November Medium/Long Range Discussion

[Eskimo Joe]

 

 

[Stormchaserchuck1]

If this verifies, we could be looking at our first winter storm threat around or after Thanksgiving. Maybe more 40N-north. 

18z GFS ensemble mean at 384hr also had a pretty strong -EPO developing.

Basically, the NAO is negative for the next 15 days, then the block retrogrades to NE Canada, just when the Pacific changes to more -epo/+pna around Nov 24-25 and after. That actually creates a window for a trough to track across the US, under the -NAO ridge in NE Canada, giving us a chance for a storm to hit colder air after Thanksgiving. The H5 in the map below is good, but we probably need a few days to flush out the old slightly warmer pattern. Still a long way to go, but it's looking good for at least below average temps beyond Day-15, based on current long range models.  That cross polar ridge, with a GOA trough and 50/50 trough (although both are weak) is what you want to see -- especially good ridging over Alaska. It's a winterystorm pattern, although early in the year. 

[WxUSAF]

Great thread from @griteater on the weakening early season Strat vortex and connections to a -NAO in December-ish.  His two closest analogs are December 1981 and early January 1982 and December 2000.  December-January 81/82 was a very cold and snowy period for our area, especially January. December 2000 was quite cold, but fairly dry without much snow.  

 

 

[mitchnick]

18 minutes ago, WxUSAF said:

Great thread from @griteater on the weakening early season Strat vortex and connections to a -NAO in December-ish.  His two closest analogs are December 1981 and early January 1982 and December 2000.  December-January 81/82 was a very cold and snowy period for our area, especially January. December 2000 was quite cold, but fairly dry without much snow.  

 

 

I'm not confident on the MJO getting thru phases 7-8-1-2 as he mentions at the end of his post. Failure to get thu them would be a negative for us.

https://www.stormsurf.com/page2/links/mjo_phase.html

[WxUSAF]

Just now, mitchnick said:

I'm not confident on the MJO getting thru phases 7-8-1-2 as he mentions at the end of his post. Failure to get thu them would be a negative for us.

https://www.stormsurf.com/page2/links/mjo_phase.html

Fair point. The IOD and Nina are going to favor phases 5-6.

[frd]

2 minutes ago, mitchnick said:

I'm not confident on the MJO getting thru phases 7-8-1-2 as he mentions at the end of his post. Failure to get thu them would be a negative for us.

https://www.stormsurf.com/page2/links/mjo_phase.html

Without help from the Pac you can have weeks and weeks of a - NAO and nothing will come from it in terms of snowfall for our area. As we know, depending on the pattern out West and in Canada some -NAO blocks don't work out for us,  and some do not even produce a pattern that leads to a cold enough airmass for snow, it is all dependent on the pattern upstream. 

I do believe the MJO slows, evens stalls for a bit, but we will get to the favorable phases in December and January.   

[Weather Will]

Latest EPS extended MJO.  I read 7 is good in December.

[frd]

Lastest AO update  11/09/25  - an increased negative forecast without a return to going positive.  Looking good !