Severe Thunderstorm Warning 56, NWS Corpus Christi, TX

SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
904 PM CDT THU SEP 11 2003

SHORT-TERM(TONIGHT THRU FRI)...ISOLATED CONVECTION ACROSS THE CWA
LATE THIS AFTERNOON/EVENING BEING FORCED BY A 500HPA VORTICITY
MAXIMUM. AREAL COVERAGE IS BEING LIMITED BY A STRONG LOW-LEVEL JET.
MSAS/LAPS/SOUNDING DATA INDICATES A VERY MOIST AND UNSTABLE
ATMOSPHERE RESIDES OVER THE CWA AND WILL PERSIST THROUGH THE
OVERNIGHT HOURS. AN OUTFLOW BOUNDARY PRECEDING A SQUALL LINE ACROSS
THE HILL COUNTRY POTENTIALLY EXTRAPOLATES THROUGH THE CWA BY 09Z.
THE ACTUAL COLD FRONT LAGS ABOUT 85 MILES BEHIND THE MESOSCALE
BOUNDARY. WITH ADDITIONAL 500HPA SHORTWAVE ENERGY DROPPING INTO THE
BACK SIDE OF A 500HPA LONGWAVE TROUGH AND THE UPPER-LEVEL FLOW
BACKING TO THE SOUTHWEST...WOULD EXPECT THE COLD FRONT TO EVENTUALLY
DECELLERATE SOME. STRENGTHENING LOW-LEVEL JET ENHANCED BY
ISALLOBARIC TENDENCIES WILL CONTINUE TO FEED COPIOUS MOISTURE AND
INSTABILITY INTO THE MESOSCALE/MACROSCALE BOUNDARIES THROUGH FRIDAY.
SEVERAL PARAMETERS SUPPORT THE CONTINUATION OF THE FLASH FLOOD WATCH
BUT FEEL IT SHOULD BE EXPANDED TO INCLUDE THE WESTERN THREE COUNTIES
AS WELL. CURRENT GRIDDED FORECASTS INCORPORATED THE GFS WHICH IS
STILL THE MODEL OF CHOICE. ONLY ADJUSTMENTS TO CONSIDER WOULD BE THE
WINDS AND TEMPERATURES. TEMPERATURES NORTH OF THE MESOSCALE BOUNDARY
WERE RUNNING COOLER THAN MODEL GUIDANCE AND WILL LOWER SOME.
ADJUSTMENT TO THE WINDS REVOLVES AROUND THE OUTFLOW BOUNDARY BUT MAY
BE DIFFICULT TO DEPICT IN THE GRIDS DUE TO THE EVANESCENCE NATURE.
SCEC/SCA CONDITIONS WILL CONTINUE ACROSS THE WATERS DUE TO THE
AFOREMENTIONED WIND PARAMETERS.

.CRP...SCA GMZ250-255-270-275.
       FLASH FLOOD WATCH TXZ229>234-239>247 THROUGH 18Z FRI.

85/SHORT-TERM

GMZ230-235-250-255-270-275-TXZ229>234-239>247-121100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
545 AM CDT THU SEP 11 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH TEXAS.

.DAY ONE...TODAY AND TONIGHT
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED TODAY OF THE
COASTAL BEND AND VICTORIA AREA...WITH ISOLATED ACTIVITY OVER THE RIO
GRANDE PLAINS.  ALSO...SCATTERED TO NUMEROUS SHOWERS AND
THUNDERSTORMS ARE EXPECTED OVERNIGHT MAINLY OVER THE NORTHERN
COASTAL BEND AND VICTORIA AREAS...AS AN UPPER LEVEL LOW APPROACHES
SOUTH TEXAS. THE MAIN CONCERN WILL BE LOCALLY HEAVY RAINFALL...
WITH ISOLATED AMOUNTS AROUND 3 INCHES POSSIBLE BY SUNRISE ON FRIDAY.
HOWEVER...MOST LOCATIONS WILL AVERAGE AROUND 1/2 INCH.  A FEW STRONG
THUNDERSTORMS...PRODUCING WIND GUSTS OF 50 MPH AND PEA TO MARBLE
SIZED HAIL...ARE ALSO POSSIBLE MAINLY THIS AFTERNOON.  FINALLY...
AFTERNOON HEAT INDICES ARE EXPECTED TO RISE TO BETWEEN 105 AND 109
DEGREES OVER INLAND SECTIONS OF THE COASTAL BEND...VICTORIA AREA
AND RIO GRANDE PLAINS.  OTHERWISE...NO HAZARDOUS WEATHER IS EXPECTED.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

AN UPPER LEVEL DISTURBANCE AND ASSOCIATED COLD FRONT WILL APPROACH
SOUTH TEXAS AND THE ADJACENT WATERS ON FRIDAY. AS A RESULT...SHOWERS
AND THUNDERSTORMS WILL INCREASE IN COVERAGE LATE THURSDAY NIGHT INTO
FRIDAY MORNING ACROSS SOUTH TEXAS AND SPREAD EAST THROUGHOUT THE
DAY. VERY HEAVY RAIN...FREQUENT LIGHTNING AND GUSTY WINDS WILL
ACCOMPANY THESE SHOWERS AND THUNDERSTORMS. WIDESPREAD RAINFALL
AMOUNTS OF 2 TO 3 INCHES...WITH LOCALLY HIGHER AMOUNTS...WILL BE
POSSIBLE LATE THURSDAY NIGHT THROUGH FRIDAY NIGHT...WITH THE HEAVIEST
RAIN OCCURRING ACROSS THE NORTHERN COASTAL BEND AND VICTORIA
CROSSROADS REGION. THE WEAK COLD FRONT WILL PUSH OFFSHORE ON SATURDAY
WITH RAIN CHANCES DECREASING FROM WEST TO EAST SATURDAY MORNING. A
STRONGER SURGE OF DRIER AIR WILL PUSH THROUGH THE AREA LATE SUNDAY.
MODERATE TO OCCASIONALLY STRONG NORTH WINDS ARE EXPECTED BEHIND THIS
SECOND FRONT. SMALL CRAFT ADVISORIES MAY BE NEEDED AS A RESULT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

GW/JR

TXZ229>234-239>244-246-120730-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
1217 AM CDT FRI SEP 12 2003

...LINE OF SHOWERS AND STRONG THUNDERSTORMS HEADING FOR THE COASTAL
BEND...

AT 1215 AM...WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF
SHOWERS AND STRONG THUNDERSTORMS FROM PEARSALL TO FALLS CITY TO
CUERO.  THIS LINE WAS MOVING TO THE SOUTH AT 20 MPH.

AT THIS PRESENT MOVEMENT...THIS LINE WILL REACH THE NORTHERN SECTIONS
OF THE VICTORIA AREA AND COASTAL BEND AROUND 1 AM...THEN CONTINUE TO
MOVE SOUTH...REACHING THE CORPUS CHRISTI AND LAREDO AREAS AROUND 6
AM. THE THUNDERSTORMS WILL PRODUCE WIND GUSTS TO 50 MPH...VERY HEAVY
RAINFALL...CAUSING LOCALIZED FLOODING...AND POSSIBLY SMALL HAIL.
ONE OR TWO THUNDERSTORMS COULD PRODUCE WIND GUSTS IN EXCESS OF 55
MPH.  THE MAIN CONCERN WITH THESE SHOWERS AND STORMS HOWEVER...WILL
BE VERY HEAVY RAINFALL.  RAINFALL AMOUNTS OF 2 TO 3 INCHES WILL BE
COMMON...WITH LOCALLY HIGHER AMOUNTS.

RESIDENTS SHOULD CONTINUE TO MONITOR THE WEATHER AND LATEST
FORECASTS. REMAIN INDOORS AND STAY AWAY FROM WINDOWS AS THESE
THUNDERSTORMS APPROACH. IF FLOODING IS OBSERVED OR IF A FLOOD
WARNING IS ISSUED...MOVE TO HIGHER GROUND. DO NOT DRIVE INTO AREAS
WHERE WATER OF UNKNOWN DEPTH COVERS THE ROAD...ESPECIALLY AT NIGHT.

STAY TUNED TO NOAA WEATHER RADIO FOR FURTHER STATEMENTS OR
POSSIBLE WARNINGS. ALSO...CHECK OUT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/CRP

GW