6/09/05 FCST: High Plains

Billy Griffin

Starting the FCTS thread for today.

500 winds will be increasing (slightly), although veering is an issue, and with sufficient daytime heating, CAPE is progged ~ 3500+ for the high plains. Max coming in later, along with residual outflow boundary may enhance convection potential.

Target = Wheeler/Shamrock ~ Amarillo, TX (I-40 corridor) on the southern-most end of the MDT risk area.

Initiation: 5pm

Anticipation: A few discrete cells with TOR potential early in cycle. SVR MCS in NW Kanas propogates SE across KS and into northern OK by AM. (this may help us for tomorrow! :wink: )
First of all, allow me to say that I think the better CAPE/SRH lies in Nebraska, but I think tornado chances are better further south along the dryline in terms of better isolation. Nebraska will have tornadoes, but I think the better storms will by far be south.

A hefty cap lies in place over the southern portions of the risk area this afternoon. If storms are able to fire, the cap will aid in better isolation and allow for good supercell development. West of about Lubbock, there is a bullseye of CAPE and SRH at 0z (4000J/kg + 350m^2/s^2). Also in that area is another bullsye of 350+ theta-E values. Behind this is a well defined dryline which should hopefully act to force the air upwards triggering the storm development. Temps in the low 90s with TDs near 70 will at least prevent massive T/TD spreads.

Further north into Nebraska, alot of the same parameters are in place... decent winds, good shear, CAPE, SRH, theta-E, but I concern myself with frontal development creating a mess too fast. As I mentioned above, Nebraska will have tornadoes, but I worry that the storms will move together too quickly allowing for a brief window for good storms before they join. As you go south, I think storms will be more isolated for longer periods of time.

My virtual target based on weather alone would be Lubbock, but the reality of my situation had I been able to chase would leave me further north than that, probably the Oklahoma Panhandle unless storms held off quite a while and allowed me a chance to at least make Amarillo.
There seem to be two pretty good target areas.

1)Northwest Kansas/Southwest Nebraska
2)Southwest Kansas/OK TX Panhandles

The cap looks too strong in region 2. Interestingly, NAM fires precip. RUC does not. Shear is incredible down there, and anything that can break the cap and sustain itself will be tornadic.

The warm front will be the main initiating mechanism in area 1. While 850 winds will be much weaker than area 2, they will be backed bigtime. Since the cap will be weaker there, I say game on for that area. Also, RUC forecasts 4-6000 CAPE! Probably overdone, but you get the point. Well, the DDC sounding has over 3000 CAPE.
Using KVII's SchoolNet, dew points across eastern TX Panhandle in the upper 60s to lower 70s while central and western Panhandle has dew points in the 30s and 40s (west of AMA just before noon CDT). Very nice, sharp dryline setting up. Outflow boundry moving across western Oklahoma and eastern TX Panhandle. Capes already on the order of 3k to 4k. This morning's AMA sounding had a Tc of 91. Initial target is Pampa (rather reluctantly given last two chases that started in Pampa were busts). Good luck to all those who go out today...be safe.

Brian Swiatowy
AKA Brian James
KVII-TV Amarillo, TX

EDIT: Okay...I'm going to let superstition get the best of me on this...with the dryline bulge starting to show up on the SchoolNet, I'm going to go east on I-40 to the rest stop to get data then decide what to do from there.