The exceptions: Northeast and CA.
(The cold will come, at first in quick shots, then likely more consistent mid-late Dec.)

Question is, how far south into Florida does the #cold air penetrate? Euro model is the most aggressive with 30s into the #Tampa Bay Area and 40s for parts of South FL.
Other models not as far south.
Stay tuned.

(Euro data not available). All other models were somewhere in between. Worth noting, on intensity, Andy Hazelton HAFS models kicked booty and were often the best/ close to the best in this arena.
Thanks to Brian McNoldy U Miami for his analysis.
(Error numbers are approximate)

On Melissa GFS 5-day error was 4X that of Google Deep Mind AI, our best model.
For the season Google AI track was 2X better than GFS.
@NHC_Atlantic knocked it out of the park again, using all the available info, and winning the season. It’s why we trust NHC, these folks are the best 2/

How exactly this will play out and what impacts it may have on our real weather on the ground varies from model to model. This is meant to educate on what the process can look like.
For more info, check out my post yesterday which describes in layman terms how these work and what impacts may follow

Notice on top how the frigid Polar Vortex (L) is large and in charge. On the bottom panel - 2 weeks later - warm high pressure expands & impinges on and displaces the cold vortex circulation.
This can “unleash” frigid Arctic air trapped in the once strong vortex circulation... 2/

Hi Annie... I'll need to look into that. But methane as a whole only causes 30% of global warming. Globablly Ag only makes up 25% or less of carbon emissions. Just at a quick glance. I need to dig deeper.

No it is 50 mb

Different every time but prob cold

So how far into the Deep South does that cold air reach? To the Gulf Coast? Will Florida get in on some of the action, or will it remain north? The devil is in the details, which won’t become entirely clear for a little while.
Stay tuned!!

So the result is that this Sudden Stratospheric Warming - Polar Vortex disruption - along with many other cold climate signals look like they will pile on each other/ constructively interfere to create a good chance for one the Coldest December in years across the US! (but its not set in stone)… 5/

On its own, it can mean Arctic outbreaks in the mid-latitudes and other extreme weather.
But this time it coincides with a multitude of very cold signals in the natural oscillations which dictate climate patterns. (You may have heard of La Niña, the MJO, the AO, etc…) 4/