve been posting the last few days, the flip to a potentially legit pattern is delayed probably until very late Dec or early January.
 
Webberweather53 said:
We may never officially reach phase 8, even if we don’t that really doesn’t matter imo. Phase 7 is just as good if not even better in January (& best overall). Slow moving MJO events like this one have a tendency to produce a strong -NAO when we reach phase 7 & 8 in January. You can see a slight hint of that on the extended GEFS and the +SCAND showing up in the medium to long range is also one of the most classic circulation precursors to -NAO. I stand by what I’ve been posting the last few days, the flip to a potentially legit pattern is delayed probably until very late Dec or early January.
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We’ll probably have a decent idea on when this pattern flip may occur later this coming week as our West Pac MJO event continues to amplify, but I think many are jumping the gun. Looks like rough sledding overall to me (no pun intended) until at least the Christmas holiday or so in the SE US. Winter probably gets going much earlier to our NW over the Midwest and Rockies
 
Webberweather53 said:
We’ll probably have a decent idea on when this pattern flip may occur later this coming week as our West Pac MJO event continues to amplify, but I think many are jumping the gun. Looks like rough sledding overall to me (no pun intended) until at least the Christmas holiday or so in the SE US. Winter probably gets going much earlier to our NW over the Midwest and Rockies
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Once upon a time we would have been stoked for a potential late Dec/early Jan flip, but now there’s trepidation due to being burned so many times. I’m trying to find some chill and remember this could be just fine timing.
 
Taking a look at the current 10mb layer (30km) You can see that the stratospheric PV is energetic, which is good because this shows that the upper PV is strong and probably still gaining momentum. Looking over the Bearing Sea/far Northern Pacific ocean there is clockwise rotation of winds in the upper stratosphere (blocking at 10mb over that region) This feature would help elongate the upper PV, however it wouldn't cause the PV to disrupt unless features come into place over the NAO region as well as over the Arctic Ocean such as further ascending upward motion of air. I don't think we'll see a complete main PV disruption anytime soon - however I do think we'll see mesoscale PVs coming down into the mid-latitudes at times as lower geopotential heights extend down southeastward at 10mb. The upper stratospheric blocking over the area mentioned looks to be persistent in the weeks to come, and I have suggested that a stationary high may get locked into place north of Europe over the Arctic ocean, if so, upward motion of warm air could eventually propagate into the upper stratosphere over portion of the Arctic Ocean, causing the PV to become further elongated. Also, the upper blocking over the Bearing Sea would help developing a trough over the EPO region (AK/Gulf of AK) in the lower stratosphere. At this time, I think it's best we may see extended periods of below normal temperatures later this month, but lower stratospheric blocking is what's going to cause frustration within the forecast. Challenging forecasting!

(Image: Current wind circulation at 10mb ~ 30km, I'll be keeping eyes on this!)
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