Severe Thunderstorm Warning 18, NWS Brownsville, TX

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
330 AM CDT TUE MAY 2 2000

CONVERGENCE PARTICULARLY STRONG OVER THE NORTHEAST PORTION OF THE
THE FORECAST AREA. MERGING CELLS APPARENT ON SATELLITE AND DOPPLER
RADAR. LINE OF CONVERGENCE WILL WORK ITS WAY SOUTH AND EAST PER
ETA MODEL. ETA IS DOING EXCELLENT JOB PICKING UP ON MAIN SYNOPTIC
FEATURES AND DISTURBANCES. THUS...WILL USE THIS MODEL FOR THE
FORECAST.

ETA CROSS SECTIONS/TIME HEIGHTS SHOW BEST VERTICAL MOTION AND DYNAMICS
MOVING SOUTH AND EAST INTO THE LOWER VALLEY @ 12Z.  FOCUSING WILL
PRIMARILY BE FOCUSED OVER THE EASTERN CWA THIS MORNING...WITH ETA
SHOWING ADDITIONAL DISTURBANCES MOVING IN FROM THE NORTHWEST LATE
AFTERNOON AND EVENING. SO THERE MAY BE A VERY SHORT BREAK IN THE
ACTION ACROSS THE VALLEY DURING THE MID AFTERNOON. WEAKER
PERTURBATIONS WILL CONTINUE TO MOVE THROUGH THE BASE OF TROF THROUGH
EARLY MORNING WEDNESDAY.  UPSTREAM RIDGING OVER THE INTER-MOUNTAIN
WEST WILL PUSH UPPER TROF TO THE EAST INTO LOUISIANA. SUBSIDENT FLOW
WILL MOVE INTO THE AREA AS THE DAY PROGRESSES WED WITH NWLY ALOFT
BUILDING INTO THE AREA. MEAN 1000-500MB RH'S SHIFT EASTWARD WITH THE
LOW.

IN THE EXTENDED...UPPER LOW IN A DEBILITATED MANNER WILL REMAIN
PRETTY STATIONARY OVER THE NORTHERN TEXAS GULF COAST AND LOUISIANA
THROUGH THE PERIOD.  RETURN FLOW WILL ONCE AGAIN SET UP WITH SFC
HIGH OVER THE MID-ATLANTIC STATES. BOUNDARY LAYER WILL MOISTEN
AS STRONGER RETURN FLOW SETS UP BY SATURDAY.

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

SYNOPTIC...CORDERO (64) / SPEECE (60)
MESO...SW (56)
HMT...MARTINEZ

BRO TB 085/070 084/070 087 64632
MFE TB 086/071 087/070 089 64632
RGC TB 088/066 089/067 092 64632
SPI TB 082/075 082/076 085 64632

.BRO...SVR THUNDERSTORM WATCH FOR KENEDY AND BROOKS COUNTIES
       (TXZ250-251) THROUGH 7 AM (12Z).

TXZ248>257-021600-

DEEP SOUTH TEXAS THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1148 PM CDT MON MAY 1 2000

THE NATIONAL WEATHER SERVICE IS MONITORING A POTENT UPPER LEVEL
STORM SYSTEM...MOVING ACROSS NORTH CENTRAL TEXAS. THIS SYSTEM WILL
AGAIN INCREASE THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS OVER DEEP
SOUTH TEXAS.  ANOTHER ROUND OF STORMS IS EXPECTED TO DEVELOP A FEW
HOURS BEFORE DAYBREAK THROUGH THE EARLY AFTERNOON HOURS TODAY...
AS THE UPPER LEVEL STORM SYSTEM TRACKS SOUTHWARD OVER THE LONE STAR
STATE.  ALTHOUGH THE MAIN THREAT WILL BE HEAVY RAIN...A FEW
THUNDERSTORMS MAY REACH SEVERE LIMITS WITH STRONG WINDS...HAIL AND
CONCEIVABLY ISOLATED TORNADOES.

SEVERE THUNDERSTORMS DID OCCUR OVER THE WEST-CENTRAL PART OF THE RIO
GRANDE VALLEY MONDAY EVENING. ALSO...A NORTH TO SOUTH SWATH OF 1 TO
2 INCHES OF RAINFALL FELL. THIS SWATH EXTENDED FROM RIO GRANDE CITY
TO LA GLORIA TO THE WESTERN PART OF BROOKS COUNTY. A RIO GRANDE CITY
WEATHER OBSERVER REPORTED 1.10 INCHES OF RAINFALL. IN ADDITION...A
FUNNEL CLOUD WAS REPORTED SOUTH OF LA GLORIA BY THE STARR COUNTY
SHERIFF MONDAY EVENING.

SPOTTER GROUPS AND EMERGENCY MANAGEMENT PERSONNEL IN DEEP SOUTH
TEXAS SHOULD BE ON THE ALERT FOR THE RE-DEVELOPMENT OF OMINOUS
WEATHER CONDITIONS. ALL RESIDENTS OF DEEP SOUTH TEXAS SHOULD KEEP
UPDATED ON THE WEATHER TUESDAY THROUGH LOCAL RADIO...TELEVISION...OR
CABLE SOURCES...AND NOAA WEATHER RADIO.

CORDERO