Flash Flood Warning 47, NWS Austin/San Antonio, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
558 AM CDT MON JUN 28 2010

.AVIATION...
TROPICAL MOISTURE ACROSS S CENTRAL TX AND THE HILL COUNTRY TODAY
WILL RESULT IN SCT-NUMEROUS SHRA/TSRA ACROSS THE AREA FOR THE NEXT
24 HOURS. MVFR CIGS PREVAILING THIS MORNING AND AGAIN LATE
TONIGHT...BUT LIFTING TO VFR THIS AFTERNOON...EXCEPT CONTINUING
IFR/MVFR IN THE STORMS. A LIGHT TO MODERATE SE-E LOW LEVEL FLOW
WILL PERSIST.

&&

.PREV DISCUSSION... /ISSUED 515 AM CDT MON JUN 28 2010/

DISCUSSION...
A DEVELOPING HEAVY RAINFALL EVENT HAS BEGUN OVER THE WESTERN PART
OF THE FORECAST AREA...PROMPTING AN EARLY MORNING FFA ISSUANCE. A
BROAD MID-LEVEL ROTATION HAS DEVELOPED OVER MUCH OF TEXAS...MAINLY
THE NW HALF. MUCH OF THE PAST MODEL PROJECTIONS HAD MOST OF THE
HEAVY RAIN AFFECTING WEST CENTRAL TEXAS WITH ONLY ISOLATED HEAVY
RAIN AREAS EXTENDING EAST INTO OUR AREA. THE EARLY MORNING
CONVECTION THAT SPUN UP AROUND BRACKETTVILLE HAS SHIFTED SOME OF
THE FOCUS EAST. THE BROAD PATTERN IS ENHANCED BY A AN UPPER LOW
OVER THE SONORAN DESERT WHICH HAS FURTHER DESTABILIZED CONDITIONS
BY TRANSPORTING A PACIFIC TROPICAL PLUME INTO THE AREA. WITH A
BROAD AREA OF INSTABILITY AN MOISTURE POOLED OVER WESTERN AND
CENTRAL TEXAS...THE FIRST FFA IS A BIT CONSERVATIVE...ENDING AT
MIDNIGHT AND FOCUSED WELL WEST OF THE I-35 CORRIDOR. HOWEVER...IT
IS LIKELY SOME AREAS OF HEAVY RAIN COULD EXPAND FARTHER EAST AND
PROLONG INTO TUESDAY. A SHARP RIDGE AXIS ALSO SITS OVER CENTRAL
TX AND SHOULD LIMIT THE EASTWARD PROGRESSION OF THE HEAVY RAIN
FOCUS. ANOTHER REASON NOT TO PUSH THE WATCH FARTHER EAST AND
INTO LATER PERIODS IS THE DEVELOPING CONCERN OVER THE GULF. THE
TPC INDICATES A FAIRLY AGRESSIVE STRENGTHENING OF ALEX...AT LEAST
BY JUNE STANDARDS. THIS RAPID STRENGTHENING COULD ENHANCE A DRIER
E/NE WIND AND SHIFT THE CONVECTIVE FOCUS BACK TO THE NW BY
TUESDAY.

BEYOND TUESDAY...AN UNCERTAIN AND UNSTABLE FORECAST IS DEPICTED
FOR THIS MORINGS PACKAGE WITH THE TPC PROJECTED TRACK OF ALEX
SHIFTING EVER CLOSER TO A BROWNSVILLE LANDFALL WITH EACH UPDATE.
A SIGNIFICANT PORTION OF MODEL SOLUTIONS...INCLUDING THE GFS
MAINTAIN A TRACK DRAGGING NORTH INTO CENTRAL TEXAS. THUS MUCH OF
THE FORECAST THIS MORNING IS IN A BLEND TOWARD THE TPC SOLUTION
WITH A LATE WEEK BLEND OF THE GFS FORECAST. THIS WOULD IMPLY A
COOLER AND WETTER SOLUTION THAN WHAT WOULD HAPPEN IF THE TPC TRACK
VERIFIES AT ITS CURRENT POSITION. GIVEN THE POTENTIAL MAJOR
FLOODING IMPACTS THAT COULD EVOLVE IF THE FORECAST TRACK CONTINUES
TO SHIFT NORTHWARD...A TIP TOWARD THE WETTER AND COOLER GFS IS
WARRANTED. POPS BASED PURELY ON THE TPC FORECAST WILL MOST LIKELY
BE SIMILAR WITH MUCH OF SOUTH CENTRAL GETTING A GOOD SHOT OF RAIN
THURSDAY NIGHT INTO FRIDAY...BUT THE HEAVY RAIN MENTION IN OUR
FORECAST COVERS A BROADER SCOPE.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              95  75  94  76  92 /  30  50  40  20  40
AUSTIN BERGSTROM INTL AIRPORT  95  74  93  76  91 /  30  40  40  20  40
NEW BRAUNFELS MUNI AIRPORT     95  75  94  76  92 /  30  40  40  20  40
BURNET MUNI AIRPORT            90  72  88  72  91 /  50  60  50  20  30
DEL RIO INTL AIRPORT           92  73  92  74  93 /  40  50  40  30  20
GEORGETOWN MUNI AIRPORT        94  74  92  73  91 /  40  50  40  20  30
HONDO MUNI AIRPORT             93  74  93  75  93 /  30  60  40  20  30
SAN MARCOS MUNI AIRPORT        95  75  94  75  91 /  30  40  40  20  40
LA GRANGE - FAYETTE REGIONAL   95  76  94  76  91 /  30  30  30  20  40
SAN ANTONIO INTL AIRPORT       95  76  94  76  92 /  30  50  40  20  40
STINSON MUNI AIRPORT           96  77  95  77  93 /  30  40  30  20  40

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH THIS EVENING FOR THE FOLLOWING COUNTIES:
BANDERA...EDWARDS...GILLESPIE...KENDALL...KERR...KINNEY...LLANO...
MAVERICK...MEDINA...REAL...UVALDE...VAL VERDE.

&&

01/18

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
458 AM CDT MON JUN 28 2010

TXZ171>173-183>194-202>209-217>225-228-291000-
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-
458 AM CDT MON JUN 28 2010

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT...
A FLASH FLOOD WATCH IN EFFECT FOR MUCH OF THE HILL COUNTRY...EDWARDS
PLATEAU AND RIO GRANDE PLAINS THROUGH MIDNIGHT TONIGHT. A COMBINATION
OF TROPICAL MOISTURE FROM THE PACIFIC AND GULF MOISTURE...INTERACTING
WITH A WEAK FRONTAL SYSTEM TO THE NORTH WILL BRING SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS TO THE AREA TODAY AND TONIGHT.
LOCALLY HEAVY RAINFALL AMOUNTS OF 2 TO 4 INCHES ARE POSSIBLE
ACROSS THE WATCH AREA.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY...
TROPICAL STORM ALEX IS FORECAST TO BECOME A HURRICANE IN THE
WESTERN GULF OF MEXICO AND MOVE INLAND SOUTH OF BROWNSVILLE AT
THIS TIME. IF ALEX MOVES INLAND FURTHER NORTH ALONG THE TEXAS
COAST...THREATS ASSOCIATED WITH LAND FALLING HURRICANES MAY AFFECT
PORTIONS OF SOUTH CENTRAL TEXAS LATE THURSDAY INTO FRIDAY AND
SATURDAY. IN PARTICULAR...THE THREAT OF INLAND FLOODING DUE TO
EXCESSIVE RAINFALL WOULD BE ON THE INCREASE.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE REQUIRED TODAY OR THIS EVENING.