Severe Thunderstorm Warning 15, NWS Austin/San Antonio, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
1012 AM CDT TUE MAR 13 2007

.DISCUSSION...
CONTINUED GOOD CHANCE OF RAIN EXPECTED THROUGH WEDNESDAY
MORNING...WITH LOCALLY HEAVY RAIN STILL POSSIBLE.  WILL
KEEP FLASH FLOOD WATCH THRU 7 AM WEDNESDAY MORNING.
LOW ALOFT NEAR THE SE CORNER OF NEW MEXICO IS FORECAST
TO MOVE EAST ACROSS TEXAS TONIGHT AND WEDNESDAY MORNING.
AHEAD OF THIS MARCH RAIN MAKER...OCCASIONAL RAIN WILL
CONTINUE FORMING TODAY AND TONIGHT...WITH SHOWERS AND
THUNDERSTORMS. THIS AREA OF RAIN WILL SLOWLY MOVE EAST
LATER TODAY AND TONIGHT...THRU WEDNESDAY MORNING...AS
THE LOW ALOFT IS CARRIED EAST. BY WEDNESDAY AFTERNOON A
COMPOSITE OF SOLUTIONS SINCE THE WEEKEND SHOWS THE LOW
MOVING EAST OF THE AREA...SIGNALING DECREASING CLOUDS
AND RAIN CHANCES FROM THE WEST BEGINNING WEDNESDAY MORNING
AND CONTINUING THRU WEDNESDAY AFTERNOON.

MORE STABLE CONDITIONS EVOLVING QUICKLY FROM THE WEST
WEDNESDAY NIGHT AND THURSDAY MORNING. THIS MAY HELP
PATCHY FOG FORM OVER PART OF THE AREA THURSDAY MORNING...
THEN MIXING OUT TO A MOSTLY SUNNY AND WARM DAY THURSDAY...
AHEAD OF A COLD FRONT FORECAST TO MOVE ACROSS THE AREA ON
THURSDAY NIGHT THROUGH FRIDAY. INITIALLY CLOUDS MAY COME
WITH THE COLD FRONT AND AN ASSOCIATED S/W TROF COMING
FROM THE N AND NW. CLEARING EXPECTED IN THE DAY FRIDAY
AND FRIDAY NIGHT IN WAKE OF THIS PROGRESSIVE MOVING
WEATHER SYSTEM. A MOSTLY SUNNY TO PARTLY CLOUDY DAY
IS EXPECTED SATURDAY.  INCREASING CLOUDS ARE EXPECTED
SATURDAY NIGHT THROUGH MONDAY...AS SOUTHERLY WINDS
RETURN AND INCREASE.

MEDIUM RANGE TOOLS SHOW ANOTHER WINDOW FOR RAIN OPENING
UP IN THE WEEK OF MAR 19 TO MAR 24. ONE WINDOW COULD COME
WITH A WEAK COOL FRONT IN THE MIDDLE OF NEXT WEEK AND
ANOTHER WINDOW FOR RAIN SHOWS UP LATE NEXT WEEK TO THE
WEEKEND OF MARCH 24 AND 25...AS A 500 HPA LOW IS FORECAST
TO APPROACH THE AREA FROM THE WEST.

&&

.PREV DISCUSSION... /ISSUED 634 AM CDT TUE MAR 13 2007/

AVIATION...
AREAS OF IFR AND MVFR CIGS WILL PREVAIL UNTIL 15Z...WITH VFR
CONDITIONS THEREAFTER. THUNDERSTORMS MAY DEVELOP BY 18Z...BUT WILL
BE WIDESPREAD BY 21Z THIS AFTERNOON AND CONTINUE UNTIL AT LEAST
03Z WEDNESDAY BEFORE DIMINISHING OR MOVING EAST. MVFR CIGS WILL
COME BACK TUESDAY NIGHT. A LIGHT TO MODERATE SOUTHERLY LOW LEVEL
FLOW WILL CONTINUE.

PREV DISCUSSION... /ISSUED 350 AM CDT TUE MAR 13 2007/

DISCUSSION...LARGE UPPER LEVEL LOW PRESSURE IS QUASI-STATIONARY
OVER THE WEST TEXAS/NEW MEXICO BORDER THIS MORNING. LOOKING AT THE
WATER VAPOR IMAGERY THIS FEATURE IS QUITE IMPRESSIVE. THIS SYSTEM
WILL BEGIN TO TRACK EASTWARD TODAY AND TONIGHT ACROSS TEXAS.
CURRENTLY ON RADAR...THERE ARE SHOWERS AND THUNDERSTORMS IN OUR
NORTHEASTERN COUNTIES. THESE SHOWERS AND THUNDERSTORMS HAVE BEEN
PROPOGATING...REFORMING...AND TRAINING OVERNIGHT. THE UPPER RAIN
AMOUNTS OVERNIGHT...ACCORDING TO RADAR ESTIMATION...ARE AROUND 3
INCHES IN WILSON AND GONZALES COUNTIES.

AS THE UPPER LOW PROGRESSES EASTWARD TODAY AND TONIGHT...MANY
SHORTWAVES WILL ROTATE AROUND THE UPPER LOW...CONTINUING TO BRING
WAVES OF SHOWERS AND THUNDERSTORMS TO THE REGION. PW AMOUNTS ARE
RUNNING VERY SIMILAR TO YESTERDAY MORNING...WITH 0.84 INCHES AT
KDRT AND 1.53 INCHES AT KCRP. AMPLE MOISTURE IS IN PLACE ALONG
WITH AMPLE LIFT FROM THE UPPER LOW. THEREFORE FLASH FLOODING IS A
THREAT FOR THE NEXT 24 HOURS...AT LEAST. WE WILL ISSUE A FLASH
FLOOD WATCH FOR THE EASTERN HALF OF OUR CWFA. IN CONJUNCTION WITH
THE THREAT TO FLASH FLOODING...WE ALSO HAVE A SLIGHT RISK FOR
SEVERE THUNDERSTORMS FOR TODAY AS WELL.

THE UPPER LOW WILL FINALLY MAKE ITS EXIT OUT OF TEXAS LATE WEDNESDAY.
THIS WILL BRING AN END TO THE RAIN CHANCES BY WEDNESDAY EVENING
FOR SOUTH CENTRAL TEXAS. SKIES WILL CLEAR BEHIND THE SYSTEM AND
WINDS WILL BE CALM WEDNESDAY NIGHT. DUE TO SATURATED
GROUNDS...THIS WILL BE THE PERFECT SET UP FOR FOG. SO HAVE
INCLUDED FOG IN THE FORECAST LATE WEDNESDAY NIGHT/THURSDAY
MORNING. A COLD/DRY FRONT IS FORECAST TO MOVE THROUGH THE AREA
SOMETIME THURSDAY NIGHT...ALTHOUGH THE MODELS DIFFER IN THEIR
SOLUTIONS. HAVE GONE MORE WITH A CONSENSUS FORECAST AND BROUGHT
THE FRONT THROUGH THE REGION...ALONG THE LINES OF THE NAM12 AND
ECMWF. THIS WILL MEAN WARM TEMPERATURES AHEAD OF THE FRONT ON
THURSDAY...THEN COOLER TEMPERATURES ON FRIDAY POST FROPA. AFTER
THE FRONTAL PASSAGE...TEMPERATURES WILL BE CLOSER TO SEASONAL
NORMALS FOR THE REMAINDER OF THE FORECAST PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
AUSTIN CAMP MABRY              73  63  79  59  84 /  70  80  50  -    0
AUSTIN BERGSTROM INTL AIRPORT  73  60  78  55  81 /  70  80  50  -    0
DEL RIO INTL AIRPORT           78  60  86  59  89 /  60  30  10  -   -
SAN ANTONIO INTL AIRPORT       73  63  81  61  85 /  70  70  40  -    0

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH THROUGH WEDNESDAY MORNING FOR THE FOLLOWING
ZONES: ATASCOSA...BANDERA...BASTROP...BEXAR...BLANCO...BURNET...
CALDWELL...COMAL...DE WITT...FAYETTE...FRIO...GILLESPIE...
GONZALES...GUADALUPE...HAYS...KARNES...KENDALL...KERR...LAVACA...
LEE...LLANO...MEDINA...TRAVIS...WILLIAMSON...WILSON.

&&

08/25/DC

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE AUSTIN/SAN ANTONIO TX
537 AM CDT TUE MAR 13 2007

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-
537 AM CDT TUE MAR 13 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL TEXAS.

.DAY ONE...TODAY AND TONIGHT
THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS TODAY AND TONIGHT
ACROSS ALL OF SOUTH CENTRAL TEXAS...WITH LARGE HAIL AND DAMAGING
WINDS BEING THE PRIMARY THREATS. A FLASH FLOOD WATCH IS IN EFFECT
FOR THE EASTERN TWO-THIRDS OF SOUTH CENTRAL TEXAS THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION MAY BE NEEDED TODAY.