Severe Thunderstorm Warning 54, NWS Brownsville, TX

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1020 AM CDT SUN JUL 1 2001

THIS MORNINGS SOUNDING REVEALED AN UNCAPPED ATMOSPHERE WITH SLIGHTLY
STEEPER MID LEVEL LAPSE RATES (-7 C/KM) WITH HIGH CAPE (5486 J/KG)
AND LOW LIFTED INDEX (-11). PRECIPITABLE WATER VALUE LINGERS AROUND
1.70 INCHES. HOWEVER...THERE IS A CAVEAT WITH LACK OF MID LEVEL
SHORT WAVE TRIGGER.  AMPLE CONVECTION HAS FIRE OFF ALONG THE
MID/UPPER LEVEL TROF OVER THE COASTAL BEND INTO CENTRAL TEXAS.
CURRENT CONVECTION OVER THE COASTAL BEND WILL CONTINUE TO DECREASE
SLIGHTLY THIS LATE MORNING AND EARLY AFTERNOON AS IT IS THE MOST
STABLE PART OF THE DAY.  HOWEVER...WITH PEAK DAYTIME HEATING AND
PLENTY OF SOLAR RADIATION...WITH LACK OF CIRRUS SHIELD OVER THE MID
AND UPPER VALLEY...SHWRS AND TSTMS SHOULD INCREASE OVER THE CENTRAL
PORTION OF THE CWA BY MID TO LATE AFTN WITH FAR WEST SECTIONS SEEING
SOME ACTIVITY LATE THIS AFTERNOON INTO THE EVENING HOURS. OUTFLOW
OVER JIM WELLS COUNTY AND EAST DUVAL COUNTY HAVE IGNITED ADDITIONAL
ISOLATED TSTMS THIS MORNING. MID LVL STEERING WINDS MAY ALLOW SOME
OF THIS CONVECTION TO MOVE SOUTH-SOUTHWEST INTO BROOKS AND JIM HOGG
COUNTIES BY LATE MORNING. A LOT DEPENDS ON FURTHER OUTFLOW BOUNDARIES
UPSTREAM. WILL LET CURRENT FCST RIDE.

.MARINE...THE GRADIENT WILL RELAX THIS AFTERNOON WITH A MODERATE
ONSHORE FLOW THIS MORNING BECOMING WEAKER AS THE DAY PROGRESSES.
THE COMBINATION OF A WEAK SFC HIGH OVER SOUTH TEXAS AND WESTERN
GULF AND LOW PRESS OVER THE CENTRAL GULF WILL BACK WINDS TO A
EAST-SOUTHEAST DIRECTION BY LATE AFTERNOON AND TONIGHT. BUT SOME
THUNDERSTORMS WILL PRODUCE LOCALLY STRONGER WINDS AND HIGHER SEAS.

SYNOPTIC-PUBLIC/AVIATION-MARINE...CORDERO (64)
MESO...WATKINS

INTERNET ADDRESS...WWW.SRH.NOAA.GOV/BRO

.BRO...NONE.

TXZ248>257-011715-

SPECIAL WEATHER STATEMENT
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
910 AM CDT SUN JUL 1 2001

...A POTENTIAL FOR A FEW SEVERE THUNDERSTORMS
   AND LOCALLY HEAVY RAINFALL THIS AFTERNOON...

CURRENT SATELLITE IMAGERY INDICATED NUMEROUS SHOWERS AND
THUNDERSTORMS HAD DEVELOPED ALONG AN UPPER LEVEL TROUGH
THIS MORNING FROM THE SOUTHERN PORTION OF THE COASTAL BEND
EXTENDING NORTHWARD INTO CENTRAL TEXAS.

THE COMBINATION OF HIGH PRESSURE ALOFT OVER THE FOUR CORNERS AREA
AND A TROUGH OF LOW PRESSURE ALONG THE COAST WILL ALLOW MID LEVEL
WINDS OF THE ATMOSPHERE TO STEER THESE STORMS SOUTHWARD INTO THE VERY
MOIST AND UNSTABLE ATMOSPHERE OF DEEP SOUTH TEXAS THIS AFTERNOON.

A FEW OF THE THUNDERSTORMS THIS AFTERNOON MAY PRODUCE WINDS
AROUND 50 MPH...HEAVY RAIN...HAIL...AND DANGEROUS CLOUD-TO-GROUND
LIGHTNING OVER PORTIONS OF DEEP SOUTH TEXAS.

RESIDENTS OF DEEP SOUTH TEXAS CAN EXPECT LOCALIZED TOTAL RAINFALL
AMOUNTS RANGING BETWEEN 1 AND 3 INCHES WHICH MAY RESULT IN RAPID
PONDING OF WATER ON SOME AREA ROADWAYS AND LOW LYING AREAS.

REMEMBER TO SEEK HIGHER GROUND IMMEDIATELY IF FLOODING IS OBSERVED OR
IF A WARNING IS ISSUED. NEVER DRIVE INTO WATER OF UNKNOWN DEPTH.

STAY TUNED TO THE NATIONAL WEATHER SERVICE FOR THE LATEST WEATHER
INFORMATION.

FOR THE LATEST WEATHER FORECASTS AND WARNINGS...CHECK OUR WEB SITE AT
HTTP://WWW.SRH.NOAA.GOV/BRO

CORDERO