Severe Thunderstorm Warning 27, NWS Brownsville, TX

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
850 PM CDT TUE APR 29 2003

SHORT TERM...HAVE TWO MAIN AREAS OF CONCERN FOR CONV NEAR THE BRO
CWA.  TWO AREAS OF CONV HAVE FIRED UP OVER THE HIGHER TERRAIN OF
MEXICO FROM THE UVV INDUCED BY THE AFTERNOON HEATING.  THE FIRST IS
LOCATED ABOUT 30 NM SOUTH OF RIO GRANDE CITY MOVING SOUTHEAST AT 25
T0 30 MPH.  THIS ISOLATED INTENSE CELL IS FIRING IN HIGHER CAPE
VALUES OF 4000 TO 4800 J/KG MAINLY CONCENTRATED OVER NE MEX.  LAPS
CAPE VALUES SHOW THAT THIS CELL WILL MOVE INTO MORE STABLE AIR AS IT
GETS CLOSER TO THE S TX/N MEX COASTLINE WHERE CAPES OF 2000 TO 3400
PREVAIL.  WITH THIS CURRENT SPEED AND MOVEMENT...THIS CELL WILL
LIKELY REMAIN SOUTH OF BORDER BEFORE FINALLY DISSIPATING WITH THE
LOSS OF THE DIURNAL HEATING.

THE 2ND AREA LOCATED ALONG THE U.S./MEXICO BORDER OVER WEBB AND
DIMMITT COUNTIES MAY HAVE MORE OF AN IMPACT ON THE BRO CWA.  HERE IS
THE LATEST MESOSCALE DISC FROM SPC CONCERNING THIS AREA.

MEXICAN MCS CONTINUES TO HEAD SEWD TOWARDS AREAS IN SOUTH TEXAS. A
WW MAY BE REQUIRED OVER THE NEXT HOUR OR SO.

RECENT COMPOSITE IR/RADAR IMAGERY INDICATES MCS TYPE STRUCTURE
HEADING SEWD ACROSS THE NRN PARTS OF THE NUEVO LEON PROVINCE IN NRN
MEXICO. AN INSPECTION OF MODEL WIND FIELDS INDICATES 70-80 KTS OF
UPPER LVL FLOW OVER THE REGION WITH 5-10 KTS OF ESELY LOW-LVL FLOW.
TRACKING FEATURE OF THE NRN MEXICAN FEATURE INDICATES MOVEMENT AT
AROUND 27 KTS FROM 295 DEGREES WHICH SHOULD MOVE INTO SWRN WEBB
COUNTY BETWEEN 30/02-02330Z. ALTHOUGH DOWNSTREAM 30/00Z RAOBS AT
BOTH CRP AND BRO INDICATE DISTINCT CAPPING...50MB MLCAPE VALUES OF
3000-4000 J/KG...STEEP MID-LVL LAPSE RATES...AND 15-20 KTS OF SR
INFLOW WILL LIKELY LEAD TO INCREASING BOW ECHO DEVELOPMENT OVER THE
NEXT HOUR OR SO. MAIN THREAT WILL BE STRONG DAMAGING WINDS.

IF THIS MCS CONTINUES ITS CURRENT SPEED AND MOVEMENT...THE NORTHERN
TIER OF COUNTIES OF ZAPATA...JIM HOGG...BROOKS AND KENEDY MAY NEED
TO BE UPDATED FOR INCREASE OVERNIGHT POPS AND POSSIBLE WW.

MARINE...THE ONSHORE FLOW WILL CONTINUE ALONG THE LOWER TX COASTLINE
THROUGH THE NIGHT.  BUOY020 REPORTS A SE FLOW FROM 10 TO 15 KTS WITH
SWELLS NEAR 4 FT.  WILL UPDATE THE CWF TO INCREASE SWELLS OFFSHORE A
BIT.  OTHERWISE...THE REST OF THE CURRENT CWF LOOKS OK.

AVIATION...THE LOW LEVEL E-SE FLOW COMING IN OFF OF THE GULF OF MEX
WILL KEEP CIGS AT OR BELOW 1 KFT AT THE BRO AND HRL AIRPORTS.
DEBRIS CLD COVER FROM THE WESTERN CONV WILL KEEP A LITTLE BETTER
CIGS IN PLACE AT MFE...BUT BELIEVE THAT CIGS AT THE MFE AIRPORT WILL
EVENTUALLY DEGRADE AS THE OVERNIGHT CAPPING BECOMES ESTABLISHED OVER
THE REGION.

.BRO...NONE.

SYNOPTIC-AVIATION-MARINE...60/MESO...CAMPBELL

THIS PRODUCT IS ALSO AVAILABLE ON OUR INTERNET WEB PAGE AT:
HTTP://WWW.SRH.NOAA.GOV/BRO

TXZ248>257-300900-

HAZARDOUS WEATHER OUTLOOK...UPDATED FOR DAY ONE WORDING
NATIONAL WEATHER SERVICE BROWNSVILLE TX
920 PM CDT TUE APR 29 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS.

.DAY ONE...TONIGHT.

A CLUSTER OF STRONG THUNDERSTORMS WHICH FORMED OVER NORTHEAST MEXICO
EARLIER THIS EVENING IS MOVING TOWARDS LAREDO IN WEBB COUNTY. THIS
CLUSTER OF THUNDERSTORMS MAY MOVE OVER THE NORTHERN PORTIONS OF
ZAPATA...JIM HOGG...BROOKS AND KENEDY COUNTIES THROUGH 2 AM WEDNESDAY
MORNING.  AN ISOLATED SEVERE THUNDERSTORM IS POSSIBLE OVER THESE
COUNTIES THROUGH 2 AM WEDNESDAY MORNING.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

NO HAZARDOUS WEATHER IS EXPECTED.

.SPOTTER INFORMATION STATEMENT.

SPOTTER ACTIVATION MAY BE REQUIRED ACROSS ZAPATA...JIM HOGG...BROOKS
AND KENEDY COUNTIES THROUGH 2 AM WEDNESDAY MORNING.

SPEECE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1054 PM CDT TUE APR 29 2003

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1053 PM    ZAPATA                    TX   0.75 IN HAIL
04/29/03   ZAPATA

TRS