Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 010534 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1234 AM CDT SAT AUG 1 2015

.DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
&&

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
MOSTLY HIGH CLOUDS ACROSS THE CWA LATE TONIGHT. EXPECT VFR
CONDITIONS TO PREVAIL THE REST OF TONIGHT INTO SATURDAY EVEN AS
LOW TO MID LEVEL MOISTURE CONTINUES TO INCREASE ACROSS THE COASTAL
SECTIONS OF THE CWA SAT AFTERNOON AS THE WEAK 500MB LOW/INVERTED
TROUGH ACROSS THE WESTERN GULF OF MEXICO MOVES WESTWARD. ISOLATED
TO SCATTERED CONVECTION WILL DEVELOP ACROSS THE COASTAL SECTIONS
AND MOVE INLAND SAT MORNING. EXPECT SHOWERS IN THE VICINITY
THROUGH 17Z SATURDAY AND THUNDERSTORMS IN THE VICINITY AFTER 17Z
SATURDAY THROUGH 03Z SUNDAY.
&&

.PREV DISCUSSION... /ISSUED 659 PM CDT FRI JUL 31 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...VFR CONDITIONS TO PREVAIL THIS EVENING WITH A MID TO
LEVEL OVERCAST FROM CONVECTION OFFSHORE AND ACROSS OVER SOUTH
CENTRAL TEXAS. WEAK DISTURBANCE OVER THE WESTERN GULF TO DRIFT
WEST OVERNIGHT AND SATURDAY PROVIDING AN INCREASE IN MOISTURE TO
PRODUCE MULTI-LAYERED CLOUD COVER WITH CELLING BASES MAINLY AT
VFR LEVELS. HIGH RESOLUTION MODELS INDICATE BELOW 20 PERCENT
CHANCE OF MVFR OR LOWER CEILINGS. THE ADDED MOISTURE TO PROVIDE A
LOW CHANCE OF SHOWERS OR A THUNDERSTORM IN NEAR THE COAST
OVERNIGHT AND EARLY SATURDAY MORNING WITH SOME CONVECTION WORKING
INLAND OR DEVELOPING OVER LAND SATURDAY AFTERNOON WITH THE HEATING
OF THE DAY. WINDS ARE EXPECTED TO BE LIGHT AND VARIABLE OVERNIGHT
BECOMING EASTERLY AT LIGHT LEVELS SATURDAY.

PREV DISCUSSION... /ISSUED 320 PM CDT FRI JUL 31 2015/

SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...BRO RADAR SHOWS ISOLATED
SHOWERS OVER THE LOWER TEXAS GULF WATERS MAINLY 40 TO 60 NAUTICAL
MILES EAST OF PADRE ISLAND. LATEST SATELLITE IMAGERY SHOWS MID TO
HIGH LEVEL CLOUDINESS OVER DEEP SOUTH TEXAS THIS AFTERNOON WHICH
HELD TEMPERATURES DOWN A FEW DEGREES FROM YESTERDAY. THIS CLOUD
COVER AND SHOWER ACTIVITY IS ASSOCIATED WITH A WEAK 500MB
LOW/INVERTED TROUGH OVER THE WESTERN GULF OF MEXICO. THIS FEATURE
OVER THE WESTERN GULF OF MEXICO WILL CONTINUE TO MOVE WEST-SOUTHWEST
THROUGH THE PERIOD. THE 12Z BRO SOUNDING SHOWS A PRECIPITABLE WATER
VALUE OF 1.66 INCHES. LOW TO MID LEVEL MOISTURE WILL CONTINUE TO
INCREASE ACROSS THE WESTERN GULF OF MEXICO TONIGHT THROUGH SATURDAY
NIGHT. THIS WILL SUPPORT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS PORTIONS OF DEEP SOUTH TEXAS TONIGHT AND
SATURDAY WITH LINGERING SHOWERS AND THUNDERSTORMS SATURDAY NIGHT
OVER THE GULF. THE ABUNDANT CLOUD COVER OVERNIGHT SHOULD ALLOW LOW
TEMPERATURES TO FALL ONLY INTO THE UPPER 70S...EXCEPT IN THE MID 70S
ACROSS THE NORTHERN RANCHLANDS WITH A LITTLE LESS CLOUDINESS.

LONG TERM /SUNDAY THROUGH FRIDAY/...AFTER THE BRIEF OPPORTUNITY
FOR CONV DUE TO THE WEAKNESS IN THE OVERALL RIDGING MOVING OVER
DEEP SOUTH TX THIS WEEKEND THE PATTERN WILL QUICKLY SHIFT BACK TO
STRONG 500 MB RIDGING NEXT WEEK. THE 500 MB RIDGING WILL REBUILD
OVER THE REGION NEXT WEEK AS MAJOR 500 MB TROUGHS BUILD OVER THE
WEST AND EAST COASTS. DEEP LAYER TROPICAL MOISTURE LEVELS AND CAPE
VALUES WILL BOTTOM OUT WHILE 1000-500 MB LAYER THICKNESS VALUES
WILL STEADILY INCREASE. THE BOTTOM LINE FOR THE RGV WILL BE A
RETURN OF SUMMER SUNSHINE AND TEMPS ABOVE CLIMO FOR EARLY AUGUST.
BOTH THE ECMWF AND THE GFS 500 MB FIELDS ARE IN GOOD AGREEMENT IN
THE DEVELOPMENT OF THIS PATTERN AND THE ASSOCIATED DRYING OUT OF
THE ATMS NEXT WEEK. WILL LEAN A LITTLE CLOSER TO THE ECMWF MAX AND
MIN TEMPS VERSUS THE GFS MEX NUMBERS AS THE GFS IS A LITTLE BIT
SLOWER IN REFLECTING THE RETURN OF 100+ TEMPS OUT WEST. THE GFS
MEX POPS ALSO WANT TO TREND TOWARDS SOME SLGT CHC POPS OUT AT DAYS
6 AND 7. BELIEVE THAT THIS IS ALSO UNREALISTIC CONSIDERING THE
STRENGTH OF THE 500 MB RIDGING.

MARINE...NOW THROUGH SATURDAY NIGHT...FAVORABLE MARINE
CONDITIONS WILL PREVAIL ALONG THE LOWER TEXAS COAST NOW THROUGH
SATURDAY NIGHT. SEAS WERE AROUND 1 FOOT WITH WEST-NORTHWEST WINDS
NEAR 2 KNOTS AT BUOY020 THIS AFTERNOON. LIGHT AND VARIABLE WINDS
WILL CONTINUE ACROSS THE LOWER TEXAS COASTAL WATERS THIS AFTERNOON
DUE TO A WEAK PRESSURE GRADIENT ACROSS THE WESTERN GULF OF MEXICO.
LIGHT SOUTHERLY WINDS WILL PREVAIL ACROSS THE WESTERN GULF TONIGHT
WITH BROAD AND WEAK LOW PRESSURE ACROSS THE NORTHERN GULF. LIGHT
AND VARIABLE WINDS WILL PREVAIL ACROSS THE LOWER TEXAS COAST
SATURDAY AS THE PRESSURE GRADIENT REMAINS WEAK ACROSS THE WESTERN
GULF. WINDS AND SEAS WILL BE HIGHER IN AND NEAR THUNDERSTORMS
ACROSS THE WESTERN GULF NOW THROUGH SATURDAY NIGHT AS A WEAK MID
TO UPPER LEVEL DISTURBANCE MOVES OVERHEAD.

SUNDAY THROUGH WEDNESDAY...A FAIRLY WEAK TO MODERATE PGF WILL
PERSIST ON THROUGH THE FIRST HALF OF NEXT WEEK AS THE SURFACE
RIDGING PERSISTS OVER THE GULF OF MEX. THIS MAY ALLOW FOR SOME
BUILDING OF SEAS LATE IN THE CWF PERIOD AS THE LIGHT TO MODERATE SE
WINDS PERSISTS. BUT AT THIS POINT IN TIME NO SCA CONDITIONS ARE
EXPECTED FOR EITHER THE BAY OR GULF WATERS.
&&

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

$$

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