Significant Warmth & Perhaps Tstm Potential Jan 12-13?

Wrn troughiness progged as cyclone drops swwd out of the Gulf of Alaska will allow subtropical jet to dip well into Mexico and then curve nnewd into SE TX and Arklatex. This will phase with the polar stream over the Upr Miss Vly and the result could be the genesis of an impressive storm system. Broad/strong southerly flow along and east of the Mississippi could see highs get well into the 60s as far north as the Ohio River region and perhaps 50s into the Southern Great Lakes. Wow that would be impressive. Meanwhile, DGEX LLJ looks to be 60-70 knots and with kissing jets looks like good ageo. circ and jet dynamics setting up. Similar solutions reflected in GFS/EMWCF. Will be interesting to see if it pans...if it does could see some decent storms across the mid-section of the country.

Didn't want to post this in the Target Area forum yet as it is still 5 periods out. Hopefully this consistency continues. Would be interesting to see thunder this far north, though I have my doubts. Better chances down towards Louisville and Indy.

...Alex Lamers...
I definately wouldn't be getting too excited yet. GFS has been all over the place with this, and has decided to break off the energy into the southern stream around 108 hours (as opposed to the older runs, which kept everything to the north, with no baroclinic zone development). Each run has shown this wave to be stronger. If anything, with 850mb temps in the 6-9C range across the Ohio Valley, and very weak instability compared to shear (not to mention the low sun angle, which won't help), I'm not really seeing anything significant,,, Yet, anyway :wink:
The 12Z Jan. 7th run of the GFS is giving the shortwave progged to reach Texas a more negative tilt. This gives more hope for a better moisture return and better shear.

If the necessary instability occurs across east Texas and Louisiana, I could see an intense squall line with imbedded tornadoes.

I'm getting ahead of's still several days out! I'm just wishing for a chase day in January....
Okay, now that the ETA is starting to pick things up, we can have a little more hope. ETA returns 55-60F Td's all the way to the lower Ohio Valley by H84, and produces pockets of 1000J/KG of CAPE (excellent for this time of year for that region). 12Z GFS between H84-H126 is VERY interesting, at least for now... It rapidly deepens a SFC low across the Rockies as it couples the southern stream and northern stream jet at 300MB. Strong WAA begins to take place at H102 along a 50-55KNT LLJ from SE TX to MO, bringing in 850mb temps of 9C. Over the next 18 hours from H102 to H120, the SFC low bombs out from ~990MB over KS, to ~970MB over Lake Superior. GFS shows vertical motion all along the strong front to be very intense. If anything, I would expect a strongly forced squall line with this type of setup, extending pretty far north fro SE TX to as far north as possibly IN.

When the ETA picks up the main WAA, it will be interesting to see how high it goes in regards to T and Td's. Already at H84, ETA has mid 60's T's working pretty far north, and with the WAA the GFS is forecasting, it wouldn't surprise me if the ETA went even high/further north (if the ETA developes that strong of a storm)...
Originally posted by Mike Hollingshead
What follows significant warmth?

That is going to suck.

They have been talking about another arctic front coming down here, like the one that visited us at Christmas. Supposed to be here in my area the weekend of the 15th/16th as told by local mets and some talk at the NWS.

What is inhibiting the severe with these fronts in SE Texas? I have been expecting some good booms and a possible spin up with these fronts and NOTHING. Mississippi got it last night. What is working against me? Please don't tell me it is my arch enemy, "that darn cap". :(

Are you referencing snow depths in relation to the potential warm up? I think by the time the GFS shows the warm up, most of the snow cover will be gone. If it was a quick warm up, then by all means snow depth would play a very important role.
I'm starting to wonder if this system will actually phase with the arctic low, as advertised by the 12Z GFS. Each run of the GFS seems to be taking that 500mb energy further south, and now there is even a hint of wave development along the arctic front. I guess it will all depend on where exactly the southern and northern 300mb jets couple, which at 108 hours is not exactly within the confidence zone...
It's still too far out to say anything with confidence. However I find it odd the GFS is not showing negative LIs across eastern Texas by 18z on the 12th. It's forecasting lower 60 Tds, 10C 850 dewpoints, and the intense verical velocites associated with the upper system cools the 850 and 700 temps. So warm midlevel temps inhibiting instablity shouldn't be a problem. Taking into account -14 to -16C 500 mb temps, I do believe when the ETA picks up on this system it will show at least some instability-negative LIs (assuming the GFS and ETA have the same handle on the system).
The ETA must have read Jim's post. On this morning's run (Jan 9) at least, this looks like a legitimate chase opportunity for the southern plains, from OKC to DFW or west of there, if the slowing trend continues. Model is showing a dryline structure moving into a narrow axis of modest instability, -6 LI and 1500 j/kg beneath about 35 knots of deep layer shear (eyeball estimate).

Spring is sending a postcard from whereever she's vacationing, at least for Oklahoma and Texas chasers.
That's right, Amos. The ETA either read my post or my mind! In any case it's forecasting the instability the GFS should have been a couple days ago.

As of the 00Z Monday ETA, the setup looks incredible for Oklahoma and north Texas, areas I-35 and east for tornadic supercells. However, the 00Z Monday run of the GFS is not slowing down the shortwave like the ETA. So we'll have to see how the two models differ over the next couple days.

Either way, I smell a big chase day brewing...
It seems like it would be very hard to keep things discrete with such strong low and mid level forcing, and nearly non existant CAP. Instability and shear look excellent, but also favor some pretty fast movers... I would suspect that some decent supercells would develop, and quickly organize into a pretty intense and fast moving squall line, based on the 00Z ETA. Still very impressive for January, none the less...
Hatched area on SWODY3

SPC's SWODY3 has a 25% line with a hatched area for significant severe. I have never seen this before-it must be something they just introduced, and it gives a certain ominous quality to the outlook...significant severe possibilities outlined 3 days out? :shock:

The first outbreak of 2005 may be looming...may everyone be in the basement when it hits.
Re: Hatched area on SWODY3

Originally posted by Andy Wehrle
SPC's SWODY3 has a 25% line with a hatched area for significant severe. I have never seen this before-it must be something they just introduced, and it gives a certain ominous quality to the outlook...significant severe possibilities outlined 3 days out? :shock:

The first outbreak of 2005 may be looming...may everyone be in the basement when it hits.

I think we can move discussion over to the Target Area forum now that the event appears more likely...