The Storm Prediction Center has issued a Tornado Watch for central Texas this afternoon, with more likely to follow.
The tornado watch follows the convective outlook updated for this afternoon that calls for afternoon thunderstorms producing large hail with the potential for tornadoes.
Below is this afternoon’s convective outlook:
DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0153 PM CST MON NOV 10 2008 VALID 102000Z - 111200Z ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTN AND TONIGHT ACROSS CNTRL/ERN TX INTO PARTS OF THE S CNTRL HIGH PLAINS.... ...SOUTH CENTRAL STATES... IN THE WAKE OF THE NORTHERN BRANCH CLOSED LOW/TROUGH LIFTING NORTHEAST OF THE GREAT LAKES REGION...A LARGE COLD SURFACE RIDGE IS CONFINING SIGNIFICANT BOUNDARY LAYER MOISTENING/DESTABILIZATION MAINLY TO AREAS SOUTH OF THE RED RIVER. THUS...AS THE INITIAL STRONGER FORCING LIFTS NORTHEASTWARD LATE THIS AFTERNOON...IN THE EXIT REGION OF THE SOUTHWESTERLY MID/UPPER JET STREAK NOSING THROUGH THE SOUTHERN HIGH PLAINS...SEVERE POTENTIAL APPEARS LIMITED TO A RELATIVELY NARROW CORRIDOR ALONG A DRY LINE FROM PARTS OF NORTHWEST TEXAS INTO THE VICINITY OF A DEVELOPING SURFACE LOW OVER SOUTHEAST COLORADO. VERY LATE THIS AFTERNOON...INTO THE EVENING HOURS...IN RESPONSE TO A SHORT WAVE IMPULSE PIVOTING THROUGH THE BASE OF THE SOUTHERN BRANCH TROUGH...MODELS INDICATE THAT UPPER FLOW WILL BECOME INCREASINGLY DIFLUENT/DIVERGENT BETWEEN THE POLAR AND SUBTROPICAL JET AXES ACROSS CENTRAL TEXAS. THIS IS EXPECTED TO CONTRIBUTE TO INCREASING STORM DEVELOPMENT IN THE PRESENCE OF A MOISTENING LOW-LEVEL ENVIRONMENT WITH STRONG DEEP LAYER SHEAR SUPPORTIVE OF SUPERCELLS. ALTHOUGH LITTLE...IF ANY...MID-LEVEL COOLING MAY OCCUR...AS SURFACE DEW POINTS CLIMB THROUGH THE MID/UPPER 60S...BOUNDARY LAYER BASED CAPE MAY EXCEED 1000 J/KG...SUPPORTING STRONG UPDRAFTS CAPABLE OF PRODUCING LARGE HAIL. THE CORE OF THE SOUTHERLY LOW-LEVEL JET MAY DEVELOP NORTH OF THE UNSTABLE BOUNDARY LAYER...BUT LOW-LEVEL HODOGRAPHS NORTH THROUGH NORTHEAST OF THE HILL COUNTRY ARE SILL EXPECTED TO REMAIN SIZABLE...ENHANCING THE RISK FOR A COUPLE OF TORNADOES...AND LOCALLY DAMAGING WIND GUSTS. THEREAFTER...UPSCALE DEVELOPMENT INTO ONE OR MORE CONGEALING STORM CLUSTERS COULD MAINTAIN A RISK FOR DAMAGING WINDS AND HAIL INTO THE OVERNIGHT HOURS ACROSS PARTS OF EAST TEXAS INTO THE SABINE VALLEY ...WHILE NEW STORMS CONTINUE TO BUILD BACK TO THE WEST/SOUTHWEST ...TOWARD THE HILL COUNTRY.
Graphics representing the state of the Day 1 Convective Outlook (below left) and Active Warnings and Advisories (below right) at the time of this writing are below.
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You may wish to view our SPC Convective Outlook, HWwarnings, and HAMrad II product sections to stay informed of updates and developments.
The watch statement is below:
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 929
NWS STORM PREDICTION CENTER NORMAN OK
1225 PM CST MON NOV 10 2008
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
EXTREME SOUTHWEST OKLAHOMA
CENTRAL AND NORTHWEST TEXAS
EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 1225 PM UNTIL
700 PM CST.
TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 65 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES NORTHWEST OF WICHITA
FALLS TEXAS TO 40 MILES EAST SOUTHEAST OF JUNCTION TEXAS. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU9).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
DISCUSSION...THUNDERSTORMS ARE BEGINNING TO DEVELOP ACROSS CENTRAL
TX WHERE LOW-LEVEL MOISTENING AND SURFACE HEATING HAVE ERODED
CONVECTIVE INHIBITION...AND ADDITIONAL THUNDERSTORM DEVELOPMENT
APPEARS LIKELY DURING THE AFTERNOON ALONG THE WARM FRONT AND DRYLINE
NEAR THE RED RIVER IN NW TX. THOUGH MID LEVEL LAPSE RATES ARE NOT
PARTICULARLY STEEP AND CLOUDS HAVE LIMITED SURFACE HEATING THUS
FAR...GRADUAL MOISTENING AND CLOUD BREAKS W OF I-35 SHOULD ALLOW
SUFFICIENT DESTABILIZATION IN THE WARM SECTOR TO SUPPORT A SEVERE
STORM THREAT. MLCAPE VALUES OF 500-1500 J/KG AND STRONG
LOW-LEVEL/DEEP LAYER SHEAR WILL SUPPORT SUPERCELLS CAPABLE OF
PRODUCING A FEW TORNADOES...ALONG WITH AT LEAST ISOLATED LARGE HAIL
AND DAMAGING WINDS.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 25030.
...THOMPSON
cheers,
–patrick