Severe Thunderstorm Warning 49, NWS Austin/San Antonio, TX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
640 AM CDT THU MAY 13 2010

.AVIATION...
MVFR CIGS WILL CONTINUE THROUGH MOST OF THIS FORECAST PERIOD.
AFTER 18Z TODAY WILL LIKELY SEE VFR CIGS UNTIL LOW CLOUDS RETURN
AFTER 05Z TONIGHT WITH MVFR CIGS ARE EXPECTED. WINDS WILL BE S/SE
TODAY AT 15 TO 25 KTS. E/SE WINDS NEAR 10 KTS AFTER 03Z. CURRENTLY
SEEING STRONG TO SEVERE THUNDERSTORMS ACROSS THE WESTERN PORTION
OF THE REGION. WILL LIKELY SEE ADDITIONAL SHOWERS AND
THUNDERSTORMS ACROSS THE ENTIRE AREA DURING THE AFTERNOON AND INTO
THE EVENING. HAVE INCLUDED TEMPO GROUPS DUE TO THE UNCERTAINTY
WITH TIMING.

&&

.PREV DISCUSSION... /ISSUED 402 AM CDT THU MAY 13 2010/

DISCUSSION...
THE MODELS ARE IN GENERAL AGREEMENT THROUGH THE NEXT SEVERAL DAYS.
TODAY THROUGH SUNDAY, AN UPPER LEVEL TROUGH SLOWLY MOVES ACROSS
THE WESTERN INTO THE CENTRAL STATES WHILE AN UPPER RIDGE DRIFTS
EAST ACROSS THE SOUTHEASTERN STATES. A SERIES OF WEAK SHORT-WAVES
AND UPPER JET SEGMENTS MOVE THROUGH THE FLOW ALOFT AS A SOUTHERLY
FLOW FROM THE GULF OF MEXICO KEEPS THE AIRMASS MOIST. HOWEVER, THE
MODELS STILL LACK A CONSENSUS ON THE TIMING AND TRACK OF THESE
SMALLER SCALE FEATURES THAT DETERMINE THE HIGHER POPS AND GREATER
QPF. POPS WILL MAINLY BE IN THE CHANCE CATEGORY WITH PERIODS OF
LOCALLY HEAVY RAINS AS PWS TO RISE UP TO 1.8 INCHES AT TIMES.
STILL EXPECT THAT SOME SPOTS MAY HAVE 3 TO 5 INCH RAINFALL TOTALS
BETWEEN TODAY AND SUNDAY. WHERE THESE SPOTS ARE WILL BE DETERMINED
BY MESO-SCALE INTERACTIONS WHICH IS UNCERTAIN AT THIS TIME. IF A
COLD FRONT MOVING SOUTHEAST ACROSS THE TEXAS SOUTH PLAINS AND A
DRYLINE OVER WESTERN TEXAS MOVE INTO SOUTH CENTRAL TEXAS, THEN QPF
WOULD BE ENHANCED AND POSSIBLY MORE WIDESPREAD. ON MONDAY, THE
TROUGH MOVES EAST WITH BRIEF UPPER LEVEL RIDGING. POPS DECREASE OR
END DUE TO SUBSIDENCE. TUESDAY THROUGH NEXT THURSDAY, MODELS NOW
SHOW ANOTHER UPPER LEVEL TROUGH APPROACHING TEXAS AND HAVE
INTRODUCED SLIGHT CHANCE POPS. MAV/MEX GUIDANCE TEMPERATURES SEEM
REASONABLE AND HAVE GENERALLY FOLLOWED.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              88  71  89  70  84 /  20  30  40  30  40
AUSTIN BERGSTROM INTL AIRPORT  88  72  89  68  83 /  20  30  40  30  40
NEW BRAUNFELS MUNI AIRPORT     89  71  90  69  85 /  20  30  40  40  40
BURNET MUNI AIRPORT            84  68  85  68  81 /  30  30  40  30  40
DEL RIO INTL AIRPORT           92  73  84  70  86 /  30  20  30  40  20
GEORGETOWN MUNI AIRPORT        86  69  86  69  82 /  20  30  40  30  40
HONDO MUNI AIRPORT             89  73  88  70  85 /  30  30  40  50  40
SAN MARCOS MUNI AIRPORT        89  71  88  69  85 /  20  30  40  30  40
LA GRANGE - FAYETTE REGIONAL   87  73  87  70  84 /  20  20  30  30  40
SAN ANTONIO INTL AIRPORT       88  72  89  70  84 /  30  30  40  40  40
STINSON MUNI AIRPORT           88  73  89  71  85 /  30  30  40  40  40

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

04/10

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
459 AM CDT THU MAY 13 2010

TXZ171>173-183>194-202>209-217>225-228-141100-
LLANO-BURNET-WILLIAMSON-VAL VERDE-EDWARDS-REAL-KERR-BANDERA-
GILLESPIE-KENDALL-BLANCO-HAYS-TRAVIS-BASTROP-LEE-KINNEY-UVALDE-
MEDINA-BEXAR-COMAL-GUADALUPE-CALDWELL-FAYETTE-MAVERICK-ZAVALA-
FRIO-ATASCOSA-WILSON-KARNES-GONZALES-DE WITT-LAVACA-DIMMIT-
459 AM CDT THU MAY 13 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT...
WIDELY SCATTERED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO BEGIN TO INCREASE ACROSS THE REGION THIS AFTERNOON AND
TONIGHT. AN ISOLATED STORM OR TWO COULD PRODUCE LARGE HAIL AND
DAMAGING WINDS...BUT THE GREATER THREAT WOULD BE LOCALIZED HEAVY
RAIN.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY...
FRIDAY INTO SUNDAY THE MOISTURE WILL CONTINUE TO INCREASE AS
SEVERAL DISTURBANCES CROSS THE REGION AND A FRONTAL BOUNDARY
BECOMES STATIONARY. THIS WILL ALLOW FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP. HEAVY RAINFALL WITH LOCALIZED FLOODING
WILL BE THE MAIN THREAT. RAINFALL TOTALS IN SOME LOCATIONS MAY BE
3 TO 5 INCHES. AT THIS TIME...IT IS UNCERTAIN ON THE LOCATION AND
TIMING OF THE HEAVY RAINS.

AFTER SUNDAY A DRIER PATTERN WILL DEVELOP.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME.