Flash Flood Warning 4, NWS Brownsville, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
845 PM CDT THU MAY 15 2008

.DISCUSSION...THE PATTERN OF THE LAST 24 HOURS CONTINUES WITH
SUBTROPICAL MOISTURE MOVING UP FROM THE SOUTHWEST AND INSTABILITY
ALOFT TRIGGERING STORMS OVER THE MEXICAN PLATEAU WHICH THEN MOVE
NORTHEAST. LOW LEVEL MOISTURE FEEDS INTO THE LOWER LEVELS AND STRONG
UPDRAFTS PRODUCE HAIL IN THE ATMOSPHERE ALOFT. THE LATEST BRO
SOUNDING SHOWS 2 PLUS INCHES OF PWAT AND NO CAP NEAR BRO. STRONG
CELLS ARE NOTED ON RADAR SOUTH OF THE RIVER...BUT THEIR NORTHWARD
PROGRESS HAS SLOWED SOMEWHAT OVER RECENT SCANS.

THE ONGOING CONVECTIVE ACTIVITY SHOULD SLOWLY INCREASE IN COVERAGE
TONIGHT AS A COLD FRONT APPROACHES. ISOLATED STRONGER STORMS MAY
BECOME SEVERE WITH THE MAIN THREAT BEING DAMAGING WINDS AND HAIL.
THE MODELS HAVE ALSO BEEN SUGGESTING LOCALIZED HEAVY RAIN...WHICH
APPEARS POSSIBLE AS STORMS DEVELOP AND MOVE REPEATEDLY OVER THE SAME
AREA...THOUGH HISTORY HAS NOT YIELDED SIGNIFICANT REPORTS OF HEAVY
RAIN. THE LATEST CONVECTIVE OUTLOOK PLACES MUCH OF DEEP SOUTH TEXAS
BACK INTO SLIGHT RISK AREA. A LINE OF THUNDERSTORMS FORMED UP TO THE
NORTHWEST NEAR EAGLE PASS AND IS MOVING SOUTHEAST. THE LINE WILL
LIKELY INTERACT WITH THE FRONTAL BOUNDARY TO PRODUCE STRONG STORMS
OVER THE RIO GRANDE PLAINS...AND THESE COULD ALSO MOVE SOUTH INTO
DEEP SOUTH TEXAS. ALL-IN-ALL IT IS A COMPLEX SITUATION TONIGHT THAT
WILL CONTINUE TO EVOLVE OVER THE NEXT SEVERAL HOURS.
&&

.PREV DISCUSSION...ISSUED AT 145 PM CDT THU MAY 15 2008...A WEAK
COLD FRONT FROM NORTHERN CONTINUES TO MOVE SOUTH AND SHOULD MOVE
THROUGH DEEP SOUTH TEXAS BY FRIDAY MORNING. CHANCES FOR SHOWERS OR
THUNDERSTORMS SHOULD BE THE HIGHEST FRIDAY MORNING AS THE FRONT
MOVES THROUGH AND CHANCES SHOULD DECREASE SLIGHTLY BY THE WEEKEND.
TEMPERATURES WILL BE SLIGHTLY BELOW NORMAL FOR THIS TIME OF YEAR DUE
TO THE CLOUD COVER AND COOLER NORTHEAST WINDS. WINDS WILL BE EAST TO
SOUTHEAST TONIGHT BECOMING LIGHT TO MODERATE FROM THE NORTHEAST BY
FRIDAY AFTERNOON. BRO SOUNDING THIS MORNING SHOWED A PRECIP WATER OF
1.55 AND A K-INDEX OF 27. THE BOUNDARY LAYER RELATIVE HUMIDITIES
SHOWED GREATER THAN 60 PERCENT ALL THE WAY UP TO 500 MB UNTIL SUNDAY
NIGHT. DRIER AND SLIGHTLY WARMER AIR WILL BE THE RULE BY MONDAY OF
NEXT WEEK AS A DRY NORTHWEST WINDS ALOFT WILL DOMINATE.
&&

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

54/61/69

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WWW.WEATHER.GOV/BROWNSVILLE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
528 AM CDT THU MAY 15 2008

GMZ130-132-135-150-155-170-175-TXZ248>257-161200-
LAGUNA MADRE FROM THE PORT OF BROWNSVILLE TO THE ARROYO COLORADO-
LAGUNA MADRE FROM THE ARROYO COLORADO TO 5 NM NORTH OF PORT
MANSFIELD TX-
LAGUNA MADRE FROM 5 NM NORTH OF PORT MANSFIELD TO BAFFIN BAY TX-
COASTAL WATERS FROM PORT MANSFIELD TO THE RIO GRANDE OUT 20 NM-
COASTAL WATERS FROM BAFFIN BAY TO PORT MANSFIELD OUT 20 NM-
WATERS FROM PORT MANSFIELD TO THE RIO GRANDE EXTENDING FROM 20 TO
60 NM-
WATERS FROM BAFFIN BAY TO PORT MANSFIELD EXTENDING FROM 20 TO
60 NM-ZAPATA-JIM HOGG-BROOKS-KENEDY-STARR-HIDALGO-INLAND WILLACY-
INLAND CAMERON-COASTAL WILLACY-COASTAL CAMERON-
528 AM CDT THU MAY 15 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS...THE GULF
OF MEXICO AND THE LAGUNA MADRE.

.DAY ONE...TODAY AND TONIGHT.

ISOLATED STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE OVERNIGHT
TONIGHT AS A COLD FRONT MOVES THROUGH THE REGION. THE MAIN THREAT
FROM THESE THUNDERSTORMS WOULD BE LARGE HAIL.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

A LATE SEASON COLD FRONT WILL MOVE THROUGH THE REGION FRIDAY
MORNING. SHOWERS AND THUNDERSTORMS ARE EXPECTED ALONG THIS COLD
FRONT. SOME THUNDERSTORMS COULD BE STRONG TO SEVERE WITH THE
THREAT FOR LARGE HAIL. WINDS BEHIND THE FRONT WILL REACH 20 KNOTS
ACROSS THE GULF OF MEXICO.  SMALL CRAFT ADVISORIES ARE EXPECTED.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED OVERNIGHT TONIGHT INTO FRIDAY
MORNING.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1220 AM CDT FRI MAY 16 2008

TXZ248-160630-
ZAPATA-
INCLUDING THE CITY OF...ZAPATA
1220 AM CDT FRI MAY 16 2008

STRONG THUNDERSTORMS ARE DEVELOP OVER ZAPATA COUNTY AS WELL AS
NORTHWEST TAMAULIPAS JUST WEST OF THE TOWN OF FALCON. THE STORMS
ARE MOVING EAST TO NORTHEAST AT AROUND 15 MPH. THE STORMS COULD
PRODUCE MARBLE SIZE HAIL...GUSTY WINDS TO 50 MPH AND VERY HEAVY
RAIN WITH AMOUNTS UP TO ONE INCH IN LESS THAN ONE HOUR.

GB