Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 302329
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
629 PM CDT SAT AUG 30 2014

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

&&

.AVIATION...TSRA ON THE DECREASE JUST WEST OF MFE WITH POSSIBILITY
OF A SHOWER OR TWO MOVING INTO THAT TERMINAL THROUGH 02Z. MUCH
LIKE THE PAST FEW NIGHTS...SHORT RANGE MODELS SHOW SHRA/TSRA
INCREASE ALONG THE COASTAL COUNTIES AFT 07Z. HAVE VCSH AT BRO AND
HRL AFT 07Z LASTING INTO THE MORNING WITH TSRA POSSIBLE AFT 14Z.
VFR CONDS EXPECTED AT THE TERMINALS WITH THE EXCEPTION OF IN
HEAVIER SHRA/TSRA WHERE MVFR CONDS WILL BE POSSIBLE. CHANCES OF
PRECIPITATION WILL WANE IN THE COASTAL AREAS SUNDAY AFTERNOON BUT
INCREASE ACROSS THE MIDDLE VALLEY INCLUDING MFE.

&&

.PREV DISCUSSION... /ISSUED 302 PM CDT SAT AUG 30 2014/

SHORT TERM.../NOW THROUGH SUNDAY NIGHT/...AS AN UPPER LEVEL TROUGH
MOVING INTO THE CENTRAL PLAINS LOWER HEIGHTS AND BEGINS TO LIFT
NORTHEAST...A WEAK MID TO UPPER LEVEL CIRCULATION REMAINS ALMOST
STATIONARY OVER THE LOWER TEXAS GULF COAST THROUGH THE SHORT TERM
FORECAST. DEEP SOUTH TEXAS IS IN THE MIDDLE OF BROAD HIGH OVER THE
PACIFIC AND ANOTHER HIGH ACROSS THE SOUTHEAST PLAINS KEEPING THIS
UNSTABLE AREA WITH ABUNDANT MOISTURE OVER US FOR THE NEXT FEW DAYS.
CURRENTLY...ANOTHER ROUND OF CONVECTION IS BEGINNING TO INITIATE AND
WITH COVERAGE  EXPECTED TO INCREASE THROUGH THIS AFTERNOON AND EARLY
EVENING. LATEST PWATS AND RH VALUES CONTINUE TO MAINTAIN VALUES
AROUND 2.5 INCHES ESPECIALLY ALONG THE COASTAL COUNTIES. THIS WILL
FAVOR ONCE AGAIN ANOTHER ROUND OF HEAVY RAINFALL WITH ACCUMULATIONS
BETWEEN 1 TO 3 INCHES POSSIBLE WITH THE STRONGEST THUNDERSTORMS.
THIS WILL CONTINUE TO AFFECT THE COASTAL WATERS AND THE COASTAL
COUNTIES. TONIGHT...CONDITIONS WILL QUIET DOWN CLOSER TO MIDNIGHT
AND WITH DEBRIS CLOUDS LOW TEMPERATURES REMAIN BETWEEN THE MID TO LOW
70S. AFTER MIDNIGHT...EXPECT THE CONVECTION TO INITIATE ALONG THE
COAST FAVORING THE IMMEDIATE COAST SECTIONS OF THE LOWER TEXAS COAST
ESPECIALLY ALONG AND EAST OF HWY 77. THIS WILL EXTEND WESTWARD
DURING THE DAY SUNDAY. THE POTENTIAL FOR RAIN WILL LOWER INLAND
SUNDAY NIGHT AND REMAIN MAINLY OVER THE GULF WATERS WITH A LOW 20
PERCENT AS THE FORECAST AREA IS UNDER THE INFLUENCE OF THIS INVERTED
TROUGH WITH ABUNDANT TROPICAL MOISTURE. HIGH TEMPERATURES WILL BE IN
THE MID TO LOW 90S TODAY AND UPPER 90S INTO SUNDAY ESPECIALLY FOR
THE WESTERN COUNTIES.

LONG TERM /MONDAY THROUGH SATURDAY/...RAIN CHANCES DIMINISH EVER
SO SLIGHTLY MONDAY BEFORE THE NEXT SURGE OF TROPICAL MOISTURE
ENTERS THE REGION TUE-THURSDAY.

MODELS REMAIN PERSISTENT IN TIMING AND PLACEMENT OF THE MOISTURE
ASSOCIATED WITH THE TROPICAL WAVE MOVING INTO THE WESTERN
CARIBBEAN THIS AFTERNOON. NOT EXPECTING ANY DEVELOPMENT PRIOR TO
ITS APPROACH OF THE YUCATAN SUNDAY BUT THE NATIONAL HURRICANE
CENTER CONTINUES WITH A 40 PERCENT CHANCE OF DEVELOPMENT AS IT
MOVES INTO THE BAY OF CAMPECHE AND SOUTHERN GULF OF MEXICO. MODEL
TRENDS SEND A SURGE OF MOISTURE INTO THE RIO GRANDE VALLEY AS
EARLY AS MONDAY NIGHT WHICH IS MUCH FASTER THAN THE LAST FEW MODEL
RUNS. IF THIS SYSTEM DOES NOT REMAINS AN OPEN WAVE AND DOES SHOW
ANY SIGNS OF TIGHTENING NEAR A COMMON CENTER THE LEADING EDGE OF
MOISTURE COULD ARRIVE EARLY. GFS CONTINUES TO SHOW SOME LIMITED
ORGANIZATION WHILE THE ECMWF AND CANADIAN KEEP THE SYSTEM A ROBUST
WAVE. NAM IS THE OUTLIER DEVELOPING A TIGHT CIRCULATION AND
TRACKING THE CENTER ABOUT 70 MILES SOUTH OF THE MOUTH OF THE RIO
GRANDE.

FORECAST REMAINS IN TACT WITH ISOLATED RAIN CHANCES MONDAY THEN
INCREASING TUESDAY PEAKING TUESDAY NIGHT, WEDNESDAY AND THURSDAY.
DEEP TROPICAL MOISTURE WITH PWATS HOVERING BETWEEN 2.25 AND 2.6
INCHES AND MEAN RH OF AROUND 80 PERCENT IN THE 1000-500MB LAYER
SHOULD BE SUFFICIENT FOR GOOD CHANCES OR LIKELY SHOWER AND
THUNDERSTORMS. MAV GUIDANCE HAS BEEN TRENDING UPWARDS WITH THE
POPS DURING THE PEAK TIMES LISTED. GOING FORECAST REMAINS
UNCHANGED WITH STILL SOME TIME TO BUMP POPS UP TO THE LIKELY
CATEGORY AS THE WAVE EMERGES INTO THE SOUTHERN GULF.

THEN AS THE WAVE MOVES WELL INLAND AND DISSIPATES LINGER MOISTURE
HANGS AROUND AT LEAST GIVING THE REGION A LOW END CHANCE OF RAIN
FRIDAY AND SATURDAY.

TEMPERATURE FORECAST TO REMAIN THE SAME WITH SOME INCREASE IN
TEMPS MONDAY THEN A GRADUAL FALL BACK BELOW NORMAL ONCE THE CLOUDS
AND RAIN MOVE BACK INTO THE REGION. EVEN THOUGH THE TEMPERATURES
MIGHT BE COOLER THE HUMIDITY LEVELS WILL BE EXTREMELY HIGH WITH
DEWPOINTS RANGING 75 TO 80 DEGREES. UGGH.

MARINE...NOW THROUGH SUNDAY NIGHT...THE SOUTHEAST WINDS AND SEAS
OVER THE GULF WATERS AND THE LAGUNA WILL REMAIN LIGHT TO MODERATE.
HOWEVER ...THE MAIN IMPACT WILL CONTINUE TO BE THE CONVECTION
THROUGH MOST OF THE SHORT TERM FORECAST. MOST OF THE CONVECTION IS
PRODUCING HEAVY RAIN AND FREQUENT LIGHTNING WHICH COULD PRODUCE
BRIEF OUTFLOWS CLOSE TO THE STORMS. EXPECT THIS ACTIVITY TO
INCREASE IN THE EARLY MORNING HOURS AFTER MIDNIGHT AND CONTINUE
THROUGH MID MORNING. SEAS WILL BE MODERATE BETWEEN 3 TO 5 FEET
OFFSHORE FOR SUNDAY.

MONDAY THROUGH THURSDAY...PRESSURE GRADIENT IS EXPECTED TO
STRENGTHEN AS A TROPICAL WAVE EMERGES OFF THE YUCATAN PENINSULA
SUNDAY NIGHT AND MONDAY. A LONG FETCH OF EAST TO SOUTHEAST WINDS
TO DEVELOP A LONG PERIOD SWELL ACROSS THE CENTRAL AND WESTERN
GULF. SWELLS TO APPROACH SMALL CRAFT ADVISORY LEVELS TUESDAY NIGHT
INTO EARLY THURSDAY. WINDS ACROSS THE OFFSHORE WATERS ARE MORE
DIFFICULT TO TACKLE IF THE WAVE REMAINS FAR ENOUGH SOUTH AND DOES
NOT STRENGTHEN. MARGINAL SMALL CRAFT ADVISORY WINDS MAY DEVELOP
TUESDAY NIGHT INTO WEDNESDAY AS THE WAVE AXIS MAKES IT CLOSEST
APPROACH TO THE LOWER TEXAS COAST. CONDITIONS TO IMPROVE LATER
THURSDAY INTO NEXT WEEKEND WITH THE WAVE MOVING INLAND.

&&

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

$$

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