TORNADO WARNING TXC463-121245- /O.NEW.KEWX.TO.W.0003.110512T1206Z-110512T1245Z/ BULLETIN - EAS ACTIVATION REQUESTED TORNADO WARNING NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX 706 AM CDT THU MAY 12 2011 THE NATIONAL WEATHER SERVICE IN AUSTIN SAN ANTONIO HAS ISSUED A * TORNADO WARNING FOR... CENTRAL UVALDE COUNTY... * UNTIL 745 AM CDT. * AT 704 AM CDT...NWS METEOROLOGISTS HAVE DETECTED A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO NEAR CLINE...OR ABOUT 19 MILES EAST OF BRACKETTVILLE...MOVING EAST AT 30 MPH. * SOME LOCATIONS IN THE WARNING INCLUDE LAGUNA AND UVALDE. PRECAUTIONARY/PREPAREDNESS ACTIONS... IF YOU ARE IN A MOBILE HOME OR VEHICLE...GET OUT AND GO TO A STURDY SHELTER. IF NO SHELTER IS AVAILABLE...LIE FLAT IN THE NEAREST DITCH OR OTHER LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS. A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1000 AM CDT THURSDAY MORNING FOR SOUTH CENTRAL TEXAS.
Thursday, May 12, 2011
|Today's overall risk of severe weather|
Weak to Moderate instability will once again develop as high temperatures and high dewpoints combine for a hot, sticky day. This system will impact the Eastern Plains into the Appalachians, and the Appalachians southward along the Coast.
A big factor is how these storms are becoming more unclear. Shearing fields are becoming more modest than predicted, which would lower the already low tornado threat and some wind threat.
Convective outflow from earlier storms has stabilized the atmosphere in the South/East Texas region into the Mid Missouri Valley.
However, should a cluster of storms develop, strong mixed layer CAPE would support a threat for hail and wind.
In the Plains northeast to the MS valley, convective development is also hazy. Early clouds ongoing in these areas are stopping instability from developing. It can be expected these clouds should remain at least an hour more in the Plains.
Although surface wind will be weakening, marginal shearing will give some potential to supercellular development. Should expected steep lapse rates and pockets of some mixed layer CAPE come through, an impulse will provide the forcing for storm development. This would contain large hail and damaging winds. However, in my own view, I would tone down this forecast, as current infrared imagery indicates some sort of disturbance and cloud cover in the Plains.
In the Lower Great Lakes and Upper Ohio Valley, a moist boundary layer may become fairly unstable from daytime heating. Shearing will be weak, as will deep layer flow. However, a shortwave will provide forcing for potentially substantial storms to fire up in this area. The expected initiation times would occur 7am- 4pm or 8am- 10pm CDT.
|Risk for hail|
|Today's risk for tornadoes|
|Today's risk for damaging winds|