Severe Thunderstorm Warning 16, NWS Brownsville, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
731 PM CDT MON APR 30 2007

.DISCUSSION...A TORNADO WATCH REMAINS IN EFFECT FOR AREAS JUST NORTH
OF THE RIO GRANDE VALLEY UNTIL 10 PM. SEVERE TORNADIC THUNDERSTORMS
HAVE PERSISTED IN NORTHERN AND CENTRAL DUVAL COUNTY EARLY THIS
EVENING...AND THESE DANGEROUS THUNDERSTORMS HAVE BEEN DRIFTING
SLOWLY SOUTH TOWARD NORTHERN JIM HOGG AND ZAPATA COUNTIES. THE
ATMOSPHERE REMAINS VERY SUPPORTIVE FOR THE PERSISTENCE OF THESE
THUNDERSTORMS. LIFT AND INFLOW ALONG THE OUTFLOW BOUNDARIES
ASSOCIATED WITH THE THUNDERSTORM DEVELOPMENT SHOULD LEAD TO RENEWED
UPDRAFT AND MIGRATION TO PORTIONS OF THE UPPER RIO GRANDE VALLEY. IN
ADDITION TO THE TORNADO THREAT FROM THESE STORMS...VERY LARGE HAIL
AND EXTREME RAINFALL TOTALS ARE ALSO POSSIBLE.

AT THIS TIME...THE THUNDERSTORMS REMAIN ABOUT 30 MILES NORTH OF
ZAPATA AND JIM HOGG COUNTIES MOVING SOUTH AT 10 MPH. CONTINUE TO
MONITOR NOAA WEATHER RADIO...COMMERCIAL RADIO OR TELEVISION OR YOUR
LOCAL CABLE OUTLET FOR THE LATEST INFORMATION CONCERNING THESE
THUNDERSTORMS APPROACHING OUR NORTHERN REGION.

HAVE ADJUSTED ZNS TO REFLECT CURRENT TSTM TRENDS AND PROBABLE AREA
OF +TSRA.

&&

.PREV DISCUSSION AT 131 PM...
THUNDERSTORMS ASSOCIATED WITH THIS MORNINGS MCS CONTINUE TO MOVE
THROUGH SOUTH CENTRAL TEXAS THIS AFTERNOON...WITH ACTIVITY
CURRENTLY STAYING NORTH OF CRP AREA. TEMPERATURES IN THE UPPER
VALLEY REACHING NEAR 90 RIGHT NOW...WHILE THE LOWER VALLEY IS
STUCK UNDER A STUBBORN CLOUD DECK. WESTERN SECTIONS WILL CONTINUE
TO DESTABILIZE...AND LIKELY WAIT FOR SOME TYPE OF TRIGGER TO MOVE
IN FRO THE NORTH. STARTING TO SEE A FEW CLOUDS STREAKS OFF THE
MOUNTAINS TO THE SOUTHWEST...SO SOME OROGRAPHIC INITIATION IS
PRETTY CLOSE. SPC HAS AREAS WEST OF US 281 IN THE SLIGHT RISK
TODAY. THE EASTERN REGIONS WILL SEE LESS OF A THREAT DUE TO
AFOREMENTIONED CLOUD COVER AND CAPPING AND REDUCED DAYTIME
HEATING. THUNDERSTORM CHANCES WILL CONTINUE THROUGH THE OVERNIGHT
HOURS...WITH THE BIGGEST THREAT REMAINING NORTH OF THE VALLEY.
SOME THUNDERSTORMS ARE POSSIBLE AGAIN TOMORROW...BUT THE UPPER
LEVEL DYNAMICS WILL BE FARTHER NORTH AND WILL HAVE TROUBLE
REACHING DEEP SOUTH TEXAS. THE UPPER LOW WILL MOVE TO THE
NORTHEAST BY WEDNESDAY...AND WILL BE REPLACED WITH WEAK RIDGING.
THIS AND DRIER AIR ALOFT WILL KEEP PRECIPITATION AT BAY AND ALLOW
TEMPS TO GRADUALLY INCREASE THROUGH THE WEEKEND...REACHING 5 TO 7
DEGREES ABOVE NORMAL.

&&

.MARINE...MODERATE SOUTHEAST WINDS WILL CONTINUE FOR THE NEXT
SEVERAL DAYS AS SURFACE LOW PRESSURE OVER MEXICO INTERACTS WITH HIGH
PRESSURE OVER THE GULF TO MAINTAIN THE TIGHT PRESSURE GRADIENT.
SMALL CRAFT ADVISORIES ARE LIKELY FOR THE LAGUNA MADRE AGAIN
TUESDAY. SHOWERS AND THUNDERSTORMS REMAIN POSSIBLE THROUGH THURSDAY
AS A SLOW MOVING UPPER LOW MOVES ACROSS NORTH TEXAS.

&&

.AVIATION...BREEZY SE WINDS WILL DECOUPLE OVERNIGHT WITH LLJ
ADVECTING IN MVFR CIGS. AND GUSTY SOUTHEAST SURFACE WINDS WILL
PERSIST THIS AFTERNOON AND WILL RETURN TUESDAY AFTERNOON. MVFR CIGS
WILL LIFT AND SCT BY LATE AM AND WINDS WILL MIX DOWN WITH SE WINDS
20G30KTS BY AFTERNOON WITH ISOLD SHRA/TSRA PRODUCING TEMPO MVFR TO
IFR CIGS/VIS.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  74  86  75  87 /  20  20  10  10
BROWNSVILLE          74  88  74  88 /  20  20  10  10
HARLINGEN            72  88  73  91 /  20  20  10  10
MCALLEN              73  91  74  93 /  20  20  10  10
RIO GRANDE CITY      74  93  74  95 /  20  20  10  10
SOUTH PADRE ISLAND   75  82  74  84 /  20  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
SCA GMZ130-132-135 THROUGH 7 PM.
&&

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

58/55/MARTINEZ

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
745 PM CDT MON APR 30 2007

TXZ248>257-011200-
ZAPATA-JIM HOGG-BROOKS-KENEDY-STARR-HIDALGO-INLAND WILLACY-
INLAND CAMERON-COASTAL WILLACY-COASTAL CAMERON-
745 PM CDT MON APR 30 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS.

.DAY ONE...REMAINDER OF TONIGHT.

THERE IS A RISK OF SEVERE THUNDERSTORMS FOR ZAPATA...JIM HOGG AND
BROOKS COUNTIES THROUGH MIDNIGHT. THE MAIN THREAT IS LARGE HAIL AND
HEAVY RAINFALL...WITH SOME OF THESE SEVERE THUNDERSTORMS CAPABLE OF
PRODUCING A TORNADO.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR WESTERN PORTIONS
OF DEEP SOUTH TEXAS TUESDAY. RIP CURRENT RISK MAY INCREASE TO
MODERATE ON TUESDAY.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS POSSIBLE TONIGHT AND TUESDAY...ESPECIALLY FOR
THE NORTHERN COUNTIES OF THE RIO GRANDE VALLEY. SPOTTERS AND
EMERGENCY MANAGERS SHOULD STAY TUNED TO DEVELOPING WEATHER.

PHILO

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
649 PM CDT MON APR 30 2007

TXZ248>251-010045-
JIM HOGG TX-ZAPATA TX-BROOKS TX-KENEDY TX-
649 PM CDT MON APR 30 2007

...A TORNADO WATCH IS IN EFFECT JUST NORTH OF THE THE RIO GRANDE
VALLEY...

...STRONG TORNADIC THUNDERSTORMS WITH LARGE HAIL CONTINUE TO DRIFT
SOUTH TOWARD JIM HOGG...ZAPATA AND BROOKS COUNTIES...

A TORNADO WATCH REMAINS IN EFFECT FOR AREAS JUST NORTH OF THE RIO
GRANDE VALLEY UNTIL 10 PM. SEVERE TORNADIC THUNDERSTORMS HAVE
PERSISTED IN NORTHERN AND CENTRAL DUVAL COUNTY EARLY THIS
EVENING...AND THESE DANGEROUS THUNDERSTORMS HAVE BEEN DRIFTING
SLOWLY SOUTH TOWARD NORTHERN JIM HOGG AND ZAPATA COUNTIES. THE
ATMOSPHERE REMAINS VERY SUPPORTIVE FOR THE PERSISTENCE OF THESE
THUNDERSTORMS. LIFT AND INFLOW ALONG THE OUTFLOW BOUNDARIES
ASSOCIATED WITH THE THUNDERSTORM DEVELOPMENT SHOULD LEAD TO RENEWED
UPDRAFT AND MIGRATION TO PORTIONS OF THE UPPER RIO GRANDE VALLEY. IN
ADDITION TO THE TORNADO THREAT FROM THESE STORMS...VERY LARGE HAIL
AND EXTREME RAINFALL TOTALS ARE ALSO POSSIBLE.

AT THIS TIME...THE THUNDERSTORMS REMAIN ABOUT 40 MILES NORTH OF
ZAPATA AND JIM HOGG COUNTIES MOVING SOUTH AT 10 MPH. CONTINUE TO
MONITOR NOAA WEATHER RADIO...COMMERCIAL RADIO OR TELEVISION OR YOUR
LOCAL CABLE OUTLET FOR THE LATEST INFORMATION CONCERNING THESE
THUNDERSTORMS APPROACHING OUR NORTHERN REGION. PHILO

PHILO

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BROWNSVILLE TX
852 PM CDT MON APR 30 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0842 PM     HAIL             20 WSW HEBBRONVILLE     27.21N 98.99W
04/30/2007  M1.75 INCH       ZAPATA             TX   TRAINED SPOTTER

            WEATHER SPOTTER REPORTED GOLF BALL SIZE HAIL.

&&

BC