5/5/06 FCST: TX

Tomorrow is shaping up to be another potential setup in this string of days. A shortwave ejecting out from the west will move into the region tomorrow and help kick off storms. Boundries will be plentiful again tomorrow as leftover junk from tonight does its magic, thus storms which fire and get involved with one of these will definately have the potential to produce severe weather, including the possibility of very large hail and isolated tornadoes.

ETA shows CAPE values near 3000J/kg in areas east of Lubbock. TDs are progged to be in the mid 60s throughout the area with a decent SE wind pushing that moisture in the area. 500mb winds aren't too terribly strong over the area tomorrow, but there is some difluence with the pattern which will help with lifting. The ETA is slow showing a tiny little vort max south of Lubbock at 0z, which has been noticed in a couple of the last runs. If this verifies, this could prove to be interesting as well.

If temps can hold in the mid 80s with mid 60s TDs, I'd say tornado chances will exist in this area. I think shear will be better overall than the past couple of days, so hopefully storms will have a better chance to spin.

I have a family event in Midland Saturday evening, so I'm making a last second chase day out of this in a rental vehicle; picking that up this evening and will be leaving DEN right around 5am for Lubbock (or a revised area tomorrow). Going to be a long haul out, but if I can keep within 250 miles of Midland for Saturday, I'll be happy in the end!
 
TARGET: MIDLAND, TX TIME OF DEPARTURE: 10 AM I did not chase the last two days as mid-level winds were very weak over the area. However, today is a different story with some energy coming in with the trough in the intermountain west. RUC is progging 40 knots over Midland at 500 MB. With easterly surface flow, there is ample deep layer shear for supercells. The only flies in the ointment I see are the stabilizing influence of last nights convection as well as the current activity, and the poor road network out in the Permian Basin. Also, the dryline will be held back due to pressure falls in the mountains. Low clouds cover the area, but I expect that to burn off later in the day. More energy comes out tomorrow, but I am unable to chase. Good luck. TM
 
Chase target:
Seagraves, TX (12 miles north of Seminole).

Timing:
Although elevated convection is already underway in the vicinity of the target area, expect this to eventually weaken and then surface based convection will initiate at 4 PM CDT.

Comments:
It looks like a great chasing day. Storms will be slow moving at around 10 mph to the east. Additionally, a great road network exists in this area. Between 5 PM and 8 PM, expect supercell storms with a full spectrum of severe weather, including tornadoes.

Discussion:
UA pattern indicates 130kt H3 streak rounding base of WRN CONUS trough and associated H7 SHWV surging though SRN NM. A 30kt LLJ has transported a tongue of 15C moisture into WRN TX, and elevated convection has already initiated near the nose of this jet. 12Z MAF sounding shows well defined EML on top of a 150mb deep moist layer having a mean mixing ratio of 13g/kg; while nearly 2000J/kg of CAPE is already in place. By late afternoon, MLCAPEs will increase to 4000J/kg.

Best lift should occur today along the northern edge of the SWRD sagging WV moisture plume, which should be aligned parallel and just S of I-20 by mid-afternoon. The shear parameters will be favorable for storm organization and rotating updrafts. Deep layer shear (SFC-6km) will approach 60kts with a 45kt H5 max over 15kt ERLY SFC flow. Local low-level hodographs will be impressive along and north of an outflow-enhanced SFC boundary oriented along US-180 as a 20kt LLJ lifts over backed SFC flow. Today, cloud base heights will be much lower then on the last few days in TX, which along with the large hodograph curves (SFC-3km SRHs to 300m^2/s^2) will favor tornadogenesis. With T/Td spreads of only 10F, LCL levels should locally be in the 600m range just N of the aforementioned SFC boundary.

- bill
 
I hope you're right, Bill, but we're pretty socked in with stratus and drizzle as we have been all morning. 57 over 57 won't get you much surface based CAPE. There is definitely some clearing further south, though, so those targeting locations near Midland may be in the best position, although most recent (12:40pm) obs showing the front may actually be moving a bit northward to just south of Tascosa (50 mi S LBB). Shear should indeed be better today than in previous days, so let the games begin.

Kevin
 
I hope you're right, Bill, but we're pretty socked in with stratus and drizzle as we have been all morning. 57 over 57 won't get you much surface based CAPE. There is definitely some clearing further south, though, so those targeting locations near Midland may be in the best position, although most recent (12:40pm) obs showing the front may actually be moving a bit northward to just south of Tascosa (50 mi S LBB). Shear should indeed be better today than in previous days, so let the games begin.

Kevin
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Where are you at? Looking at the MAF radar animation, I see a surface boundary along an Andrews to Big Spring line that is making slow northward progress. Satellite trends also indicate eroding ST. Once this happens, expect rapid destabilization between I-20 and US-180. A favorable scenario today would be for convection to fire along this boundary, with a backed SFC flow along and just north of it. Storm motion vectors are also parallel to the boundary, so cells would ride along it instead of forming and then crossing over to the cool/stable side and becoming elevated. An unfavorable scenario will be if convection fires further south first. It is a little unsettling to note the northern edge of the WV moisture streak (look at the water vapor animation), denoting the area of enhanced mid-level upward vertical motion, sliding southward. Notice how the CU is most enhanced here, just S of I-20. If storms fire to the south first, they will probably tend to become multicellular early in storm evolution; while robbing moisture and energy from any storms that fire along the WF.

- bill
 
Where are you at? ....
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Sitting in my office in Lubbock waiting for the work day to be over! Interesting how the winds have shifted a bit SE in areas like Lubbock that are still N of the front. Still some convergence down around Seminole, though not extremely tight. No matter, cu are starting to look more agitated in that area as per vis sat. Looks like convection has already fired over the Davis Mnts. area, hopefully the warm front will not be far behind.
 
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