2/12/07 FCST: OK / TX

[Morgan Palmer]

I have been intrigued by what I'm seeing next Monday in north and northeast Texas, and eastern Oklahoma.

And I know, don't yell that it's so far out, but I'm wishing something up. So within the 7 day FCST parameter, this:

A good shortwave looks to come across from the southwest US with the forecast area being in the LF of a good jet streak by Monday week. Beginning Sunday night, the GFS develops a 40-60KT LLJ over the eastern part of Texas and SE OK.

Deep moisture appears, of course, to be limited, but as the low deepens in the Panhandle and western Oklahoma, and a dry line/front kicks eastward, we could see a good line of storms develop. The system is progressive, so I think it'll be a short lived event, but possibly quite potent!

Sweet dreams , and here's to an early end to SDS.
MP

 

[Billy Griffin]

Patience my friends, patience. j/k

Although I'm seriously doubtful that the atmosphere can recover from this arctic airmass serving up Winter to most of the U.S. right now. Gotta like the active weather pattern right now though. Just need to let nature take care of the rest. Model data I've looked at just doesn't serve up any reasonable moisture, and temperatures still at or just below average for the period. Daylight hours are still very limited as well.

I know... the older I get, the longer winter seems to get as well, but rest assured, spring will arrive again!

 

[Mike Umscheid]

"cold core" setup in southeastern TX PH??

In compact, strongly developing systems like this one on Monday 2/12, pay heed to potential "cold core"

NAM suggests a sliver of 50-52 dewpoints nosing northwest to the surface low near CDS... a compact surface low with significant frontogenesis in vicinity of mid level PV anomaly. A "hot" (for Feb standards) synoptic dry intrusion/downslope plume will spread east into the PH providing insolation. It looks like the timing may be pretty good (around 21z) when the surface cyclone (per vertical vorticity fields) really develops. The kinematic signals appear to be there for an interesting isolated tornado right in that near surface vertical vorticity maxima at the nose of 0-3km AGL near-dry adiabatic lapse rate plume, where significant deep tropospheric lift will be occurring. It'll be a small area of focus, much like 26 Oct 2006 event, although the mid level PV anomaly is not as "anomalous" as that event. Total SBCAPE in this area could go from ~100 J/kg to 700 to 800 in a matter of a couple hours given insolation and magnitude of deep layer potential instability... ...or I could be blowing smoke. I hope it snows here in Dodge

 

[Jeff Snyder]

Interestig potential for a possible psuedo-cold-core event across se TX panhandle and adjacent portions of extreme southwestern OK tomorow. The only backed sfc flow is largely north/northeast of the Hwy 287 corridor, which the latest NAM shows to be decked in with overcast cloudcover during the day. This leaves the best CAPE south/southwest of the Hwy287 corridor. Of course, this isn't too atypical, with dislocation between favorable shear and instability. In such cases, the "boundary" between these two favorable areas (or where favorable "parameters" overlap) is usually the place to be.

The good news is that the 00z NAM does show some decent 0-3km CAPE in the southeastern TX panhandle, and there may be a window for insolation and destabilization immediately ahead of the dryline. The surface features actually don't look too different (at least in relative positioning) from the 3-20-06 cold core event that produced a nice tornado in northwestern OK. In both cases, the "prime" area was/is immediately northeast of the sfc low, in an area of extremely backed surface winds and immediately ahead of the dryline/pac cold front. OF course, I think the 500mb temps on that day were several degrees cooler, as the 00z NAM is forecasting 500mb temps of 19-20C (with 20-22C temps a little farther south, per the graphics on Earl's page at least). Note that the CoD graphics (model progs and surface analyses/plots) haven't updated in more than 24 hours...

I'm taking a wait-and-see approach at this time. I just transferred my laptop hard drive to my brothers laptop, and I won't have a replacement until Weds. This means that I'll be without data assistance (well, I could bring his I suppose). In cold-core cases, however, positioning and targeting tends to be relatively easy, as you just anchor yourself down on the frontal boundary and wait for cells to interact or pass over that boundary. I'm interested in the Altus to Childress zone... Major props to Mike U for pointing this out!

EDIT: It's been correctly pointed out that this is not a true cold-core setup, since that term is typically used to refer to nearly vertically-stacked cyclones with a closed 500mb low. This is not what we have, so I should say "pseudo" cold-core, one with surface features similar to cold-core setups (e.g. sfc low with "bent-back" moisture advection to the northeast of the low with the primary "warm sector" well east and southeast of the "cold core" target area).