griteater

https://twitter.com/griteater/status/1102657335598768128

February temperatures and 500mb to date

Live look at a wild U.S. Temperature Map

Surefire signs that winter has gone bad: 1. Severe weather talk in the eastern U.S. 2. Snow in Seattle and Portland

Chicago goes from a HIGH temperature of -11 on Wednesday to rain on Saturday night / Sunday. This winter proving to be an equal opportunity fail boat.

The cold plunge with the PV lobe dropping into the Great Lakes has held fine on the modeling, but the change has been that the subsequent flip to a poor Pacific pattern is moving in quicker now. We just haven’t been able to sustain an eastern trough this winter that is more common during positive ENSO

Don’t know if it is toast, but optimism should be low IMO.

The Pacific - North America pattern looks bad (warm) for the first 10 days of February. It would take a big block in the green circle there to overcome it

Yes I like the prospects for a storm chance in a window there after the PV moves E/NE out of the Great Lakes

You threw us off when you said “next week”, but yes, after the cold retreats following the PV drop into the Great Lakes, the pattern looks god-awful for wintry interests

Nice seeing the Euro with the Feb 2-3 storm, and FV3 was close. Not sure why anyone would be pessimistic about this time period in general. There is some decent pattern support for it

Canadian is more in the FV3/UKMet camp and is colder along the coast....on to the 12z's

For Sunday/Monday, the models are going about this storm in slightly different ways. The Euro is keying on the southern wave in the gulf and detaches it a bit from the northern stream as it moves out of the gulf then northeast into the eastern Carolinas - this evolution is on the warmer side. The FV3 and UKMet are keying on the northern stream wave that drops down into Bama, then east into the Carolinas, while moreso depositing the southern wave in the gulf - this evolution is a bit colder. The GFS is kind of a blend of the two camps. I would root for the FV3/UKMet solution, but with a stronger dive and "bottoming out" of the northern stream wave. There is a long line of storms going back in time that have trended west in that area off the SE coast. The early Jan storm last year kept trending west, for example....but getting the temps and storm to cooperate will be a bit of a challenge.

Or maybe in between your image 2 and 3 where the PV lobe over the Great Lakes moves into SE Canada and their is a window where a wave from the west could run into cold air that has yet to retreat

Quite honestly, the early December setup / 500mb configuration was excellent (southern slider w/ NE confluence and sfc high)....we (Greenville to Charlotte) need the early Dec configuration to go with the current cold air masses we have to our north/northwest. The 500mb configuration right now (Hudson Bay vortex) isn't the best, but can work.

GFS track for Monday Low is Bay of Campeche > Western Cuba > Bahamas

I'm struck by how the 500mb pattern manages to be super suppressive with the backside waves diving into the trough, yet not overly cold at the same time

18z FV3

Yeah the GFS looks pathetic for Sunday, but the 18z FV3 turns the corner with the wave in the gulf and has some phasing and produces some good late-blooming snow with the SE coastal low

I kind of doubt we get a good 50/50 low in this setup, but each of the ensembles (Euro/GFS/Canadian) hint at a couple of storm chances in the Sunday-Wed timeframe, even if they are low chance at this point.

This type of Hudson Bay / James Bay Vortex pattern isn't the best at producing highs over the Great Lakes and Northeast with a 50/50 low. However, when the trough is established across the conus, it can be a good mechanism for getting storms to track across the south with cold air in abundance lurking to the northwest. Here's an example storm that did work out in this type of pattern from New Years Day in 1962. Storm Totals were: Atlanta: 1.0 Gainesville, GA: 5.0 Charlotte: 6.0 Asheville: 6.9 Greensboro: 6.6 The wave/sfc low are off the British Columbia coast at the start of the loop...

Here's the 12z EPS Mean for Sunday/Monday. I think the move toward suppressing this thru the gulf is perfectly fine. I think the area of "greater concern" is the warming tendency. If the wave detaches from the northern stream, you lose some of the cold air that is necessary to keep the column cold enough east of the mtns and on the NW side of the low.

It’s another vigorous run of the Euro with the wave diving into the northern gulf. Looks like snows from Atlanta to Charlotte and north/northwest some. It looks a lot like the FV3 run but a bit west (warmer in E NC)

UKMet not digging the wave as much this run. It has a weak clipper type low moving into W TN at hr144.

Snow on the 00z FV3