Severe Thunderstorm Warning 57, NWS Brownsville, TX

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
339 PM CDT WED AUG 13 2003

.DISCUSSION...SCT CONVECTION THIS PM BY TWO DIFFERENT MECHANICS.
MEAN MOTION OF STORMS OVER RGV IS EAST...ADJ MEX WEST. PRESSURE
RISES OFFSHORE...WITH PRESSURE FALLS OVER INLAND AREAS. ALL IN
PREPARATION FOR THE EXODUS OF OUR UPPER LOW TO THE TX BIG BEND AND
THE INTRODUCTION OF DEEP AND WET SOUTHERLY FLOW. THIS WILL BE
FOLLOWED FRIDAY BY TROPICAL ENERGY RAPIDLY APPROACHING FROM THE
EAST.

HAVE STAYED CLOSE TO LATEST AVN RUN INIT THRU 120H. HONED TEMPS DOWN
TO RESPOND TO HVY RAFL SCENARIO. ISSUED SPS FOR PENDING RAINS AND
APPROACHING TROPICAL WAVE...WITH THE POSSIBILITY OF FLASH FLOOD
WATCH BEING ISSUED DURING THE EARLY MRNG HOURS THU.

MARINE...AT 2 PM BUOY020 REPORTED NORTH WINDS AT 10KNOTS WITH SEAS 2
FEET.  A MID LEVEL TROUGH OFF THE COAST WILL MOVE INLAND OVERNIGHT
INTO TOMORROW.  THIS WILL CAUSE WIDESPREAD RAINS ACROSS THE ADJACENT
COASTAL WATERS AS IT MOVES WEST INTO MEXICO.  THIS WILL CONTINUE
INTO THURSDAY BEFORE A BRIEF BREAK ON THURSDAY.  OVER THE WEEKEND A
TROPICAL SYSTEM MOVING WESTWARD ACROSS FLORIDA WILL MOVE INTO THE
WESTERN GULF COASTAL WATERS INCREASING WINDS AND SEAS TO ADVISORY
LEVELS.

AVIATION...VFR CONDS WILL DEGRADE WITH TIME...AS NUMEROUS TSTMS WITH
HVY RAFL BEGIN TO DEVELOP EARLY THU MRNG. IFR CIGS AND VSBYS CAN BE
XPCTD OVR MOST OF THE LOWER RIO GRANDE VLY DURING THU AND THU NGT.
EXPECT WX TO CONTINUE TO DEGENERATE FRI AND THRU THE WEEKEND...AS A
TROPICAL DISTURBANCE APPROACHES FROM THE EAST...ACCOMPANIED BY
STRONG TSTMS WITH HVY RAFL AND STRONG/GUSTY WINDS.

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL ET 077/091 077/091 077 50/70/50/60/60
BROWNSVILLE         ET 077/091 077/091 077 50/70/50/60/60
HARLINGEN           ET 075/092 075/092 075 50/70/50/60/60
MCALLEN             ET 075/093 075/093 075 50/70/50/60/60
RIO GRANDE CITY     ET 074/090 074/090 074 50/90/70/60/60
SOUTH PADRE ISLAND  ET 079/086 078/087 078 50/70/50/60/60

.BRO WATCHES/WARNINGS/ADVISORIES...NONE.

58/64

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

TXZ248>257-141100-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
600 AM CDT WED AUG 13 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS.

.DAY ONE...TODAY AND TONIGHT.

A MOIST AND UNSTABLE ATMOSPHERE...IN COMBINATION WITH AN UPPER LEVEL
TROUGH OF LOW PRESSURE WILL GENERATE SCATTERED SHOWERS AND
THUNDERSTORMS THROUGH TONIGHT. SOME OF THESE STORMS MAY BE
SEVERE...PRODUCING WIND GUSTS IN EXCESS OF 60 MPH...HEAVY
RAIN...FLOODING OF ROADWAYS...FREQUENT LIGHTNING AND HAIL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

SCATTERED SHOWERS AND THUNDERSTORMS WILL TAPER TO ISOLATED COVERAGE
FRIDAY AS THE UPPER LEVEL TROUGH MOVES FARTHER WEST INTO
NORTHWESTERN MEXICO AND UPPER LEVEL HIGH PRESSURE BUILDS IN FROM THE
WESTERN GULF.

.SPOTTER INFORMATION STATEMENT.

SPOTTERS AND EMERGENCY MANAGERS ARE ASKED TO MONITOR WEATHER
CONDITIONS CLOSELY TODAY AND TONIGHT.

GMZ130-150-155-170-175-TXZ248>257-140300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1205 PM CDT WED AUG 13 2003

...ATMOSPHERIC CONDITIONS WILL CONTINUE TO ALLOW THE
FORMATION OF THUNDERSTORMS WITH HEAVY RAINS FOR THE NEXT SEVERAL
DAYS...

AN UPPER LEVEL DISTURBANCE IS CURRENTLY MOVING JUST NORTH OF
THE RIO GRANDE VALLEY...AND WILL BE CENTERED OVER THE TEXAS
BIG BEND BY THURSDAY. COPIOUS MOISTURE...AMPLE LIFT AND A
CONSISTENT UNSTABLE ATMOSPHERE WILL ENCOURAGE THUNDERSTORM
DEVELOPMENT IN THE RIO GRANDE VALLEY NOW THROUGH THE WEEKEND.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HEAVY RAINS
WILL DEVELOP THIS AFTERNOON...AND INCREASE IN AREAL COVERAGE AND
INTENSITY THURSDAY. A FLASH FLOOD WATCH MAY BE ISSUED LATER
TONIGHT FOR ALL OF THE RIO GRANDE VALLEY ON THURSDAY...AND
POSSIBLY BEYOND.

YESTERDAY...DEEP SOUTH TEXAS RECEIVED 3 TO 5 INCHES OF RAINFALL OVER
AREAS OF ZAPATA AND STARR COUNTIES...AND PORTIONS OF SOUTH-CENTRAL
CAMERON COUNTY. BROWNSVILLE IS CURRENTLY 5 INCHES OF RAINFALL BELOW
NORMAL FOR THE YEAR...AND THESE HEAVY RAINS SHOULD BRING
RELIEF TO A DRY AND HOT DEEP SOUTH TEXAS.

THE UPPER LEVEL DISTURBANCE OVER THE TEXAS BIG BEND IS NOT THE
ONLY PLAYER IN THIS HEAVY RAIN EVENT...AS A TROPICAL WAVE IS
FORECAST TO MOVE QUICKLY WEST FROM THE FLORIDA STRAITS FRIDAY...
INDUCING HEAVY RAINS IN THE RIO GRANDE VALLEY BY LATE FRIDAY
THROUGH LATE SATURDAY.

ALTHOUGH RAINS ARE NEEDED IN ALL OF THE RIO GRANDE VALLEY...
FLOODING IS A REAL HAZARD THAT MUST BE ANTICIPATED DURING THE NEXT
FEW DAYS. REMEMBER TO DRIVE ACCORDING TO WEATHER CONDITIONS AND
VISIBILITIES...AS HEAVY RAINS CAN REDUCE VISIBILITIES TO NEAR ZERO IN
A SHORT PERIOD OF TIME. ROADWAY PONDING AND FLOODING OF LOW-LYING
AREAS CAN QUICKLY JERK A CAR OFF THE ROAD...OR INTO ON-COMING
TRAFFIC. NEVER DRIVE YOUR VEHICLE INTO WATERS OF UNKNOWN DEPTH AND
REMEMBER OUR NEW LIFE-SAVING SLOGAN HERE AT THE NATIONAL WEATHER
SERVICE...TURN AROUND...DONT DROWN.

AS ALWAYS...CONTINUE TO MONITOR NOAA WEATHER RADIO...COMMERCIAL
RADIO AND TELEVISION...OR YOUR LOCAL CABLE OUTLET...FOR THE
LATEST WEATHER INFORMATION. PHILO

PHILO

TXZ248>257-140300-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1205 PM CDT WED AUG 13 2003

...ATMOSPHERIC CONDITIONS WILL CONTINUE TO ALLOW THE
FORMATION OF THUNDERSTORMS WITH HEAVY RAINS FOR THE NEXT SEVERAL
DAYS...

AN UPPER LEVEL DISTURBANCE IS CURRENTLY MOVING JUST NORTH OF
THE RIO GRANDE VALLEY...AND WILL BE CENTERED OVER THE TEXAS
BIG BEND BY THURSDAY. COPIOUS MOISTURE...AMPLE LIFT AND A
CONSISTENT UNSTABLE ATMOSPHERE WILL ENCOURAGE THUNDERSTORM
DEVELOPMENT IN THE RIO GRANDE VALLEY NOW THROUGH THE WEEKEND.
SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WITH HEAVY RAINS
WILL DEVELOP THIS AFTERNOON...AND INCREASE IN AREAL COVERAGE AND
INTENSITY THURSDAY. A FLASH FLOOD WATCH MAY BE ISSUED LATER
TONIGHT FOR ALL OF THE RIO GRANDE VALLEY ON THURSDAY...AND
POSSIBLY BEYOND.

YESTERDAY...DEEP SOUTH TEXAS RECEIVED 3 TO 5 INCHES OF RAINFALL OVER
AREAS OF ZAPATA AND STARR COUNTIES...AND PORTIONS OF SOUTH-CENTRAL
CAMERON COUNTY. BROWNSVILLE IS CURRENTLY 5 INCHES OF RAINFALL BELOW
NORMAL FOR THE YEAR...AND THESE HEAVY RAINS SHOULD BRING
RELIEF TO A DRY AND HOT DEEP SOUTH TEXAS.

THE UPPER LEVEL DISTURBANCE OVER THE TEXAS BIG BEND IS NOT THE
ONLY PLAYER IN THIS HEAVY RAIN EVENT...AS A TROPICAL WAVE IS
FORECAST TO MOVE QUICKLY WEST FROM THE FLORIDA STRAITS FRIDAY...
INDUCING HEAVY RAINS IN THE RIO GRANDE VALLEY BY LATE FRIDAY
THROUGH LATE SATURDAY.

ALTHOUGH RAINS ARE NEEDED IN ALL OF THE RIO GRANDE VALLEY...
FLOODING IS A REAL HAZARD THAT MUST BE ANTICIPATED DURING THE NEXT
FEW DAYS. REMEMBER TO DRIVE ACCORDING TO WEATHER CONDITIONS AND
VISIBILITIES...AS HEAVY RAINS CAN REDUCE VISIBILITIES TO NEAR ZERO IN
A SHORT PERIOD OF TIME. ROADWAY PONDING AND FLOODING OF LOW-LYING
AREAS CAN QUICKLY JERK A CAR OFF THE ROAD...OR INTO ON-COMING
TRAFFIC. NEVER DRIVE YOUR VEHICLE INTO WATERS OF UNKNOWN DEPTH AND
REMEMBER OUR NEW LIFE-SAVING SLOGAN HERE AT THE NATIONAL WEATHER
SERVICE...TURN AROUND...DONT DROWN.

AS ALWAYS...CONTINUE TO MONITOR NOAA WEATHER RADIO...COMMERCIAL
RADIO AND TELEVISION...OR YOUR LOCAL CABLE OUTLET...FOR THE
LATEST WEATHER INFORMATION. PHILO

PHILO