Severe Thunderstorm Warning 55, NWS Corpus Christi, TX

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

SHORT-TERM (TONIGHT THROUGH FRIDAY NIGHT)...
UPPER LEVEL TROF PROGGED TO DIG SOUTHWARD INTO THE STATE AS STRONG
SHORTWAVE ROTATES AROUND THE BASE LATE TONIGHT.  VARIOUS MODEL
SOLUTIONS ARE SOMEWHAT HAZY AND THE ETA/NGM ARE CONSIDERABLY SLOWER
THAN GFS/UKMET/ECMWF.  CONCUR WITH EWX FORECASTER THAT THE FASTER
SOLUTION IS THE MOST REASONABLE AS MCS/MESOSCALE DYNAMICS WILL
DOMINATE REGARDLESS OF SUBTLE DIFFERENCES BETWEEN THE SYNOPTIC
TIMINGS.  UPPER LEVEL FLOW BECOMES INCREASINGLY DIVERGENT IN THE
NEXT FEW HOURS OVER CENTRAL TX AND EXPECT A SQUALL LINE TO DEVELOP
ALONG AN EAGLE PASS TO DFW LINE BY EARLY EVENING.  CORFIDI VECTORS
INDICATE THAT PROPAGATION OF ANY MCS WOULD BE SE WITH RELATIVELY
LIMITED FORWARD SPEED...AROUND 10-15KTS.  THIS WOULD INCREASE THE
THREAT OF HEAVY RAINFALL AS THE LOW LEVEL JET WILL PROVIDE GOOD
INFLOW OF DEEP TROPICAL MOISTURE.  THICKNESS VALUES ALSO ARE
DIVERGENT WHICH IS A HEAVY RAINFALL PLUS.  DUE TO RECENT RAINFALL
WITH SOME LOCALLY HIGHER AMOUNTS...A FLASH FLOOD WATCH OVER AT LEAST
THE EASTERN HALF OF THE CWA IS LIKELY A GOOD CALL.

ORGANIZED CONVECTION WILL LIKELY ENTER THE WESTERN CWA AFTER
MIDNIGHT AND MOVE EAST AND INTO THE GULF BY FRI AFTERNOON.  SLIGHT
POSSIBILITY STILL EXISTS THAT IF SQUALL LINE DOES NOT MAKE IT
THROUGH THE AREA...MOISTURE/INSTABILITY WILL LINGER INTO FRIDAY
NIGHT AND WILL CONTINUE TO CARRY LOW POPS.  HOWEVER NEXT SHIFT WILL
LIKELY BE ABLE TO DISCERN WHETHER THESE POPS CAN BE DROPPED
ALTOGETHER.  TEMPS WILL BE RAIN COOLED TONIGHT/FRIDAY AND WONT MAKE
DEVIATE FROM THE MAV/MET GUIDANCE.  CONVECTION FRI MORNING WILL GIVE
THE APPEARANCE OF A COLD FRONT BUT WILL FCST LIGHT NW WINDS THEN NE
BY FRI NIGHT BEFORE MAIN HIGH PRESSURE SURGE ARRIVES. SKIES SHOULD
CLEAR FROM W TO E LATE FRIDAY ALLOWING FOR SOME DECENT RADIATIONAL
COOLING AND FOG LATE FRI NIGHT.  ON THE MARINE SIDE...WILL HOLD ON
TO CHC OF RAIN THROUGH FRIDAY NIGHT AS FRONT WILL LIKELY STALL
OFFSHORE.  WILL NEED TO HOIST SCA OFFSHORE TONIGHT DUE TO 30KT LLJ
FEEDING INTO CONVECTION TO THE NORTH.

LONG-TERM (SAT THROUGH THU)...EXPECT THE SFC FRONT TO STALL ACROSS
THE COASTAL WATERS SAT...AS THE GFS/UKMET/NOGAPS LIFTS THE UPPER
SYSTEM AWAY TOWARD THE NE. THUS...CONVECTION TO CONTINUE OVR THE
WATERS AT LEAST THROUGH SAT NGT. PAST TWO RUNS OF THE GFS CONSISTENT
WITH ANOTHER UPPER SYSTEM MOVG ACRS THE CNTRL CONUS...RESULTING IN A
FROPA OVR THE CWFA BY SUN. CONCUR WITH THIS SOLN AND EXPECT PCPN TO
END OVR THE WATERS MON. WIND SPEEDS MAY APPROACH SCA CONDITIONS LATE
SUN-MON OVR THE COASTAL WATERS. THE MOST RECENT GFS PROGS YET
ANOTHER UPPER DISTURBANCE TO ENTER THE ROCKIES BY WED AND CONTRIBUTE
TO MSTR RTN BY THU...HWR GFS RUNS INCONSISTENT WITH RESPECT TO THIS
SOLN. UNSURE WHETHER MSTR WL BE SUFFICIENT TO GENERATE CONVECTION
TUE-THU AND WL RETAIN THE DRY FCST.

CRP TB 075/085 069/087 069 683
VCT TB 073/084 066/086 069 883
LRD TB 074/090 068/088 069 752

.CRP...SCA OFFSHORE ZONES TONIGHT.
       FLASH FLOOD WATCH 231>234-241-247 THROUGH 18Z FRI.

TR/92..SHOT-TERM
87...LONG-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