December Medium/Long Range Discussion

[dailylurker]

4 minutes ago, frd said:

Happens every year around the 22 nd of December like clockwork.

Not surprising really, although we have a stout - WPO there is too much Pac jet momentum. The Pac always rules as seen the past two weeks with a - AO and a - NAO and still nothing to show for it. I don't really care what folks say about climo as we had extreme cold air in Canada and a - AO and a - NAO, but in December you need a good PAC and a + PNA . We lost out because of the PNA.    

 

 

 

VA loved the pattern in early December. The more I learn about this stuff the more I believe it's all just random luck lol

[frd]

Just now, dailylurker said:

VA loved the pattern in early December. The more I learn about this stuff the more I believe it's all just random luck lol

Given the proper set up it could have been a SECS,  but alas the Pac did not allow it. At that time we did have a - AO and a -NAO. 

But the PNA was upgly.

 

[TSSN+]

Nam starting to show the little clipper for Friday. 
 

 

[NorthArlington101]

2 minutes ago, TSSN+ said:

Nam starting to show the little clipper for Friday. 
 

 

We’re in NAM range for a December event again? This has been awesome from a tracking perspective even if nobody north of Fredericksburg has too much to show for it, lol

[Eskimo Joe]

23 minutes ago, Bob Chill said:

A simple trough progression brings winter right back to the conus. Winter is lurking and waiting to pounce. Of course if the trough digs in the west, winter won't be in east for a little while lol but there is nothing depressing about that plot in the big picture. Move the swath of zonal into Canada and we in some trouble. Serious trouble lol

 

30 minutes ago, frd said:

Happens every year around the 22 nd of December like clockwork.

Not surprising really, although we have a stout - WPO there is too much Pac jet momentum. The Pac always rules as seen the past two weeks with a - AO and a - NAO and still nothing to show for it. I don't really care what folks say about climo as we had extreme cold air in Canada and a - AO and a - NAO, but in December you need a good PAC and a + PNA . We lost out because of the PNA.    

Thank you both for the explanation. I appreciate it!

[Terpeast]

My thoughts about the long term pattern and late month warm up:

 

[mitchnick]

1 hour ago, brooklynwx99 said:

AIFS ENS actually looks pretty nice. I feel like this is more likely given the tropical forcing but who knows

Very similar to the Cansips that keeps cold lurking to our north most of the winter. Here's a link to 2m temps starting in January.  Cansips actually likes January for temps over December, thoigh we've built up quite a deficit so far and will maintain most of it before the pattern breaks down.

https://www.tropicaltidbits.com/analysis/models/?model=cansips&region=us&pkg=T2ma&runtime=2025120100&fh=0

If you look at 5H anomalies, Cansips wants to have higher heights draped across most areas in the country south of 39-40N. It still gets at or a little BN temps in our area with the WxUSAF slow bleed idea. It's going to be low level, which will likely cause angst (zr/ip) threats, as 850 anomalies are not as favorable. 

All in all, we should still have decent chances in January if the Cansips is close to being right, and that map above says it may end up right imho.

[bncho]

37 minutes ago, frd said:

Given the proper set up it could have been a SECS,  but alas the Pac did not allow it. At that time we did have a - AO and a -NAO. 

But the PNA was upgly.

 

-PNA did not help the shortwave dig at all, so we just got weak sauce.

[mitchnick]

Latest Cfs2 weekly temp forecast. Not bad and looks familiar too.

https://www.tropicaltidbits.com/analysis/models/?model=cfs-avg&region=us&pkg=T2maMean&runtime=2025120900&fh=168

[yoda]

Fwiw, 12z ICON not interested in the Friday/Friday night idea... Saturday night is up in PA 

[Chris78]

3 minutes ago, mitchnick said:

Very similar to the Cansips that keeps cold lurking to our north most of the winter. Here's a link to 2m temps starting in January.  Cansips actually likes January for temps over December, thoigh we've built up quite a deficit so far and will maintain most of it before the pattern breaks down.

https://www.tropicaltidbits.com/analysis/models/?model=cansips&region=us&pkg=T2ma&runtime=2025120100&fh=0

If you look at 5H anomalies, Cansips wants to have higher heights draped across most areas in the country south of 39-40N. It still gets at or a little BN temps in our area with the WxUSAF slow bleed idea. It's going to be low level, which will likely cause angst (zr/ip) threats, as 850 anomalies are not as favorable. 

All in all, we should still have decent chances in January if the Cansips is close to being right, and that map above says it may end up right imho.

This.

In previous years Canada was torching so even when we did get a decent H5 pattern the airmass still wasn't great. 

Looks like good cold air in Canada to tap into.

Obviously all subject to change but it's not a close the blinds look at all.

And for your yard and my yard when it's been a really cold pattern I don't have any ground truth snow cover to speak of. It's all been south of our area. It's been that way for the last few years really.