Severe Thunderstorm Warning 94, NWS Austin/San Antonio, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
900 PM CDT WED APR 28 2004

.UPDATED DISCUSSION...
AN UPPER LEVEL CLOSED LOW CENTERED OVER SOUTHERN MEXICO AND WESTERN
TEXAS...AS SEEN BY WV/IR SATELLITE LOOP...IS KICKING OUT TO THE
NORTHEAST...AS FORECASTED BY MAV MODEL GUIDANCE.

THE ONGOING THUNDERSTORM ACTIVITY OVER THE WESTERN COUNTIES IS A
RESULT OF THE SHORT WAVE TROF ROTATING AROUND THE CLOSED LOW.
CURRENT MOVEMENT IS EASTWARD ACROSS THE RIO GRANDE PLAINS REGION.
THIS ACTIVITY WILL MOVE ACROSS SOUTH CENTRAL TEXAS THROUGH THE NIGHT
AND BE OVER THE EASTERN COUNTIES BY MORNING.

THE STORM PREDICTION CENTER HAS ISSUED A WATCH FOR THE WESTERN
COUNTIES OF THE FORECAST AREA UNTIL 1AM CDT. STORMS ARE ANTICIPATED
TO BE MOSTLY MULTICELLS WITH HAIL AS THE MAIN THREAT.

WITH THE TROF MOVING EAST OF THE FORECAST WARNING AREA ON THURSDAY...
DECREASING CLOUDINESS IS ANTICIPATED AS YET ANOTHER UPPER LEVEL LOW
MOVES SOUTHWARD OUT OF THE GREAT DIVIDE INTO NEW MEXICO ON FRIDAY
NIGHT. THIS CLOSED LOW WILL BE THE FOCUS FOR THE NEXT ROUND OF
WEATHER INTO THE WEEKEND.

PREVIOUS DISCUSSION...
NEXT ROUND OF CONVECTION DEVELOPING OVER WEST TX/NE MEX THIS AFTN AS
A S/W TROF KICKS ENEWD OUT OF W TX TONIGHT.  CLOUDS LIMITING HEATING
OVER THE CWA THIS AFTN AND THEREFORE INSTABILITY...EXCEPT OVR VAL
VERDE COUNTY WHERE LAPS SHOWS INCREASING CAPES 1000+ WITH ONLY A WEAK
CAP. EXPECT CONVECTION TO THE WEST TO BECOME BETTER ORGANIZED...AND
AGREE WITH SPC REGARDING MARGINAL SVR STORMS OVR VV COUNTY THIS
EVENING. DEVELOPING MCS TO WEAKEN OVER THE CWA TONIGHT WITH LOW CHC
POPS EASTERN CWA THU MORNING.  DECREASING CLOUDS AND WARMER THURSDAY
AS S CENTRAL TX SHOULD BE UNDER SUBSIDENCE FROM A S/W RDG.  A CLOSED
LOW DIGGING TOWARD THE 4-CORNERS FRIDAY WILL INCREASE MID LEVEL
CLOUDS AND THE SLY SFC PRES GRADIENT...WITH A CHANCE OF DRZL/STREAMER
SHOWERS DURING THE DAY AS THE GULF MOISTURE SURGES NWD.  THE 4-
CORNERS LOW TO OPEN/KICK OUT AS A TROF FRIDAY NIGHT/SATURDAY...
DRIVING A CDFNT THRU S TX SATURDAY MORNING.  THERE WILL BE A GOOD CHC
OF SHRA/TSRA WITH THE FRONT IN THE MORNING...ENDING FROM THE N BY
THE AFTN AS THE UPR TROF SLIPS TO THE EAST.  BY SATURDAY NIGHT AND
SUNDAY DECREASING CLOUDS/COOLER UNDER THE NWLY FLOW...THEN AN UPR RDG
PREVAILS MON-WED WITH WARMING TEMPERATURES AND AN INCREASING SLY
PRES GRADIENT BY WEDNESDAY AS THE NEXT LOW DIGS INTO THE WEST.
WILL INCREASE CLOUDS AND ADD SOME LOW 10-20% POPS FOR WED/THU AS LLJ
DEVELOPS IN THE OVERNIGHT HOURS...AND COULD SOME PATCHY DRZL OR
STREAMER SHOWERS OVR MUCH OF THE ERN HALF OF THE CWA.

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.EWX WATCHES/WARNINGS/ADVISORIES...SEVERE THUNDERSTORM WATCH TIL
1AM CDT FOR THE WESTERN COUNTIES.

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