Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 291933
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
233 PM CDT FRI APR 29 2016

.SHORT TERM /NOW THROUGH SATURDAY NIGHT/...SUBTROPICAL JET ACROSS
MX IS MOVING IN HIGHER LEVEL MOISTURE ACROSS S TEXAS MOST OF
TODAY. THIS WILL CONTINUE TO STREAM HIGH AND MID LEVEL CLOUDS
ACROSS THE REGION THROUGH THE DAY. HAZE COMING FROM AGRICULTURAL
BURNING IN THE YUCATAN PENINSULA WILL REMAIN THROUGH THE DAY AND
INTO TOMORROW AS THE SE LOW LEVEL FLOW PREVAIL THROUGH THE SHORT
TERM. THE STRONG LOW PRESSURE CENTERED OVER THE GREAT BASIN IS
PROVIDING FAVORABLE UPPER DIFFLUENCE ACROSS NORTH AND CENTRAL
TEXAS THIS AFTERNOON. A LINE OF SHOWERS AND THUNDERSTORMS ARE
STARTING TO FIRE UP AS LOW LEVEL SOUTHERLY FLOW FEEDS GULF
MOISTURE INTO THE REGION. THE MODELS SHOW SOME DISAGREEMENT AS TO
ANY DEVELOPMENT THIS AFTERNOON THIS FAR INTO SOUTH TEXAS AS
INSTABILITY LOWERS AS WE LOSE DAYTIME HEATING. WITH THAT SAID,
CONVECTION COULD PUSH DOWNSTREAM TOWARDS THE S CENTRAL TEXAS AND
COULD IMPACT THE FAR NORTHERN COUNTIES BY THE LATE EVENING HOURS.
MAIN THREAT WILL BE STRONG WINDS AND HAIL. PRECIPITATION TOTALS
COULD BE HIGHER WITH STRONGER THUNDERSTORMS. DUE TO THE ABUNDANCE
OF CLOUD COVER...TEMPERATURES TODAY WERE MODIFIED TO A FEW DEGREES
LOWER AS IT WILL BE DIFFICULT TO REACH THE UPPER 90S WITH THE OVC
TO BKN THICK CLOUD DECK. THE GUSTY WINDS WILL PREVAIL THROUGH THE
DAY AND WEAKEN BY THE LATE EVENING BECOMING LIGHTER AFTER
MIDNIGHT.

THE UPPER TROUGH LIFTS NORTHEAST INTO THE NORTHERN ROCKIES
PUSHING A WEAK BOUNDARY EARLY IN THE MORNING HOURS. THE SE FLOW
WILL WEAKEN CLOSE TO 10 KNOTS CLOSER TO THE MORNING HOURS. THE
ABUNDANCE OF SMOKE/HAZE IN THE AIR IN TO THE MOISTURE CONTENT WILL
ALLOW FOR ANOTHER AROUND OF HAZE AND PATCHY FOG MIX TONIGHT
ESPECIALLY IN THE MORNING HOURS. THERE WILL BE A WEAK SHIFT IN THE
SE FLOW FOR A SHORT PERIOD. THE TAIL END OF THE BOUNDARY COULD
ENHANCE CONVECTION OVER S TEXAS SATURDAY. EXPECT THE BETTER
CHANCES TO REMAIN TOWARDS THE NORTHERN COUNTIES. SAT AFTERNOON AND
OVERNIGHT HOURS...DRY AIR WILL MAKE ITS WAY INTO THE CWA WITH SW
FLOW ALOFT LIMITING ANY ADDITIONAL RAINFALL FOR THE SHORT TERM
PERIOD. TEMPERATURES WILL REMAIN IN THE MID 90S AND OVERNIGHT
LOW`S IN THE UPPER 70S.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...THE SECOND OF TWO MID LVL
SHORT WAVE TROUGHS WILL DIG SOUTH OVER THE FOUR CORNERS REGION
SAT NIGHT...WITH CONTINUED SOUTHWEST FLOW ALOFT OVER DEEP SOUTH
TEXAS AND THE RGV. THE BROAD TROUGH STRETCHING FROM THE WEST
COAST TO THE CENTRAL PLAINS WILL NOT PROVIDE A LOT OF SUPPORT TO
THE TRAILING END OF A COLD FRONT MORE OR LESS WASHED OUT OVER THE
AREA ON SUNDAY. THE FOUR CORNERS LOW WILL BECOME ABSORBED IN THE
OVERALL PATTERN BY MON AS RIDGING BUILDS OVER THE WEST. THE
RIDGING WILL HELP PUSH A MORE DEFINITIVE FRONT THROUGH DEEP SOUTH
TEXAS AND THE RGV LATE MONDAY OR MONDAY NIGHT. THUS...WEATHER
CHANCES WILL BE BEST SUNDAY THROUGH MONDAY NIGHT BEFORE
IMPROVEMENTS DUE TO SPREADING HIGH PRESSURE TAKE OVER FOR THE REST
OF THE LONG TERM...OR THE MID AND LATTER PARTS OF THE WEEK.

BACK TO THE FRONT SATURDAY NIGHT INTO SUNDAY. A WEAK COLD FRONT WILL
LINGER ACROSS DEEP SOUTH TEXAS SATURDAY NIGHT INTO SUNDAY SINCE IT
WILL NOT PUSH THROUGH WITH ANY SENSE OF URGENCY OR STRENGTH. THE
COMBINATION OF THE WEAK FRONTAL BOUNDARY...LOW LEVEL MOISTURE AND
DAYTIME HEATING WILL SUPPORT ISOLATED TO SCATTERED CONVECTION ON
SUNDAY. THE STORM PREDICTION CENTER /SPC/ HAS PLACED ALL OF DEEP
SOUTH TEXAS UNDER A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR SUNDAY
AND SUNDAY NIGHT WITH THE MAIN THREATS BEING SMALL HAIL AND GUSTY
WINDS.

ONSHORE...IF NOT SOUTHEAST...SURFACE FLOW WILL MORE OR LESS CONTINUE
SUNDAY IN SPITE OF THE FIRST FRONT...ALLOWING ABUNDANT MOISTURE TO
REMAIN IN PLACE ON MONDAY AHEAD OF THE NEXT COLD FRONT AND WEAK
UPPER LEVEL SHORT WAVE. A FEW TENTHS OF AN INCH TO AN INCH OF RAIN
WILL BE POSSIBLE ON MONDAY AS SURFACE HIGH PRESSURE BEGINS TO
PENETRATE INTO THE AREA...PROVIDING WEAK THOUGH IMPORTANT LOW LEVEL
LIFT.

ECMWF/GFS ARE IN REASONABLE AGREEMENT ON THE TIMING OF THE PASSAGE
OF THE LATE MONDAY COLD FRONT. BOTH SUGGEST THAT THE BEST LIFT/
CHANCE OF STRONGER CONVECTION WILL BE LATE MONDAY OR EVEN MONDAY
NIGHT. BOTH MODELS HANG ON TO RAIN CHANCES INTO TUESDAY...THOUGH THE
ECMWF COVERAGE/AMOUNTS IN THE MODEL SEEM A BIT MORE ROBUST THROUGH
TUESDAY. RAIN CHANCES WILL BE PALPABLE MONDAY THROUGH TUESDAY AS
MOISTURE POOLS ACROSS THE AREA. DRIER AIR WILL FILTER INTO THE
REGION TUESDAY NIGHT INTO WEDNESDAY AS HIGH PRESSURE SPREADS OVER
THE AREA.

&&

.MARINE...
NOW THROUGH SATURDAY NIGHT...THE GRADIENT REMAINS STRONG OVER THE
GULF WATERS AT THIS TIME KEEPING A SOUTHERLY WIND UP TO 20 TO 22
KNOTS AND GUST UP TO 25 KNOTS. ABUNDANT CLOUD COVER FROM THE
SUBTROPICAL JET KEEP STREAMING ACROSS OUR AREA KEEPING TEMPS IN
THE MID 80S. THE GRADIENT WILL BEGIN TO WEAKEN AS A SURFACE LOW
PRESSURE MOVES OVER THE REGION. THE WINDS WEAKEN AND GRADUALLY
LOWER SEAS. THE SE FLOW WILL BEGIN TO SHIFT MORE EASTERLY INTO
SATURDAY WITH A TAIL END OF A WEAK BOUNDARY MOVING ACROSS THE
REGION. THE BETTER CHANCE OF SHOWERS AND THUNDERSTORMS WILL BE
MAINLY OVER THE NORTHERN PORTION OF THE MARINE ZONES. SEAS BEGIN
TO LOWER TO 5 TO 6 BY THE END OF THE SHORT TERM PERIOD.

SUNDAY THROUGH TUESDAY...LIGHT TO MODERATE EAST SOUTHEAST WINDS WILL
PREVAIL LOCALLY...JUST SOUTH OF A FRONTAL BOUNDARY ALONG THE MIDDLE
AND UPPER TEXAS COASTAL WATERS. THE FRONT SHOULD PUSH THROUGH MORE
CONVINCINGLY BY MONDAY WITH REINFORCING HIGH PRESSURE PUSHING
SOUTH FROM THE SOUTHERN HIGH PLAINS. WINDS WILL SHIFT TO NORTHEAST
AND STRENGTHEN LATE MONDAY AND MONDAY NIGHT WITH WINDS POSSIBLY
GETTING ABOVE 20 KNOTS ON THE GULF MONDAY NIGHT.
SUBSEQUENTLY...SMALL CRAFT ADVISORY CONDITIONS WILL BRIEFLY BE
POSSIBLE TUESDAY AS WAVE HEIGHTS RESPOND BY BUILDING TO SEVEN FEET
FOR A FEW HOURS. CONDITIONS WILL IMPROVE TUESDAY NIGHT AND
WEDNESDAY AS HIGH PRESSURE SPREADS OVER THE AREA AND SHIFTS EAST.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  85  77  86 /  10  20  10  20
BROWNSVILLE          78  89  77  88 /  10  20  10  20
HARLINGEN            77  91  76  90 /  10  20  10  20
MCALLEN              77  95  77  93 /  10  20  10  20
RIO GRANDE CITY      76  95  75  95 /  10  20  10  20
SOUTH PADRE ISLAND   77  81  77  83 /  10  20  10  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 10 PM CDT THIS EVENING FOR
     GMZ130-132-135.

     SMALL CRAFT ADVISORY UNTIL 7 AM CDT SATURDAY FOR GMZ150-155-170-
     175.

&&

$$

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