3/19/06 NOW: West Central TX

[Graham Butler]

Since no one is talking about it and we are west of Ozona on I10; I thought I would go ahead and start a NOW thread on these supercells which are taking shape. We are about 10 miles east of the southern storm on I10. This storm has a hard updraft, a visible flanking line, and is south of the WF for sure!! Our current obs on the chase vehicle are 72/63. Its going to be a tough chase for awhile with limited road options and these west Texas canyons.

Graham Butler

 

[Matthew E. Engelbrecht]

Reference the storm in Crockett County, TX - it appears that the storm has interacted with an outflow boundary that is laying E-W roughly along US Highway 190 and has become a supercell. I wouldn't be surprised to see a tornado or two from this. If the storm can continue to turn right and ride along this boundary, it may intermittently continue producing tornadoes. However, if it continues NE and crosses the boundary, it will likely lose its' supercell characteristics as it encounters increasing amounts of low-level stability and the main threat will shift to large hail.

 

[Brett Adair]

Tornado warned now. There is an OFB the storm is running on that extends to just south of San Angelo. Looking at SRV data, there is a high likelyhood that this thing will drop a twister within the next 30 minutes on the boundary.

Radar is now indicating somewhat of a double hook structure and Level II data indicates a 117kt gate to gate shear lock.

 

[Matthew E. Engelbrecht]

Additional convection is initiating across the US-Mexico border near Del Rio at this time. Storms are almost immediately taking on supercell characteristcs on Z/V data. RUC analysis indicates that these storms are moving into an area of decreased 0-6 km SRH as a result of weak H85 winds - but this may not be the case according to area WSR-88D VWP. These storms are forming along the effective warm front and are moving into mid-60s dew points. I would expect the far southern storm to persist the longest, with the storms to the northwest of it struggling more.

 

[David Douglas]

The cell north of Ozona now has 5 TVS signatures listed... wow!

 

[Scott Olson]

SWU reports 'hen egg size hail'. Even an appearance of 77.5dbz echo from at least 15kft.

 

[rdale]

Large area of 65+dbZ hanging over and coming down on both sides?

http://skywatch.org/ksjt_20060319_2345.png

MEHS reporting around 2.5" for a while now - peaked over 4" earlier!

http://skywatch.org/ksjt_mehs.png

 

[Matthew E. Engelbrecht]

The storm appears to be strugging to maintain supercellular organization at this time. It is on the far north end of the surface warm front, so this may be at the far north extent of where supercell structures can be supported....

Giant hail appears likely as the storm nears and crosses US Highway 277 between Eldorado and Christoval.

 

[Graham Butler]

We are now dropping south on 277 to decide what to do next. On 190 we encountered consistant 2" hail with larger pieces likely spiking in the 2.5" range if not larger. As it was riding the boundary we saw a few needle funnels but no touchdowns. If this thing put one down, and it very well could have, it would have been wrapped up in rain.

-Graham Butler

 

[HAltschule]

Interestingly, the cell has imploded and looks to be falling apart. So much for that one.

 

[David Douglas]

Nice cell now in Bandera County, moving in to Kerr & Kendall County.

 

[Matthew E. Engelbrecht]

Shortwave evident on WV imagery has dove south over California and is now rounding the base of the large-scale trough over the Baja of California. This will likely initiate another substantial round of thunderstorms over south Texas in the next 5-7 hours...and increase rain and snowfall rates further north over the plains soon thereafter.

 

[Matthew E. Engelbrecht]

A supercell, probably high precipitation, is now approaching Austin, TX. Thermodynamic and kinematic parameters favor maintenance of this storm at least until it reaches I-35 as it rides along the surface warm front. Thereafter the dynamics weaken further downstream. If the LLJ increases in the next hour, this storm may make it a ways past I-35. Some cell ingestion noted on forward flank of the storm in the past hour.

...but for now, this storm appears to be a tornado threat to the Austin metropolitan area, possibly just south.

 

[T. W. Miller]

Another large supercell approaching Uvalde, TX ..now with tornado warning. Interesting that the supercell threatening toward Austin area achieved first tornado warning in similar region (north-south line) as 2nd storm. Uvalde cell appears will threaten San Antonio area soon.

 

[Bill Tabor]

Chase partner David Douglas in Dripping Springs Tx (south of Austin) is now battening down the hatches and going into hiding as the inbound TVS / tornado warning has Dripping Springs directly in it's sites next. This storm also has a history of producing baseball hail. Let's hope that David fares well.