Severe Thunderstorm Warning 99, NWS Austin/San Antonio, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
430 AM CDT TUE MAY 11 2004

.DISCUSSION...
PRECIPITABLE WATER VALUES ARE EXPECTED TO APPROACH 1.8 IN ACROSS
CENTRAL AND EASTERN PARTS OF THE FORECAST AREA TODAY. THUS WITH A
SLOW MOVING DISTURBANCE TRIGGERING NUMEROUS THUNDERSTORMS AND
SATURATED SOILS, HAVE OPTED FOR A FFA FOR THIS AREA. SOME LOCALIZED
FLOODING IS ALSO POSSIBLE OVER WESTERN SECTIONS THROUGH DAYBREAK, BUT
EXPECT CONDITIONS TO IMPROVE BY THAT TIME. RAINFALL AMOUNTS ARE
EXPECTED TO AVERAGE CLOSE TO 1 INCH OVER THE WATCH AREA WITH SPOTTY
3 INCH AMOUNTS POSSIBLE. SEVERE THREAT SHOULD BE MINIMAL SINCE THE
UPPER DISTURBANCE NOT PRODUCING STRONG WIND SHEAR AND HIGH
PRECIPITABLE WATER VALUES DOESNT USUALLY SUPPORT HAILSTORMS.
THIS DISTURBANCE SHOULD START TO PULL AWAY FROM SOUTH CENTRAL TEXAS
BY LATE THIS AFTERNOON. LAPSE RATES COULD BE STEEP ENOUGH TO SUPPORT
EVENING CONVECTION, BUT STABILITY SHOULD INCREASE WITH THE LOSS OF
HEATING.

THE NEXT WEATHER SYSTEM IS NOT FAR BEHIND SO A MOSTLY CLOUDY DAY
WEDNESDAY SHOULD GIVE WAY TO MORE CONVECTION THURSDAY THROUGH FRIDAY
NIGHT. THIS LARGER TROUGH WILL PASS MAINLY TO THE NORTH OF THE AREA
BUT SHOULD SET OFF AN MCS LATE FRIDAY INTO SATURDAY MORNING. THIS
WILL BRING A WIND SHIFT/WEAK FRONT, BUT SHOULD NOT MODIFY THE AIR
TOO MUCH. THE CONTINUED ZONAL PATTERN SHOULD SUPPORT ISOLATED POPS
OVER THE WEEKEND WITH UPPER RIDGING FINALLY EXPECTED TO TAKE OVER ON
TUESDAY. HOWEVER, POOR RUN TO RUN CONSISTENCY FROM BOTH THE GFS AND
ECMWF LEADS TO A CONTINUED LOW CONFIDENCE EXTENDED, LARGELY DUE TO
THE ACTIVE SUBTROPICAL JET.

AT LEAST TEMPS ARE MORE PREDICTABLE WITH LOW DIURNAL RANGES AND AT OR
BELOW NORMAL HIGHS A GOOD BET.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              80  69  84  68 /  80  30  10  10
AUSTIN BERGSTROM INTL AIRPORT  80  68  84  68 /  80  30  10  10
DEL RIO INTL AIRPORT           86  70  87  70 /  40  20  10  10
SAN ANTONIO INTL AIRPORT       80  69  84  70 /  80  20  10  10

&&

.EWX WATCHES/WARNINGS/ADVISORIES...FFA CENTRAL AND EASTERN PARTS OF
SOUTH CENTRAL TX

&&

18/08

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
524 AM CDT TUE MAY 11 2004

TXZ171>173-183>194-202>209-217>225-228-121100-
ATASCOSA-BANDERA-BASTROP-BEXAR-BLANCO-BURNET-CALDWELL-COMAL-DE WITT-
DIMMIT-EDWARDS-FAYETTE-FRIO-GILLESPIE-GONZALES-GUADALUPE-HAYS-KARNES-
KENDALL-KERR-KINNEY-LAVACA-LEE-LLANO-MAVERICK-MEDINA-REAL-TRAVIS-
UVALDE-VAL VERDE-WILLIAMSON-WILSON-ZAVALA-

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT.
SHOWERS AND THUNDERSTORMS ARE LIKELY OVER SOUTH CENTRAL TEXAS
TODAY...AS A MID MAY RAIN MAKING SYSTEM ALOFT MOVES OVER THE AREA.
A FLASH FLOOD WATCH IS IN EFFECT THROUGH 400 PM CDT...ALONG AND
EAST OF A LLANO TO HONDO TO DILLEY LINE.  THIS INCLUDES THE AUSTIN
AND SAN ANTONIO AREAS.  LOCALLY HEAVY RAIN IS POSSIBLE.

THERE IS A CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE EAST PART OF
SOUTH CENTRAL TEXAS THIS EVENING DECREASING TO A SLIGHT CHANCE OF
SHOWERS DURING THE NIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

THERE IS A SLIGHT CHANCE OF SHOWERS WEDNESDAY OVER EASTERN PARTS
OF SOUTH CENTRAL TEXAS.

FOR THURSDAY THROUGH FRIDAY NIGHT THERE IS AN INCREASING CHANCE OF
SHOWERS AND THUNDERSTORMS...AS ANOTHER RAIN MAKING SYSTEM PASSES OVER
THE AREA FROM THE WEST.

A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS IS EXPECTED SATURDAY
THROUGH MONDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED REQUIRED TODAY WHERE HEAVY RAIN
AMOUNTS ARE OBSERVED OR DEVELOP.