AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
956 AM CDT SAT MAY 25 2013
.UPDATE...
UPDATED FOR FFA ISSUANCE AS HEAVY RAIN EVENT HAS UNFOLDED RAPIDLY
THIS MORNING. WARM CORE PROCESSES HAVE A CHANCE TO PEAK AND
SUBSIDE WITH SLIGHTLY DECREASED ACTIVITY LATER TODAY...BUT THE
RAINS RECEIVED LAST NIGHT AND EARLY THIS MORNING HAS LEFT
EFFECTIVE FLASH FLOOD GUIDANCES TO WELL BELOW ONE INCH AND TO NEAR
ZERO AROUND SAN ANTONIO...AS LIFE THREATENING FLASH FLOODING IS
ALREADY UNDERWAY.
&&
.HYDROLOGY...
RIVER RISES IN THE SAN ANTONIO METRO AREA ARE BEHAVING AS A FLASH
FLOOD AND ARE REACHING HISTORICAL RECORDS AS SEEN AT THE SAN
ANTONIO RIVER AT LOOP 410. STREAMFLOW CONCERNS WILL GRADUALLY
SHIFT NORTH IN THE MIDDAY HOURS AS THE NNW/SSE AXIS OF THE
HEAVIEST RAINS DRIFTS NWD AT ONLY 15 MPH.
&&
.PREV DISCUSSION... /ISSUED 658 AM CDT SAT MAY 25 2013/
AVIATION...
FAVORABLE MODERATE INSTABILITY AND UPPER LEVEL DISTURBANCE MOVING
ACROSS THE EDWARDS PLATEAU AND HILL COUNTRY THIS MORNING WILL AID
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS TO PREVAIL ACROSS
THE I-35 CORRIDOR THROUGH LATE THIS AFTERNOON. MVFR/IFR CIGS ARE
EXPECTED AS STORMS MOVE ACROSS THE AIRPORT SITES WITH GUSTY WINDS
UP TO 28 KNOTS. WEATHER CONDITIONS WILL IMPROVE THIS AFTERNOON AS THE
UPPER TROUGH MOVES TO CENTRAL TEXAS AND A DRY AIRMASS MOVES ACROSS
THE AREA FROM THE WEST. ACROSS KDRT...MVFR CONDITIONS ARE EXPECTED
THIS MORNING WITH VFR RETURNING AFTER 18Z THIS AFTERNOON.
PREV DISCUSSION... /ISSUED 333 AM CDT SAT MAY 25 2013/
SHORT TERM (TODAY THROUGH SUNDAY)...
A WEAK UPPER LEVEL TROUGH SLOWLY MOVES ACROSS THE AREA TODAY INTO
TONIGHT. HI-RES MODELS SHOW SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ACROSS MUCH OF THE AREA WITH LESS COVERAGE ALONG THE
RIO GRANDE. PWS IN THE 1.4 TO 1.8 INCH RANGE INDICATE LOCALLY
HEAVY RAINFALL IS POSSIBLE. RAINFALL AMOUNTS RANGE FROM LESS THAN
1/10 INCH OUT WEST TO 1/4 TO 1 INCH WITH ISOLATED TOTALS OF 2 TO 4
INCHES EAST. CAN NOT RULE OUT SOME GUSTY WINDS AND SMALL HAIL WITH
THE STRONGER STORMS. ON SUNDAY...AN UPPER LEVEL RIDGE STARTS TO
BUILD INTO TEXAS FROM MEXICO. RESIDUAL DEEPER MOISTURE ALLOWS FOR
ISOLATED SHOWERS AND THUNDERSTORMS TO DEVELOP. DUE TO CLOUDS AND
RAIN...TEMPERATURES WILL BE SLIGHTLY BELOW AVERAGE.
LONG TERM (SUNDAY NIGHT THROUGH FRIDAY)...
THE UPPER LEVEL RIDGE BUILDS A LITTLE MORE BY MONDAY WITH NO RAIN
DUE TO SUBSIDENCE AND SLIGHTLY LESS MOISTURE. THE UPPER LEVEL
RIDGE WEAKENS TUESDAY THROUGH THURSDAY AS AN UPPER LEVEL TROUGH
PASSES BY TO THE NORTH ACROSS THE SOUTHERN ROCKIES INTO SOUTHERN
PLAINS. DEEPER MOISTURE RETURNS AS MID LEVEL FLOW TURNS SOUTHERLY.
EXPECT ISOLATED SHOWERS AND THUNDERSTORMS OUT WEST TUESDAY
EVENING AND WEDNESDAY AFTERNOON INTO WEDNESDAY NIGHT SPREADING TO
ALL AREAS THURSDAY INTO THURSDAY NIGHT. ON FRIDAY...SUBTROPICAL
RIDGE BEGINS TO STRONGLY BUILD OVER THE AREA WITH NO RAIN CHANCES.
TEMPERATURES CLOSER TO AVERAGE CAN BE EXPECTED.
&&
.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY 86 71 91 71 91 / 80 20 10 - -
AUSTIN BERGSTROM INTL AIRPORT 86 69 89 70 90 / 80 20 10 - -
NEW BRAUNFELS MUNI AIRPORT 86 70 91 71 90 / 80 20 10 - -
BURNET MUNI AIRPORT 84 68 88 69 89 / 80 20 10 - -
DEL RIO INTL AIRPORT 88 73 92 73 95 / 20 20 10 - -
GEORGETOWN MUNI AIRPORT 84 69 88 70 88 / 80 20 10 - -
HONDO MUNI AIRPORT 88 71 91 71 93 / 60 20 10 - -
SAN MARCOS MUNI AIRPORT 86 70 90 71 90 / 80 20 10 - -
LA GRANGE - FAYETTE REGIONAL 85 71 89 71 89 / 50 20 10 - -
SAN ANTONIO INTL AIRPORT 87 72 90 72 91 / 80 20 10 - -
STINSON MUNI AIRPORT 87 71 90 72 91 / 80 20 10 - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 PM CDT THIS EVENING FOR THE FOLLOWING
COUNTIES: ATASCOSA...BASTROP...BEXAR...BLANCO...BURNET...CALDWELL...
COMAL...DE WITT...FAYETTE...GILLESPIE...GONZALES...GUADALUPE...
HAYS...KARNES...KENDALL...LAVACA...LEE...LLANO...TRAVIS...
WILLIAMSON...WILSON.
&&
$$
MESOSCALE/AVIATION...02
SYNOPTIC/GRIDS...18
PUBLIC SERVICE/DATA COLLECTION...30
