Severe Thunderstorm Warning 11, NWS Brownsville, TX

DEEP SOUTH TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
155 PM CDT WED APR 12 2000

EARLIER THIS MORNING AN OUTFLOW BOUNDARY MOVED OVER DEEP SOUTH TEXAS
INTO NORTHERN MEXICO.  THE BRO SOUNDING THIS MORNING INDCT A LIFTED
INDEX A -14.3 WHICH IS VERY UNSTABLE.  THE AIRMASS DESTABILIZED
SLIGHTLY DUE TO THE NORTHEAST WIND ALTHOUGH IT MIGHT BE MOVING NORTH
AND CAUSING THE AIRMASS TO BE UNSTABLE ONCE AGAIN.  A PVA IMPULSE IS
MOVING OVER DEEP SOUTH TEXAS THIS AFTERNOON CAUSING A LINE OF
THUNDERSTORMS MOVING OVER THE CENTRAL VALLEY AT THIS TIME.  ANOTHER
MAIN PVA AREA WILL BE MOVING OVER THE AREA TONIGHT AND THURSDAY
MORNING CAUSING ANOTHER CHANCE OF SHOWERS OR THUNDERSTORMS.  A DRIER
NORTHWEST FLOW WILL MOVE INTO THE AREA ON THURSDAY AFTERNOON CAUSING
THE SHOWERS TO END. TEMPERATURES WILL BE NEAR NORMAL FOR THIS TIME
AS CONDITIONS DRY BY THURSDAY AFTERNOON. WINDS WILL CONTINUE TO BE
FROM THE EAST TO NORTHEAST FAIRLY LIGHT.

A DRY AND STABLE AIRMASS WILL CONTINUE ON FRIDAY WITH A
NORTHWESTERLY FLOW ALOFT.  TEMPERATURES WILL WARM AND ABOVE NORMAL
WITH AMPLE AMOUNT OF SUNSHINE.  WINDS ON FRIDAY WILL SWITCH AROUND
FROM THE SOUTHEAST AT LIGHT TO MODERATE.

MARINE...SHOWERS AND THUNDERSTORMS WILL DOMINATE THE AREA THROUGH
THURSDAY MORNING WITH FAIRLY LIGHT WINDS EXCEPT ASSOCIATED WITH
THUNDERSTORMS.  WINDS WILL INCREASE AGAIN FROM THE SOUTHEAST ON
FRIDAY.

LONG TERM...A RELATIVELY DRY AND STABLE AIRMASS WILL DOMINATE THE
AREA THROUGH THE WEEKEND WITH ABOVE NORMAL TEMPERATURES.  HIGH
PRESSURE WILL RIDGE OVER SOUTHWEST TEXAS DURING THE WEEKEND CAUSING
VERY LITTLE CHANCE FOR RAIN.

55

BRO...NONE.

.BRO  66/81/66/85/68  40/40/00/00
.MFE  65/83/65/87/67  40/40/00/00
.RGD  62/85/62/90/65  40/40/00/00
.SPI  68/78/68/82/71  40/40/00/00

TXZ248>257-122300-

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1155 AM CDT WED APR 12 2000

...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS DEEP SOUTH
TEXAS THIS AFTERNOON AND TONIGHT...

AT MIDDAY...A COLD FRONT HAD DROPPED SOUTH...AND WAS DRAPED WEST TO
EAST ALONG THE RIO GRANDE RIVER. THIS FRONT HAS BEEN THE FOCUS FOR
SCATTERED THUNDERSTORMS ACROSS DEEP SOUTH TEXAS THIS MORNING. MOST
OF THE ACTIVITY HAS BEEN CONCENTRATED OVER THE WESTERN AREAS...
WHERE OVER AN INCH OF RAIN HAD ACCUMULATED OVER PARTS OF ZAPATA AND
WESTERN STARR COUNTIES.

AN UPPER LEVEL DISTURBANCE OVER MEXICO IS EXPECTED TO AFFECT DEEP
SOUTH TEXAS THIS AFTERNOON...ADDING ANOTHER TRIGGER TO THE ALREADY
UNSTABLE AND MOIST ATMOSPHERE IN PLACE. THE POTENTIAL FOR THUNDERSTORMS
WITH SOME POSSIBLY SEVERE...EXISTS ACROSS DEEP SOUTH TEXAS THIS
AFTERNOON. HEAVY RAINS...LARGE HAIL AND STRONG GUSTY WINDS WILL BE
THE MAIN THREATS.

IN ADDITION...YET ANOTHER UPPER LEVEL DISTURBANCE IS EXPECTED TO
CROSS THE AREA LATER TONIGHT AND EARLY THURSDAY MORNING. THIS COULD
SET THE STAGE FOR MORE THUNDERSTORM DEVELOPMENT OVERNIGHT.

THE NATIONAL WEATHER SERVICE IN BROWNSVILLE WILL CLOSELY MONITOR THE
DEVELOPING WEATHER SITUATION...AND WILL ISSUE STATEMENTS...ADVISORIES...
AND WARNINGS AS NEEDED. NO WATCHES OR WARNINGS ARE IN EFFECT FOR DEEP
SOUTH TEXAS AT THE MOMENT.

ALL RESIDENTS OF DEEP SOUTH TEXAS SHOULD KEEP UPDATED ON THE WEATHER
TODAY. STAY TUNED TO LOCAL RADIO...TV...OR NOAA WEATHER RADIO FOR
THE LATEST WEATHER INFORMATION.

TXZ253>257-122000-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
200 PM CDT WED APR 12 2000

...STRONG THUNDERSTORMS MOVING INTO HIDALGO...CAMERON AND WILLACY
COUNTIES...

A LINE OF STRONG THUNDERSTORMS CONTINUES TO MOVE SOUTHEAST ACROSS
DEEP SOUTH TEXAS...AS INDIVIDUAL STORMS MOVE TO THE NORTHEAST
AT ABOUT 20 MILES AN HOUR.  RADAR INDICATED THE STRONGER STORMS
WERE LOCATED NEAR MCALLEN AND SOUTHWEST OF BROWNSVILLBE.  THESE
STORMS WILL LIKELY PRODUCE HEAVY DOWNPOURS...CAUSING SOME LOCALIZED
FLOODING. SOME HAIL MAY ACCOMPANY THESE STORMS. THESE STORMS
MAY INTENSIFY AND REQUIRE A SEVERE THUNDERSTORM WARNING LATER THIS
AFTERNOON.

WATKINS