December Medium/Long Range Discussion

[frd]

Good thread. 

Seems Ural high and especially the +EAMT may weaken the vortex. Seems mid December is the tipping point to see if, and how, this goes down.  Will it be enough, and will the vortex cooperate is the question. Tonight's Euro extended range will be very interesting, as Simon mentioned. 

 

 

[Eskimo Joe]

Ever so slightly optimistic about December. This time last year it was looking like lights out through January. Even seasonable conditions would be an improvement.

[frd]

This is an impressive drop , razor sharp if you will,  in the NAO. 

Have to see whether this holds in the days ahead. 

 

[Scraff]

7 minutes ago, Eskimo Joe said:

Ever so slightly optimistic about December. This time last year it was looking like lights out through January. Even seasonable conditions would be an improvement.

If we can get on the board in December (feeling enthused on that) with a possible SSW a few weeks from now? Sign me up ASAP!  

[psuhoffman]

14 hours ago, Rvarookie said:

You have quite bit of knowledge and always seem to be less weenie...How do you think this plays out for December?

Long range and especially seasonal is getting increasingly difficult because we are seeing some influencers configured in ways we’ve never seen before. The pacific sst is completely out of wack and the QBO has been behaving odd the last several years. Add in warning across the board and historical analogs are less useful. 
 

I am guarded but getting somewhat optimistic this ninoesque pattern is real. It’s pretty consistent across all guidance and getting closer everyday.  It’s being driven by IO convection and the retrograde of the AK vortex, both of which is well underway. 
 

But I think 2 factors determine if we end up with a December that produces and doesn’t just tease.  We’ve had some decent patterns in Dec recently that did us no good. The first 10 days I think might be a challenge due to the lack of any true cold air source.  The recent pattern has prevented any cold from building on our side of the pole. It will take a while to fix that and initially the ridge in Canada is a bit too far southeast to allow cold into the equation. That may change as the pna ridge retrogrades in response to the AK vortex retrogression. In the meantime we’re dealing with a crap airmass. It could work with a perfect track and timing but it could be frustrating if things don’t come together perfectly. 
 

The last factor is what happens after Dec 10. I think the MJO will give a big clue as we get closer. There are signs it may finally try to propagate through the Maritime Continent mid December. Those are the warm phases for us.  However...I’ve found that when you get a weak or fast wave through phases in conflict with the base state it doesn’t have as much impact. That’s why some weak MJO waves in cold phases didn’t save us the last few years and it’s why some warm phases didn’t kill us in colder years. As we get closer if we see signs the mjo is racing through the MC at a weak amplitude that is a very good sign this pattern may persist. If we start to see signs it wants to stall and amplify while near the MC that would hint this was just a very temporary blip and the base state to the winter pattern is likely to be hostile. It’s too soon to say right now. We will start to get hints soon. 
 

Happy Thanksgiving 

[Rvarookie]

1 hour ago, psuhoffman said:

Long range and especially seasonal is getting increasingly difficult because we are seeing some influencers configured in ways we’ve never seen before. The pacific sst is completely out of wack and the QBO has been behaving odd the last several years. Add in warning across the board and historical analogs are less useful. 
 

I am guarded but getting somewhat optimistic this ninoesque pattern is real. It’s pretty consistent across all guidance and getting closer everyday.  It’s being driven by IO convection and the retrograde of the AK vortex, both of which is well underway. 
 

But I think 2 factors determine if we end up with a December that produces and doesn’t just tease.  We’ve had some decent patterns in Dec recently that did us no good. The first 10 days I think might be a challenge due to the lack of any true cold air source.  The recent pattern has prevented any cold from building on our side of the pole. It will take a while to fix that and initially the ridge in Canada is a bit too far southeast to allow cold into the equation. That may change as the pna ridge retrogrades in response to the AK vortex retrogression. In the meantime we’re dealing with a crap airmass. It could work with a perfect track and timing but it could be frustrating if things don’t come together perfectly. 
 

The last factor is what happens after Dec 10. I think the MJO will give a big clue as we get closer. There are signs it may finally try to propagate through the Maritime Continent mid December. Those are the warm phases for us.  However...I’ve found that when you get a weak or fast wave through phases in conflict with the base state it doesn’t have as much impact. That’s why some weak MJO waves in cold phases didn’t save us the last few years and it’s why some warm phases didn’t kill us in colder years. As we get closer if we see signs the mjo is racing through the MC at a weak amplitude that is a very good sign this pattern may persist. If we start to see signs it wants to stall and amplify while near the MC that would hint this was just a very temporary blip and the base state to the winter pattern is likely to be hostile. It’s too soon to say right now. We will start to get hints soon. 
 

Happy Thanksgiving 

Thanks for sharing. Hope you and fam have good thanksgiving 

[CAPE]

Some close misses to the south/missed phases on the 12z GFS but man the opportunities are not lacking.

[BristowWx]

Close misses to south is just fine!  That’s quite a look.  Thanks for posting sir. 

[Chris78]

26 minutes ago, CAPE said:

Some close misses to the south/missed phases on the 12z GFS but man the opportunities are not lacking.

Yep. Nice storm track on the Canadian for next Friday/Saturday

 Temps just a few degrees to warm.

 

Although that storm track is too close to the coast for your BY liking.

[WxUSAF]

Canadian is a touch to slow so the marginal airmass we have after the cutter warms a bit. Need it a little faster. 
 

Either way, lots of chances probably and a complex pattern with a bunch of strong short waves. 

[Chris78]

5 minutes ago, WxUSAF said:

Canadian is a touch to slow so the marginal airmass we have after the cutter warms a bit. Need it a little faster. 
 

Either way, lots of chances probably and a complex pattern with a bunch of strong short waves. 

Your right.  last night's Euro was 24 hours quicker which made a difference. 

[poolz1]

CAPE's epo ridge going strong on the LR GEFS.....

Time to go fill up on carbs!

[BristowWx]

384 on GEFS looks almost epic at h5.  

[CAPE]

Something else interesting at the end of the 12z GFS run...been awhile since we have seen this. Something to monitor for down the road.

[CAPE]

4 minutes ago, BristowWx said:

384 on GEFS looks almost epic at h5.  

Very 2013-14.

[frd]

9 minutes ago, CAPE said:

Something else interesting at the end of the 12z GFS run...been awhile since we have seen this. Something to monitor for down the road.

Ventrice mentioned this yesterday. I believe there is a proven lag time to impacts here in North America. Buy gas futures !  

 

[dallen7908]

Based on my limited knowledge of this ...

Warmings have strong correlation with winter temperatures in Europe; not so much in the northeastern U.S..  We'll have to wait and see.  In any case, probably not much of a factor until mid-December

[StormchaserChuck!]

+PNA isn't going to verify like that, skew it warmer.. ridge north of Hawaii. 

[CAPE]

An interesting h5 look overall, but really lacking LL cold air. Would need a bowling ball to roll just to our south with dynamical cooling to get it done. Too far north this run.

[CAPE]

2 minutes ago, losetoa6 said:

I'm not buying the Euro racing Monday's closed low north through the blocking so fast . Just my .02

Somewhat different evolution this run. Not sure I would call that an actual block. Plenty of movement/volatility in the longwave pattern over the next week or so. The early week system ends up generally in the 50-50 position this run, but would need a better track(and not a weak wave) for significant frozen east of the mountains.

[CAPE]

Pretty nice h5 look here at the end of the EPS run, but still no legit cold in our source region as depicted. If the pattern progresses as the GEFS is suggesting, there would be some improvement in that regard towards day 15. One major caveat is the MJO, which is forecast to move into the "warmer" phases, although at low amplitude. That will have to be carefully monitored. Although I think there will be a few chances over the next 10 days or so, it appears the highlands are clearly in the best position for an early season snow event at our latitude. If the GEFS is correct in continuing to amplify the western US ridge( developing -EPO) then the lowlands will be in a better position for wintry weather by mid month and beyond.

[CAPE]

Enough of my input. I'm done here for awhile lol.Time to go eat and drink. Y'all have fun.

[BristowWx]

Be nice to get a simple little overrunning event...couple inches..end of story....these deep plunging lows are like connecting your bat with a fast ball..great when it happens but happens rarely.  

[frd]

 

Update is in on the extended Euro. It does show a weakened strat vortex from mid December onward. 

 

[WinterWxLuvr]

I’m ok with the 18z gfs for late week. Bet that somewhere in the ensembles will be a couple of eye openers.

[Heisy]

5 minutes ago, WinterWxLuvr said:

I’m ok with the 18z gfs for late week. Bet that somewhere in the ensembles will be a couple of eye openers.

There’s not enough cold air to work with imo. Not saying it couldn’t work, but it’s a longshot

[WinterWxLuvr]

Just now, Wentzadelphia said:

There’s not enough cold air to work with imo. Not saying it couldn’t work, but it’s a longshot

As depicted, I agree.

[BristowWx]

Not often you see 528dm south of the FL line.  Late run GFS is quite nippy in the East.  It will feel like straight winter in the not so distant future.  Yeehaw

[Scarlet Pimpernel]

2 hours ago, Wentzadelphia said:

There’s not enough cold air to work with imo. Not saying it couldn’t work, but it’s a longshot

Yes, seems to be the problem around these parts all too often!  And this early in the season, especially.  But still nice to see potential out there instead of wall-to-wall Pac puke with no end.  Positive signs...for now, at least!

[BristowWx]

That is one cold op run.  Repeated cold on top of cold and then cold.