Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 311953
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
253 PM CDT SUN AUG 31 2014

.SHORT TERM /NOW THROUGH MONDAY NIGHT...CURRENTLY SATELLITE AND
RADAR TREND SHOW ISOLATED SHOWERS AND THUNDERSTORMS OVER WESTERN
CAMERON AND WILLACY COUNTIES. THESE SHOWERS ARE PRODUCING MODERATE
TO HEAVY RAIN IN THE STRONGEST STORMS WITH GUSTY WINDS BETWEEN 25 TO
30 MPH AND SOME A BIT HIGHER WITH OCCASIONAL CLOUD TO GROUND
LIGHTNING. LIGHT SE LOW LEVEL WINDS INTERACTING WITH SOUTH TO
SOUTHWEST WINDS INLAND HAVE DEVELOP AN AREA OF CONVERGENCE RIGHT
ALONG THE COAST ENHANCING THIS CONVECTION IN THE AREA. IN
ADDITION...12Z KBRO SOUNDING INDICATED VALUES OF 2.40 INCHES THIS
MORNING. THE ABUNDANCE IN MOISTURE IN THE ATMS WILL FAVOR CONVECTION
THROUGH THIS AFTERNOON. THIS ACTIVITY WILL NOT COVER AS MUCH AS THE
PREVIOUS DAYS AS THE MID TO UPPER LEVEL VORT THAT WAS OVER THE CWA
LIFTED NORTHEAST INTO THE CENTRAL AND NORTHWEST PORTION OF THE GULF
COAST. THE WESTERN COUNTIES WILL STILL REMAIN DRY AS PWATS ARE NOT
AS FAVORABLE AND THERE IS NO UPPER LEVEL SUPPORT FOR ADDITIONAL
ENHANCEMENT TOWARDS THE WEST. HIGH TEMPERATURES TODAY WILL REACH THE
LOW TO MID 90S ALONG AND EAST OF HWY 281 AND UPPER 90S WEST OF HWY
281.

TONIGHT...DEEP TROPICAL MOISTURE WILL SLOWLY CONTINUE TO MIGRATE NE
WITH A WEAK LOW REMAINING OVER SOUTH CENTRAL TEXAS COAST. MOISTURE
IN THAT AREA OVER THE GULF WATERS REMAINS BETWEEN 65 TO 70 PERCENT
WHICH COULD CONTINUE TO ENHANCE ISOLATED SHOWERS OVERNIGHT INTO EARLY
MONDAY MORNING. LOW TEMPERATURES WILL RANGE BETWEEN MID TO UPPER 70S
WITH LOCATIONS ALONG THE RIVER NEAR THE 80S.

MONDAY...MID TO UPPER LEVEL VORT WILL CONTINUE TO LIFT NORTHEAST WITH
HEIGHTS BEGINNING TO RISE AS HIGH PRESSURE GRADUALLY BUILDS ACROSS
THE WESTERN COUNTIES. PRECIPITABLE VALUES LOWER SIGNIFICANTLY RANGING
FROM 50 TO 60 PERCENT ACROSS THE AREA. A FEW ISOLATED SHOWERS CAN NOT
BE RULED OUT BUT THE COVERAGE WILL BE EVEN LESS THAN TODAY. LEFT ONLY
A 20 PERCENT FROM STARR COUNTY EAST TO THE COAST. PRESSURE GRADIENT
WILL STRENGTHEN ALSO INCREASING THE SOUTHEAST WINDS IN THE AFTERNOON.
HIGH TEMPS WILL REACH THE UPPER 90S AND TRIPLE DIGITS OUT WEST. MONDAY
NIGHT...ANOTHER TROPICAL WAVE APPROACHES THE AREA SURGING DEEP MOIST
AIR INTO THE CWA ONCE AGAIN. 1000 TO 500 MB RH VALUES INCREASE TO 65
PERCENT ESPECIALLY OVER THE GULF WATERS. THEREFORE...LEFT INHERITED
20 PERCENT POP FOR MONDAY NIGHT.

.LONG TERM /TUESDAY THROUGH SATURDAY/...THE MAIN FOCUS WILL BE THE
TROPICAL WAVE IN THE WESTERN CARIBBEAN...ALREADY MOVING ACROSS THE
YUCATAN PENINSULA...WITH THE NORTHERN PART OF THE WAVE EXPECTED TO
ENTER AND TRAVERSE THE BAY OF CAMPECHE ON MONDAY. CONDITIONS OVER
THE BAY OF CAMPECHE WILL FAVOR FURTHER DEVELOPMENT...BUT LONGEVITY
WILL BE AN ISSUE...WITH THE MODELS MOVING WHATEVER DEVELOPS ON THE
BAY OF CAMPECHE INTO THE EASTERN MEXICAN COAST RATHER QUICKLY.
WEATHER RAMIFICATIONS FOR THE CWA WILL DEPEND ON THE MOISTURE THAT
FEEDS NORTH ON THE SOUTHEAST SYNOPTIC SCALE FLOW. USE OF THE NAM WAS
LIMITED AS IT WAS MORE AGGRESSIVE IN INCREASING POPS.

NONETHELESS...UNSETTLED WEATHER WILL RETURN TO THE CWA IN THE LONG
TERM AS DEEP TROPICAL MOISTURE INCREASES. PRECIPITABLE WATER VALUES
WILL CLIMB ABOVE TWO INCHES BY LATE TUESDAY...WHICH WILL SUPPORT A
GOOD CHANCE OF SHOWERS AND THUNDERSTORMS TUESDAY THROUGH LATE WEEK.
THE GFS AND ECMWF WERE BALANCED WITH PERSISTENCE TO YIELD PULSES OF
BETTER THAN 50 PERCENT RAIN CHANCES FOR THE AREA. SLIGHTLY HIGHER
AMOUNTS WERE NOTED OVER THE MARINE AREAS. IN ANY CASE...A FEW DAYS
OF UNSETTLED WEATHER WILL BE IN STORE...WITH AREAL AMOUNTS OF RAIN
FALL LIKELY TO VARY FROM A FEW TENTHS OF AN INCH TO A FEW INCHES
DEPENDING ON WHETHER ANY PARTICULAR SPOT ENDS UP UNDER A HEAVILY
LOADED TROPICAL TOWER.

RAIN CHANCES WILL DECREASE TOWARD NEXT WEEKEND AS THE WAVE MOVES
INLAND AND CONDITIONS RECOVER WITH LOWER...ALBEIT MORE TYPICAL...
MOISTURE LEVELS. THERE WILL BE A GOOD MIX OF CLOUDS AND SUN...BUT
LIKELY A BIT MORE CLOUDS...AND HIGH TEMPS WILL BE HELD DOWN BELOW
NORMAL. DEW POINTS WILL REMAIN IN THE 70S HOWEVER...AND HEAT INDEX
VALUES WILL REMAIN WELL INTO THE 90S OR NEAR THE CENTURY MARK.

&&

.MARINE...
NOW THROUGH MONDAY NIGHT...ABUNDANT MOISTURE ASSOCIATED TO THE
LOW PRESSURE THAT REMAIN ALMOST STATIONARY OVER THE AREA HAS
GRADUALLY LIFTED NORTHEAST TODAY LOWERING THE SHOWER ACTIVITY
ACROSS THE GULF TODAY. NOW...THE SE SWELL HAVE INCREASE SO THERE
IS A STATEMENT FOR MODERATE RISK OR RIP CURRENT ALONG THE BOCA
CHICA BEACH AND THE SPI BEACHES DUE TO THE HOLIDAY WEEKEND
ACTIVITIES. MONDAY...THE AREA OF DEEP MOISTURE EXITS THE AREA
LOWERING THE CHANCE OF SHOWERS AS HIGH PRESSURE BUILDS FROM THE
WEST. THE SEAS REMAIN BETWEEN 2 TO 4 FEET. A TROPICAL WAVE OVER
THE YUCATAN PENINSULA AND CENTRAL AMERICA WILL CONTINUE TO MOVE
WEST AT AROUND 10 KNOTS AND HAS LOW LEVEL CYCLONIC TURNING NOTED
ON VISIBLE SATELLITE OVER BELIZE. THE ENVIRONMENT WILL BE MORE
CONDUCIVE FOR FURTHER DEVELOPMENT ONCE THE SYSTEM MOVES INTO THE
SW GULF OF MEXICO MONDAY. THERE IS MEDIUM CHANCE FOR TROPICAL
DEVELOPMENT AT THIS TIME. THIS WILL LIKELY INCREASE SWELLS
BUILDING SEAS OVER THE GULF WATERS BY LATE MONDAY AFTERNOON. AT
THIS TIME...CONTINUE TO KEEP SEAS UP TO 5 FEET BUT THIS MAY
CHANGE. CONVECTION WILL BE ON THE DECREASE INTO MONDAY WITH LESS
HUMIDITY IN THE AREA BUT PRESSURE GRADIENT WILL BE THE MAIN ISSUE.
SE WINDS WILL PICK UP IN THE AFTERNOON HOURS AND DIMINISH AFTER
SUNSET.

TUESDAY THROUGH THURSDAY...A LOW PRESSURE SYSTEM BREWING IN THE
SOUTHWEST GULF ON TUESDAY WILL PRODUCE UNSETTLED WEATHER WHICH WILL
MOVE NORTH THROUGH THE FORECAST PERIOD. IN ADDITION...THE SYSTEM
WILL INTERACT WITH HIGHER PRESSURE OVER THE NORTHEAST GULF WHICH
WILL TIGHTEN THE PRESSURE GRADIENT AND WILL RESULT IN STRONGER
SOUTHEAST WINDS AND HIGHER SEAS EARLY IN THE PERIOD. SMALL CRAFT
ADVISORY CONDITIONS MAY DEVELOP TUESDAY AS WINDS APPROACH 20
KNOTS...WITH WIND WAVES AND SWELL COMBINING TO BUILD SEAS TO SEVEN
FEET FROM LATE TUESDAY THROUGH WEDNESDAY NIGHT. THE GRADIENT WILL
RELAX A LITTLE AFTER MID WEEK AS THE LOW PRESSURE AREA FILLS AND
MOVES INLAND OVER MEXICO...ALLOWING WINDS TO DECREASE TO MDT...BUT
WAVE HEIGHTS DUE TO SWELL WILL REMAIN ELEVATED THROUGH WEDNESDAY
NIGHT OR THURSDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  80  92  80  90 /  20  20  20  40
BROWNSVILLE          78  94  78  91 /  20  20  20  40
HARLINGEN            78  96  77  92 /  20  20  20  50
MCALLEN              80  98  79  94 /  10  20  10  60
RIO GRANDE CITY      79  99  79  95 /  10  10  10  30
SOUTH PADRE ISLAND   81  89  80  88 /  20  20  20  40

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK UNTIL 1 AM CDT MONDAY FOR TXZ251-256-257.

GM...NONE.
&&

$$

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