Red Flag Warning 18, NWS Brownsville, TX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
918 AM CDT TUE APR 25 2006

.UPDATE...
COLD FRONT MOVING THROUGH TEXAS CURRENTLY ALIGNED FROM DFW TO JCT.
STILL EXPECTING THUNDERSTORMS TO DEVELOP FROM THE HILL COUNTRY TO
NORTHEAST TEXAS LATER THIS AFTERNOON AND PROPAGATE EAST AND SOUTH.
SPC HAS US UNDER A SLIGHT RISK OF SEVERE WEATHER...MAINLY FOR THIS
EVENING. LOOKS LIKE DEEP SOUTH TEXAS WOULD SEE THE TAIL END OF A
MCS SQUALL LINE...BETWEEN 6PM AND 6AM...DEPENDING ON HOW SOON THE
INITIAL STORMS DEVELOP. CONDITIONS FOR SEVERE WEATHER LOOK
MARGINAL IN THE VALLEY WITH CAPPING POSSIBLY ENDING UP TOO STRONG...BUT
LOOK BETTER FOR DESPARATELY NEEDED RAINFALL. HAVE ISSUED UPDATE TO
INCREASE POPS AND PUT MENTION OF SEVERE IN.

&&

.MARINE...
BUOY 42020 CURRENTLY REPORTS A SOUTHEAST WIND NEAR 11 KNOTS WITH
SEAS AROUND 3.5 FEET WITH A PERIOD OF 6 SECONDS. WILL MAINTAIN A
SMALL CRAFT ADVISORY FOR THE BAY AND NEARSHORE GULF WATERS TODAY
AS SHORT RANGE GUIDANCE TRIES TO SPIN UP A SURFACE LOW OVER THE
WESTERN PORTIONS OF THE BRO CWA LATER TODAY WHICH WILL TIGHTEN UP
THE PGF. THE CURRENT CWF WORDING LOOKS OK WITH NO MAJOR CHANGES
NEEDED AT THE MOMENT. A SMALL CRAFT ADVISORY MAY ALSO NEED TO BE
POSTED FOR THE FAR OFFSHORE WATERS OF DEEP SOUTH TEXAS LATER THIS
WEEK THROUGH THE FIRST HALF OF THE WEEKEND DUE TO STRONG WINDS AND
ROUGH SEAS. OTHERWISE...MODERATE WINDS AND SEAS ARE EXPECTED FOR
THE REMAINDER OF THE FORECAST.

&&

.AVIATION...
VSBL SATELLITE IMAGERY AND SURFACE OBS INDICATES THAT THE MORNING
LOW CEILINGS HAVE BECOME MORE RAGGED TODAY...BUT DAYTIME HEATING
WILL LIKELY REGENERATE MORE SC LATER THIS MORNING AND INTO THE
AFTERNOON. WILL HOLD OFF ON ANY MENTION OF CONVECTION UNTIL LATER
IN THE TAF PERIOD AS THE COLD FRONT IS STILL LOCATED WELL NORTH OF
THE BRO CWA AND THE AIRMASS WILL NEED TO DESTABILIZE MORE LATER
THIS AFTERNOON TO INCREASE THE CONVECTIVE POTENTIAL TO DEEP SOUTH
TEXAS. CURRENT TAF WORDING LOOKS OK.

&&

.PREV DISCUSSION... /ISSUED 300 AM CDT TUE APR 25 2006/

DISCUSSION...CONVECTIVE ACTIVITY WEST OF ZAPATA COUNTY MATERIALIZED
LAST EVENING AS FORECAST...AND A MID LEVEL CLOUD SHIELD MOVED ACROSS
DEEP SOUTH TEXAS THE LAST COUPLE OF HOURS. EMBEDDED LIGHTNING DIED
OUT BEFORE REACHING THE RIO GRANDE HOWEVER.

SOUTHEAST TEXAS IS IN THE SLIGHT RISK FOR SEVERE WEATHER CATEGORY
FOR TODAY. MUCH OF THE DISCUSSION IS FOCUSED ON AREAS TO THE NORTH
OF DEEP SOUTH TEXAS...AS A COLD FRONT WILL BE PUSHING SOUTH INTO
CENTRAL TEXAS TODAY AND MERGING WITH A DRY LINE. THE LAST SOUNDING
FOR BRO 25/00Z SHOWS A JAGGED YET DEEP ISOTHERMAL LAYER FROM 2000
FROM 6000 FT. THE SOUNDING BECOMES DECIDEDLY MORE UNSTABLE ABOVE THE
STABLE LAYER HOWEVER. THE DRT SOUNDING FROM 25/00Z IS MUCH MORE
FAVORABLE FOR CONVECTIVE DEVELOPMENT TODAY. THE H5 PATTERN IS FLAT
FROM THE SOUTHWEST WITH LITTLE FORCING INDICATED. ANY CONVECTION IS
LIKELY TO MOVE INTO THE AREA FROM THE NORTH AND WEST...AND MORE
LIKELY TONIGHT AT THE EARLIEST.

THE INHERITED FORECAST HAD REASONABLE POP AMOUNTS AND ONLY TWEAKED
SOME OF THE TIMES SLIGHTLY. THE GFS HAS BEEN CONSISTENT THE LAST TWO
OR THREE RUNS WITH POPS AND TEMPS...SO HAVE MODERATE TO HIGH
CONFIDENCE IN THE CURRENT NUMBERS.

AN H5 RIDGE AXIS DOES SET UP OVER TEXAS LATE WEDNESDAY TO EARLY
THURSDAY...BUT NORTH TO NORTHEAST WINDS WILL PILE UP ALONG THE
SIERRA MADRE...AND SOUTHWEST FLOW WILL CONTINUE IN THE MID
LEVELS...SO SIGNIFICANT CLOUD COVER WILL PREVAIL. AN H5 LOW MOVES
OVER THE GADSDEN PURCHASE THURSDAY NIGHT...AND WITH DIFFLUENCE ALOFT
WILL SPARK THUNDERSTORMS NEAR THE BIG BEND...EVEN AS LOW LEVEL FLOW
RETURNS TO SOUTHEAST FOR DEEP SOUTH TEXAS. SHOWERS COULD REACH
ZAPATA COUNTY BY FRIDAY MORNING. WITH THE H5 LOW APPROACHING WEST
TEXAS ON FRIDAY...AND A SOLID SOUTHEAST LOW LEVEL FLOW FOR DEEP
SOUTH TEXAS...STORMS COULD FIR TO THE NORTH...AGAIN POSSIBLY
DRIFTING SOUTH INTO THE AREA FRIDAY NIGHT INTO SATURDAY MORNING.
ANOTHER FRONT...AN ADJUNCT TO THE MAIN LOW MOVING INTO THE UPPER
MISSISSIPPI VALLEY...PUSHES SOUTH SATURDAY NIGHT AND WILL BRING A
LINE OF THUNDERSTORMS TO THE BROWNSVILLE AREA SUNDAY MORNING. LIGHT
NORTHEAST WINDS SET UP AFTER THE FRONT THROUGH MONDAY...WHILE THE
FRONT LINGERS OFFSHORE. AMPLIFIED H5 RIDGING SETS UP OVER THE
WESTERN UNITED STATES BEYOND NEXT MONDAY.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...SCA GMZ 130-132-135-150-155.
&&

64/60/MARTINEZ

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
845 AM CDT TUE APR 25 2006

TXZ248>257-261100-
BROOKS-COASTAL CAMERON-COASTAL WILLACY-HIDALGO-INLAND CAMERON-
INLAND WILLACY-JIM HOGG-KENEDY-STARR-ZAPATA-
845 AM CDT TUE APR 25 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR DEEP SOUTH TEXAS.

.DAY ONE...REST OF TODAY AND TONIGHT.

A SMALL CRAFT ADVISORY WILL BE IN EFFECT FOR THE LAGUNA MADRE AND
GULF OF MEXICO WATERS EAST OF PADRE ISLAND OUT TO 20 NAUTICAL MILES
OFFSHORE LATER THIS MORNING THROUGH EARLY THIS AFTERNOON...AS WINDS
WILL INCREASE TO AROUND 20 KNOTS. THESE WINDS WILL LIKELY BRING A
MODERATE RISK OF RIP CURRENTS TO THE LOWER TEXAS COAST. ALSO...
ISOLATED TO SCATTERED THUNDERSTORMS MAY PRODUCE LOCALLY HEAVY
RAINFALL OVER PORTIONS OF DEEP SOUTH TEXAS LATE TODAY AND TONIGHT.
SOME OF THE THUNDERSTORMS HAVE THE POTENTIAL OF BEING STRONG TO
SEVERE POSSIBLY PRODUCING HAIL AND DAMAGING WINDS ESPECIALLY IN THE
LATE AFTERNOON AND EVENING HOURS. NO OTHER HAZARDOUS WEATHER IS
EXPECTED.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

A SMALL CRAFT ADVISORY MAY NEED TO BE POSTED FOR THE FAR OFFSHORE
WATERS OF DEEP SOUTH TEXAS THURSDAY THROUGH SATURDAY DUE TO STRONG
WINDS AND ROUGH SEAS. ALSO...THUNDERSTORMS MAY PRODUCE LOCALLY HEAVY
RAINFALL OVER PORTIONS OF DEEP SOUTH TEXAS DURING THE PERIOD. SOME
OF THE THUNDERSTORMS HAVE THE POTENTIAL OF BEING STRONG TO SEVERE...
PRODUCING SMALL HAIL AND DAMAGING WINDS. NO OTHER HAZARDOUS WEATHER
IS ANTICIPATED THROUGH THE PERIOD.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND THIS
EVENING.

SPEECE