Winter 2025-26

[frd]

Snowcover and cold both become established in Canada by early December. This should help as the cold gradually pushes South with time.  

 

[Eskimo Joe]

20 minutes ago, GaWx said:

 The 6 coldest La Niña to neutral ENSO Decembers in the E US as a whole since 1974 have been 1983, 1985, 1989, 2000, 2005, and 2010:

 

 Here are the respective Dec MJOs:

1983: mainly inside COD or just outside/no strong

1985: almost all inside COD

 

1989: most of 8/1 just outside COD or inside it/no strong

 

2000:almost all just outside or inside COD

 

2005: all inside COD

 

2010: all just outside or in COD

 

 What do these 6 have in common regarding the MJO? No strong and most days just outside to inside COD. 
 
 Below are the extended progs that have the Dec 1-21 MJO: look how strong they are, especially GEFS but even the Euro is solid compared to the six cold Decembers posted. My concern is that the MJO amplitude will be too strong, based on history, to allow for a widespread intense cold dominated E US in Dec. Thus, I’m hoping the progs remain going into 8, but weaken. My hypothesis as to why strong MJO has had a tendency (though not always, of course) to not be as cold as weaker MJO is because the higher amp may tend to bring up too much warmth from the tropics, where the MJO is measured:

 
 

Any opinions?

 

[frd]

18 minutes ago, Eskimo Joe said:

 

I'm not even sure if it's wise to look at outcomes that far back.  

[Terpeast]

27 minutes ago, Eskimo Joe said:

 

No real opinion on past MJO results, but that little loop right in 7 before 8 tells me that there might be a brief period of split forcing - one in 7/8 and the other in 3/4. That split forcing in 3/4 should get suppressed quickly and we get fully into 8.

[Bob Chill]

2 hours ago, Eskimo Joe said:

I'd take a continuous series of light to moderate events that don't erode a block, vs one "big dog" storm that melts off in 4 days. Snow-on-snow is the best!

I'll be happy with one accum event before the holidays lol. Overall nothing shows a "snowy" pattern but all lr guidance is advertising "cold enough to snow" temperatures for several weeks in Dec.  We don't want mega cold anyways. Giant departures require giant high pressure and without looking back at data I'm pretty confident guessing that ice box December's are very dry here. 

From what I'm seeing we probably don't have much of a chance before Dec 10th but the next couple weeks after that will have enough cold over or around us to present a chance or 2. My yard requires a lot more work than yours this time of year so my imby lr forecast isn't very optimistic lol but I'll always root for the DMV

[Eskimo Joe]

4 minutes ago, Bob Chill said:

I'll be happy with one accum event before the holidays lol. Overall nothing shows a "snowy" pattern but all lr guidance is advertising "cold enough to snow" temperatures for several weeks in Dec.  We don't want mega cold anyways. Giant departures require giant high pressure and without looking back at data I'm pretty confident guessing that ice box December's are very dry here. 

From what I'm seeing we probably don't have much of a chance before Dec 10th but the next couple weeks after that will have enough cold over or around us to present a chance or 2. My yard requires a lot more work than yours this time of year so my imby lr forecast isn't very optimistic lol but I'll always root for the DMV

Well said Bob. Good luck to your backyard this winter.

[CAPE]

HH GFS.

Scandi ridge building into GL, +PNA, and an avocado trough digging south. Just a random op run ofc, but continuing to see the same idea across guidance as we head into the first week of Met winter.

[frd]

6 minutes ago, CAPE said:

HH GFS.

Scandi ridge building into GL, +PNA, and an avocado trough digging south. Just a random op run ofc, but continuing to see the same idea across guidance as we head into the first week of Met winter.

Looks encouraging, because some are worried about the SER and a rebounding PV in December.

If you simply look at an East Coast Nina in December you would expect the look that you have posted in the 18z GFS.   

[frd]

Eric Webb

 

@webberweather

 

 

The current global SSTa pattern is very favorable for the -EPO/+TNH pattern w/ the warmest water on the entire planet ~160E in the South Eq Pacific. The MJO is obviously giving it a huge boost here too.

 

 

 

 

 

 

 

 

Eric Webb

 

@webberweather

·

16m

 

 

I definitely underestimated how quickly this winter would dip into the ‘ol well of -EPO/+TNH we’ve seen so frequently the last 10-15 years. This pattern is only going to get stronger later in winter when the polar vortex intensifies& the warm pool starts zonally advecting east.

 

 

 

 

[WxUSAF]

We’ve generally had at least respectable winters in the recent +TNH years. 

[yoda]

6 minutes ago, ORH_wxman said:

Not sure we’d need any NAO ridging with that look. That’s pretty cold. 
 

That SE Canada and Atlantic look is very reminiscent of early to mid December 2007…the WPO is more negative than ‘07 though…that’s pure cross polar there  

 

 

I know this is from SNE... but would this be good for us in future days after?  Or is this a gradient pattern that sucks for us?

Today's 12z EPS at the very end btw

[CAPE]

11 minutes ago, yoda said:

I know this is from SNE... but would this be good for us in future days after?  Or is this a gradient pattern that sucks for us?

Today's 12z EPS at the very end btw

There would definitely be a lot of chaotic NS activity with that look, but should a wave take the southern route we could be in a good spot. Verbatim temps are marginal for us. Maybe a few days later would be better. Overall that same look a month later would be more favorable for the MA.

[CAPE]

^12z GEFS looks a bit colder for around the 7th. Realistically expectations should be low for snow at that juncture, outside of first flakes in the air kind of thing. Turning colder, yes.