griteater

Posting the 18z GFS while we still have a winter storm on the models

GFS out to hr84. Should be another wintry run with wave 1 as the wave is hanging back again

Yeah we need wave 1 to be slower or wave 2 to be quicker to maximize wintry chances...neither idea is far-fetched. As far as the cold high goes, the CMC Ens at the surface has 32 deg with 20 deg dewpoint way down in south Georgia Friday morning - just shows the potential even if it's overdone

It's a bit wonky though because if we were to go toward this more wintry scenario of the initial wave hanging back, then coming out with good timing (a big IF), the Euro would have been the model that had that idea first. Bottom line, we are always going to question things until the flakes are flying and the ice is coating

Yeah Mr Euro has gone away from the initial wave scenario, and the GFS moved to it this run (and trending that way on the ensemble mean) The low budget models (JMA & NAVGEM) continue to like the more wintry early wave scenario as well

The cold front ushering in the colder air moves thru on Wednesday. One trend on the ensembles is for the next Pac wave to be not as amped up and a little more suppressed looking, at least initially, to where some precip could be thrown into the cold air by Friday - it's a possibility anyway. You can see here on the EPS trend loop how the Northeast cold vortex has trended to where it isn't moving out as quick....also, the trough in the southern plains isn't as amped (the height lines over the SE are trending more west to east instead of SW to NE - that keeps it colder). Of note, some of the GFS Ensemble members and the Canadian Ensemble mean show potential for light freezing rain deep into Georgia by Friday morning.

Here's a trend loop on the EPS for the wave over the 4-corners (this includes the 18z EPS run - the last image in the loop). Good trend

The 12z Euro Ens Mean was indeed colder, with the 32 degree here down into SC & GA

12z JMA is similar to the Euro 500mb evolution, but faster with the storm, and colder

Euro is very similar to yesterday's wintry 12z run at 500mb, but not as cold. At hr186, sfc low in NE gulf and cold high over New England. hr186-192 there is what looks to be frz rain from I-85 and NW in North Carolina

Euro is trying to go back to its wintry solution from 12z yesterday, leaving the early wave in Cali behind the cold trough before bringing it out

On the 12z GFS, the timing between the front bringing in the cold air and the follow up wave that kicks out and yields the storm was actually better this run. Problem is, the initial cold trough didn't press as much this run and it lifted out quickly, so it's warm with rain. Could be more chances coming down the line on the GFS run as it continues to be fairly cold out to hr249 12z UKMet at 144 isn't quite as quick to move out the initial cold trough as the GFS, though not a huge difference.

Canadian has what looks like a significant ice storm next Friday (ice to rain but heavy precip on the front end). Then ending as some light snow maybe - big, slow moving storm

It goes about it in a different way, but yeah, there’s potential here if we get a good cold dome to drop down. The GFS storm there is a follow on wave that drops into the trough

Likely won’t mean much in the end, but GFS took a step toward the Euro this run with a slower progression of the Pac wave thru California

To compliment hailstorm's note....Assuming we get the tall western ridge and cold shot as advertised, here's what I'm seeing with the main wave in question off the west coast. The GFS sucks it into the cold trough that is diving down. The Euro's cold trough misses the wave, so it has a slower trek west to east across the south. The UKMet is in between the 2. At hr144 (Day 6), the GFS has the wave in W Kentucky (sucked into the cold trough)...the UKMet has the wave in W Texas....the winning ticket is the Euro which has the wave in NW Old Mexico. Kind of fits with the old school bias of northern stream dominant with the GFS and slower/stronger southern stream with the Euro.

God I loathe these in and out cold snaps that are as quick as Barry Sanders, but I’ll take this 12z Euro hot dog run for now

^ Stronger +IOD look too, which makes sense (I think it will linger thru winter because of how strong it’s been )

Bob - after last winter, I almost joined you in the group that "doesn't do seasonals" but the affliction kicked in during October and I decided to write one. Thank you (and FRD) on the comments. Good luck to you all this winter. We'll chat with you down the road.

The Big 3 Ensembles for days 10-15 (Nov 23-28). Pretty good look.

Yeah, get that AK low to retrograde west a bit and we'll be OK...there are hints of it on the extended ensembles...and it makes sense to me that we'd have some retrograding there given that this will be after the time when the MJO has passed thru the Pacific (the MJO passing through the Pacific extends the Pac jet eastward - but it would retrograde thereafter). We'll see, the 10-30 day type forecasting is awfully tough

TORCON 7 winter incoming, I like it Big Frost!

^ Thanks and appreciate your notes...enjoyed reading them