Severe Thunderstorm Warning 12, NWS Austin/San Antonio, TX

SOUTH CENTRAL TEXAS FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
910 PM CST FRI MAR 21 2003

CURRENT RADAR TRENDS INDICATE GOOD TIMING OF THE INCOMING
PRECIPITATION. WILL UPDATE TO SLIGHTLY INCREASE POPS FOR THE WESTERN
HILL COUNTRY AND VAL VERDE COUNTY AND ADD A SLIGHT CHANCE OF
THUNDERSTORMS FOR THE REMAINDER OF THE HILL COUNTRY. BASED ON THE
LACK OF MID-CLOUD FORMATION EAST OF THE CONVECTION AREAS, WILL
ASSUME THE CONVECTION WILL NOT REACH THE HDO AND AUS AREAS UNTIL
AFTER 12Z SO WILL HOLD OF ADDING POPS THIS FAR EAST. FIRST WAVE OF
PRECIP IS NEAR SOLID OVER WEST CENTRAL TX, SO WILL ALSO RAISE
SATURDAY POPS BY 10 PERCENT. EXPECT THE TIMING TO COME CLOSE WITH
THE FIRST WAVE DEFLECTING JUST NORTH OF AUS/GTU AND ANOTHER ROUND
MOVING INTO CENTRAL SECTIONS JUST AFTER DAYBREAK. WILL NEED TO RAISE
MINS AND WINDS A BIT AS A SURFACE TROUGH EXTENDING NORTH OUT OF
MEXICO IS STEEPENING THE PRESSURE GRADIENT.

UPDATED NUMBERS...
AUS 046/063 045/075 048 -7200
DRT 052/070 050/080 054 55000
SAT 050/064/048/076 052 -6100

.EWX...NONE
18/3/DC

.AFTERNOON DISCUSSION........................................
AN UPPER LEVEL TROF MOVING ACROSS NEW MEXICO THIS AFTERNOON IS
SETTING OFF SCATTERED SHOWERS AND THUNDERSTORMS FROM NEW MEXICO
SOUTHWARD INTO FAR WEST TEXAS. THIS FEATURE WILL MOVE EASTWARD AND
TRAVERSE SOUTH CENTRAL TEXAS AND THE HILL COUNTRY ON SATURDAY.
SCATTERED SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE WESTERN
COUNTIES BEFORE SUNRISE SATURDAY MORNING.  THIS CONVECTION WILL
LIKELY BE ELEVATED. THE CONVECTION WILL INCREASE IN AREAL COVERAGE
SATURDAY AFTERNOON OVER THE EASTERN HALF OF THE CWFA AND WILL BECOME
SFC BASED AS THE SYSTEM ENCOUNTERS DEEPER LOW LEVEL MOISTURE.  ETA
FCST SOUNDINGS FOR SATURDAY AFTERNOON DEPICT PWS NEAR AN INCH WITH
WET BULB ZERO HEIGHTS BELOW 8K FEET. THIS BODES WELL FOR HAIL
PRODUCING TSTMS IN THE AFTERNOON AND EVENING HOURS FOR THE EASTERN
HALF OF THE CWFA. THE UPPER LEVEL SYSTEM IS A FAST MOVER WITH THE
CONVECTION EAST OF THE CWFA BY EARLY SUNDAY MORNING.

SHALLOW MOISTURE RETURN WILL OCCUR SUNDAY NIGHT INTO MONDAY MORNING
AS THE SURFACE RIDGE SHIFTS EASTWARD TO THE EAST COAST. THIS WILL
RESULT IN SOME PATCHY FOG SOUTH AND EAST OF THE BALCONES ESCARPMENT.
THE NEXT SHORTWAVE TROF WILL ENTER THE 4 CORNERS REGION ON TUESDAY.
THIS WILL INCREASE LOW LEVEL MOISTURE UP THE RIO GRANDE VALLEY WITH
MORNING FOG AND DRIZZLE POSSIBLE.  AS THE SHORTWAVE SWINGS SOUTHEAST
ACROSS TEXAS ON TUESDAY AN ATTENDANT COLD FRONT WILL MOVE THRU THE
CWFA.  SCATTERED SHOWERS AND THUNDERSTORMS WILL PRECEDE AND
ACCOMPANY THE FRONTAL PASSAGE TUESDAY INTO TUESDAY NIGHT.  HIGH
PRESSURE AT THE SFC AND ALOFT WILL KEEP THINGS DRY WEDNESDAY AND
THURSDAY.  PCPN CHANCES RETURN AGAIN ON FRIDAY WITH THE APPROACH OF
A DEEP UPPER LEVEL TROF.

TXZ171>173-183>194-202>209-217>225-228-221100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
520 AM CST FRI MAR 21 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY

AN UPPER TROUGH ENTERING WEST TEXAS LATE TONIGHT...ALONG WITH
INCREASING MOISTURE FROM THE GULF OF MEXICO WILL RESULT IN ISOLATED
THUNDERSTORMS MAINLY OVER THE WESTERN SECTIONS OF SOUTH CENTRAL
TEXAS LATE TONIGHT.  SOME OF THESE THUNDERSTORMS COULD PRODUCE LARGE
HAIL.

.SPOTTER INFORMATION STATEMENT...

DUE TO THE ISOLATED COVERAGE OF THESE STORMS...SPOTTER ACTIVATION IS
NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...

AN UPPER TROUGH OVER WEST TEXAS SATURDAY WILL CONTINUE MOVING
EAST ACROSS TEXAS...PRODUCING ISOLATED THUNDERSTORMS OVER MUCH OF
SOUTH CENTRAL TEXAS AND THE HILL COUNTRY.  SOME OF THE STORMS WILL
BE CAPABLE FOR PRODUCING LARGE HAIL.

SCATTERED THUNDERSTORMS ARRIVING FROM THE WEST ARE EXPECTED LATE
TUESDAY THROUGH THURSDAY...AND A FEW STORMS COULD BE SEVERE.