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December and a Hint of January Pattern Discussion


Bob Chill

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Instead of muddying up the Nov obs/disco I figured it would be best to start a thread to discuss December. 

 

It's an unusually difficult call compared to previous years. For every good signal there is a bad one. Yesterday's trends backed off some encouraging signs but today is back in the game. 

 

6z gefs has a decent look d11-15. 12z op looks very encouraging with a displaced pv and ridging on both sides. The models have been teasing us with the atlantic starting to cooperate. 

 

Maps like this keep me on the chase for sure:

 

 

 

We'll have to see what the ensembles show later but they may continue to encourage. 

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I think maybe the best news is that nothing is showing up in the progs to indicate a persistent warm/snowless pattern for us, i.e., like a GOA low, SE ridge, etc...  I'd still favor a progressive pattern over a persistent cold/snowy pattern, but even a progressive pattern is a far improvement over what we've dealt with in December 2011 and 2012. 

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I think maybe the best news is that nothing is showing up in the progs to indicate a persistent warm/snowless pattern for us, i.e., like a GOA low, SE ridge, etc...  I'd still favor a progressive pattern over a persistent cold/snowy pattern, but even a progressive pattern is a far improvement over what we've dealt with in December 2011 and 2012. 

 

Most definitely.  Also, weenie question -- wouldnt the placement of that PV squash alot of our systems/clippers to our south?

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Most definitely.  Also, weenie question -- wouldnt the placement of that PV squash alot of our systems/clippers to our south?

 

Yes, verbatim it's an obvious problem. I'm more interested in the fact that it got displaced in the first place AND some ridging builds on both sides. General climo favors further north. 

 

I agree with WxUSAF on progressive. Even the -nao looks we've been teased with are transient in nature. In early December we need help in the temp department quite a bit. Having the pv on our side is a big part of getting big departures. Continental air still works when it's fresh I guess but obvious issues closer to the cities. 

 

When is the last time a pv wobbled around central canada in December? Maybe 2010? I can't remember. The last 2 years have scrambled my brain. 

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Yes, verbatim it's an obvious problem. I'm more interested in the fact that it got displaced in the first place AND some ridging builds on both sides. General climo favors further north. 

 

I agree with WxUSAF on progressive. Even the -nao looks we've been teased with are transient in nature. In early December we need help in the temp department quite a bit. Having the pv on our side is a big part of getting big departures. Continental air still works when it's fresh I guess but obvious issues closer to the cities. 

 

When is the last time a pv wobbled around central canada in December? Maybe 2010? I can't remember. The last 2 years have scrambled my brain. 

maybe this is the winter where the cold is on our side of the Pole for once and not Europe/Russia

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Nothing wrong with the 12z GEFS mean in the Day 11-15 timeframe.  -EPO, AO probably near neutral, some ridging out west, troughing in the east, signs of some southern stream action. 

 

ENS d8-16 precip maps show at least 10 members giving us over.75.

 

H5 also implies the pv on our side centered somewhere around hudson bay.

 

D11-15 temp departures put us solidly in -5 territory. The entire US east of the rockies is below normal. with the coldest running through ov-ma-ne. 

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I'll take my chances with looks like this anytime in DJF. The strength and placement of the pv in canada is highly suspect but there is growing consensus that it's going to live on our side of the planet in early Dec. Pac is on a long term friendly run and if we can get the atl so improve then I can't imagine escaping the 1st half of Dec without some chances and accum snow. 

 

 

 

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0z-6z gfs / gefs, 0z euro, and cpc superensembles d11+ continue to paint a clear picture of a cooler than normal first week of December. 

 

Northern stream appears to want to get active post TDay and the vort coming through the SW in a week needs to be watched. 

 

Still a lack of favorable blocking but the atlantic will likely be better as we move forward in time. Probably the biggest flag overall though. If the low in the sw gets organized there may be nothing to get in the way of a nw track but it's so far out there that analyzing each op run is kinda silly. 

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0z-6z gfs / gefs, 0z euro, and cpc superensembles d11+ continue to paint a clear picture of a cooler than normal first week of December. 

 

Northern stream appears to want to get active post TDay and the vort coming through the SW in a week needs to be watched. 

 

Still a lack of favorable blocking but the atlantic will likely be better as we move forward in time. Probably the biggest flag overall though. If the low in the sw gets organized there may be nothing to get in the way of a nw track but it's so far out there that analyzing each op run is kinda silly. 

December 3, 2002 showing up as 2nd best analog.  Ya'll know what happened 2 days later.  Just sayin'.   ;)

 

 

500hgt_comp_sup610.gif

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December 3, 2002 showing up as 2nd best analog.  Ya'll know what happened 2 days later.  Just sayin'.   ;)

 

 

 

 

lol- i know you know what I'm about to post but to keep expectations in line....

 

Dec 02 has been showing up on the analog list for 3-4 days now. While I agree that the ridging in the west and ak is similar, it was way different at high latitudes. Great -ao/-nao combo. Made it much easier for the storm to take a great track.

 

 

 

We're missing a couple of key ingredients this go around. Although, there are hints in the ens of the nao region to be more favorable in this timeframe so many possibilities are still on the table at this timeframe. 

 

Will it snow the first week of Dec this year? I'm leaning towards those odds. Will we have a snowstorm? Eh, with a lot of luck and timing...

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Very juicy coastal plain runner (Miller A?) Dec 2-5th on the 12z GFS.  Possibly suffering from convective feedback, but there is a nice 1035+ H in the Plains at the same time... will be very interesting time period to watch as has been mentioned above.  Also seems like there is something else showing up at the very end as well with another arctic air reload coming

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