Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 301807 AAC
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
107 PM CDT SAT MAY 30 2015

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

&&

.AVIATION...THE MAIN IMPACT FOR THIS TAF CYCLE WILL BE THE ONGOING
CONVECTION NEAR EAGLE PASS. THIS THUNDERSTORM COMPLEX WILL MOVE
SOUTHEAST THROUGH THIS AFTERNOON. HAVE ADDED A TEMPO GROUP FOR
TSRA/MVFR CONDITIONS AT ALL RIO GRANDE VALLEY AIRPORTS BASED ON
CURRENT RADAR TRENDS. OTHERWISE...VFR CONDITIONS AND MODERATE
SOUTHEAST WINDS WILL PREVAIL THIS AFTERNOON BEFORE THE SHOWERS AND
THUNDERSTORMS ARRIVE. MVFR CONDITIONS EXPECTED TO AFTER 08Z DUE TO
LOW CEILINGS AND LIGHT FOG FROM RECENT RAINS.

&&

.PREV DISCUSSION... /ISSUED 951 AM CDT SAT MAY 30 2015/

DISCUSSION...LATEST SATELLITE IMAGERY SHOWS AN ONGOING MCS ACROSS
WEST TEXAS...JUST NORTH OF THE BIG BEND REGION. THIS COMPLEX MAY
HOLD TOGETHER AND REACH PORTIONS OF THE DEEP SOUTH TEXAS LATER
THIS AFTERNOON. IF THIS FEATURE DOES NOT HOLD TOGETHER...THE OUTFLOW
BOUNDARIES FROM THIS FEATURE COMBINED WITH ABUNDANT MOISTURE
/PRECIPITABLE WATER VALUE OF 1.63 INCHES PER BRO 12Z
SOUNDING/ AND DAYTIME HEATING WILL SUPPORT SOME AFTERNOON
CONVECTION. A WEAK COLD FRONT ACROSS CENTRAL TEXAS WILL DRIFT
SOUTH TONIGHT COMBINED WITH SOME UPPER LEVEL SUPPORT WILL MAINTAIN
A CHANCE OF SHOWERS AND THUNDERSTORMS TONIGHT. THE GROUND REMAINS
NEARLY SATURATED ACROSS MOST OF DEEP SOUTH TEXAS FROM THE RAINFALL
OF THE PAST COUPLE OF WEEKS...THE POTENTIAL FOR FLASH FLOODING
EXISTS WITH HEAVY RAINFALL. AVERAGE RAINFALL AMOUNTS OF 1 TO 3
INCHES...WITH HIGHER AMOUNTS POSSIBLE...ACROSS DEEP SOUTH TEXAS
LATE THIS AFTERNOON THROUGH EARLY SUNDAY MORNING. HAVE DECIDED TO
ISSUE A FLASH FLOOD WATCH FOR ALL OF DEEP SOUTH TEXAS FROM 3 PM
THIS AFTERNOON THROUGH TONIGHT. MADE A FEW ADJUSTMENTS TO
POPS/QPF/WX GRIDS FOR TODAY AND TONIGHT. NO OTHER CHANGES NEEDED.

THANKS FOR THE COORDINATION NESDIS.

PREV DISCUSSION... /ISSUED 457 AM CDT SAT MAY 30 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...SCT TO BKN LOW CLOUDS SHOULD DEVELOP TODAY...WITH VFR
CEILINGS AND LIGHT TO MODERATE SOUTHEAST WINDS. A FEW SHOWERS
AND/OR THUNDERSTORMS MAY DEVELOP AROUND THE AREA TODAY...BUT WILL
NOT INCLUDE EXPLICIT MENTION IN THE TAFS FOR NOW DUE TO SPOTTY
COVERAGE.

PREV DISCUSSION... /ISSUED 338 AM CDT SAT MAY 30 2015/

SHORT TERM /NOW THROUGH SUNDAY/...A MOSTLY CLEAR NIGHT WILL
TURN INTO A SEASONAL WEATHER DAY OVER DEEP SOUTH TEXAS AND THE
RGV. LOW CU WILL DEVELOP DURING THE DAY ON LIGHT TO MODERATE
SOUTHEAST WINDS. A COLD FRONT WILL EDGE SOUTH INTO CENTRAL
TEXAS...FIRING OFF TSTMS ALONG THE BOUNDARY...BUT MORE SO OVER
WEST TEXAS. A SQUALL LINE IS MOVING OUT AHEAD OF THE FRONT THIS
MORNING...AND A REMNANT BOUNDARY COULD REACH THE NORTHERN
RANCHLANDS BY AROUND NOON. THE FRONT ITSELF MAY LOSE DEFINITION
OVER SOUTH TEXAS BY TONIGHT...BUT ITS PRESENCE WILL BE MADE KNOWN
VIA ONGOING CONVECTION WEST OF THE RIO GRANDE PLAINS. ADDITIONAL
TSTMS MAY ACTIVATE OVER THE MEXICAN MOUNTAINS. HIGH TEMPS WILL
RANGE FROM THE LOWER TO MID 80S ALONG THE COAST TO THE LOWER 90S
INLAND WITH A MIX OF CLOUDS AND SUN WITH LIGHT TO MODERATE
SOUTHEAST WINDS.

SATURDAY NIGHT...TONIGHT...THE REMNANTS OF THE FRONT WILL PUSH OUT
INTO THE NORTHWEST GULF ON THE EAST AND WILL CONTINUE TO SUPPORT
CONVECTION UPSTREAM OVER THE RIO GRANDE PLAINS. THIS CONVECTION WILL
MAINLY DIE OUT BEFORE HAVING ANY BIG IMPACT ON THE CWA BUT A FEW
TSTMS COULD MAKE IT INTO WESTERN SECTIONS. LOW TEMPS WILL BE IN THE
LOWER TO MID 70S WITH LIGHT ONSHORE WINDS.

MORE INFLUENCE SUNDAY FROM THE STALLED FRONT OVER THE MIDDLE TEXAS
COAST AS MOISTURE POOLS OVER DEEP SOUTH TEXAS...THOUGH THE FORECAST
SOUNDING SHOWS PWAT STAYING AROUND 1.5 INCHES. RAIN CHANCES WILL
INCREASE INTO THE CHANCE CATEGORY SUNDAY NONETHELESS...DESTABILIZED
BY THE NEARBY BOUNDARY. SLIGHTLY DRIER AIR WILL MOVE SOUTH INTO THE
CWA ON MONDAY HOWEVER. HIGH TEMPS WILL MODERATE A BIT...DOWN INTO
THE MID 80S... WITH LIGHT EAST WINDS.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...UPPER TROF WILL BE
SLOWLY PROGRESSING EASTWARD TOWARDS THE SOUTHEAST CONUS AS RIDGING
BUILDS ACROSS THE WESTERN CONUS. GFS/ECMWF IN BETTER AGREEMENT
THAN 12 HOURS AGO WITH BOTH MODELS NOW DEVELOPING A CLOSED LOW
OVER THE NORTH CENTRAL GULF OF MEXICO THEN PROGRESSING IT
NORTHEASTWARD TOWARD GEORGIA BY FRIDAY. MID LEVEL HIGH PRESSURE
BUILDS ACROSS TEXAS INTO THE SOUTHERN PLAINS. MID LEVEL DRY AIR
BUILDS IN FOR MONDAY AND EXPANDS THROUGH THE REST OF THE PERIOD.
WITH PWATS LOWER AND AN INCREASE IN DRY AIR...MODELS HAVE BEEN
TRENDING LOWER ON THE PRECIPITATION CHANCES. THEREFORE...HARD TO
ARGUE ANY MORE THAN SLIGHT CHANCE FOR SHOWERS/STORMS IN THE
EXTENDED. FAVORED SEA BREEZE ACTIVITY LOCATIONS /EAST OF I 69C TO
THE COAST/ WHERE SLIGHT CHANCE POPS ARE LOCATED. HIGH TEMPERATURES
WILL BE IN THE UPPER 80S TO AROUND 90 IN THE COASTAL COUNTIES TO
THE LOWER 90S ACROSS THE WESTERN SECTIONS.

MARINE /NOW THROUGH SUNDAY/...BROAD HIGH PRESSURE EXTENDING
ACROSS THE NORTH GULF WILL RESULT IN A WEAK PRESSURE GRADIENT
LOCALLY...WITH LIGHT TO MODERATE EAST TO SOUTHEAST WINDS AND LOW
TO MODERATE SEAS. A FEW SHOWERS MAY MOVE NORTH ALONG THE COAST
THIS AFTERNOON THROUGH SUNDAY.

SUNDAY NIGHT THROUGH WEDNESDAY...LIGHT NORTHEAST WINDS WILL
PREVAIL ACROSS THE COASTAL WATERS SUNDAY NIGHT WITH WEAK SURFACE
HIGH PRESSURE BUILDING INTO THE NORTHWEST GULF OF MEXICO. LIGHT
AND VARIABLE WINDS WILL PREVAIL ACROSS THE COASTAL WATERS MONDAY
AS THE PRESSURE GRADIENT REMAINS WEAK ACROSS THE WESTERN GULF.
LIGHT SOUTHEAST WINDS SHOULD PREVAIL ACROSS THE LOWER TEXAS COAST
TUESDAY AND WEDNESDAY AS A SURFACE TROUGH OF LOW PRESSURE MOVES
INTO NORTHWEST TEXAS. SEAS WILL BE 2 FEET OR LESS.

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...FLASH FLOOD WATCH THROUGH SUNDAY MORNING FOR TXZ248>257.

GM...NONE.
&&

$$

THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTP://WEATHER.GOV/RGV

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