Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 302350 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
650 PM CDT TUE JUN 30 2015

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

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
SOME MID TO HIGH LEVEL CLOUDS ACROSS THE CWA EARLY THIS EVENING.
CEILINGS WERE NEAR 4200FT AT KT65. EXPECT MVFR CONDITIONS TO
DEVELOP LATE TONIGHT INTO EARLY WEDNESDAY MORNING AS CONVECTION
DEVELOPS ACROSS PORTIONS OF THE RIO GRANDE VALLEY AS A 500MB
LOW/INVERTED TROUGH ALONG THE LOWER/MIDDLE TX COAST CONTINUES TO
BRING ABUNDANT LOW TO MID LEVEL MOISTURE ACROSS NORTHEAST MEXICO
INTO THE CWA.
&&

.PREV DISCUSSION... /ISSUED 204 PM CDT TUE JUN 30 2015/
SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... CLUSTER OF
SHOWERS AND THUNDERSTORMS HAS WEAKEN OVER THE CENTRAL AND EASTERN
PORTION OF THE CWA WHILE WESTWARD A FEW THUNDERSTORMS ARE
DEVELOPING WITH THE HELP OF DAYTIME HEATING. RAINFALL AMOUNTS
RANGE FROM HALF INCH TO CLOSE TO 1 INCHES WITH ISOLATED SPOT OF 2
TO 3 INCHES OVER WESTERN WILLACY COUNTY. THIS ACTIVITY IS
CURRENTLY MOVING TOWARDS THE NORTH/NORTHWEST AT 15 MPH.

CURRENTLY IN THE UPPER AND MID LEVELS AROUND 500 MB HEIGHT RIDGE HAS
EXPANDED ACROSS THE WESTERN AND CENTRAL PORTION OF THE CONUS WHILE A
TROUGH DOMINATES THE EAST. LATEST WATER VAPOR IMAGERY SHOWS VERY
COLD CLOUD TOPS WITH ABUNDANT DEEP LAYER MOISTURE OVER THE WESTERN
GULF COAST AT THIS TIME. THE KBRO 12Z SOUNDING SHOWS AN INCREASE OF
1.92 INCHES OF PRECIPITABLE WATER WITH SURFACE DEWPOINTS RANGING
BETWEEN 75 TO 73 DEGREES AND A VERY DEEP SOUTHEASTERLY FLOW CLOSE TO
500 MB. WEAK LOW PRESSURE OVER MEXICO ASIDE TO THE ABUNDANT MOISTURE
COMING FROM THE GULF IS PROVIDING ENOUGH INSTABILITY IN THE AREA TO
ENHANCE MORE STREAMER SHOWERS POSSIBLE LATE THIS AFTERNOON AND
CONTINUE INTO TONIGHT MAINLY FAVORING LOCATIONS ALONG THE RIO
GRANDE. DUE TO THE ABUNDANT CLOUD COVER ACROSS THE AREA...LOW
TEMPERATURES WILL REMAIN IN THE LOW TO MID 70S ACROSS MUCH OF THE
CWA AND NEAR 80S ALONG THE COAST TONIGHT.

AFTER MIDNIGHT...ANOTHER PLUME OF MOISTURE MAKES ITS WAY INLAND WITH
RH VALUES IN THE 1000 TO 500 MB 80 PERCENT MOVING ACROSS THE CWA.
THIS WILL ENHANCE A MORE ACTIVE PATTERN EARLY WEDNESDAY MORNING WITH
OCCASIONAL TO FREQUENT LIGHTNING AND MORE MODERATE TO HEAVY
RAINFALL. LEAN TOWARDS THE HIGHER POPS FOR WEDNESDAY AFTERNOON AS
THAT WAVE MOVES THROUGH THE DAY. AS THE SAME PATTERN CONTINUES...THE
HIGH TEMPERATURES REMAIN NEAR NORMAL ACROSS THE AREA. SLIGHTLY DRIER
AIR MOVES INLAND WEDNESDAY NIGHT WHICH WILL DIMINISH THE CHANCE OF
SHOWERS BUT A FEW ISOLATED SHOWERS/STREAMER WITH LIGHT TO MODERATE
RAIN WILL BE POSSIBLE THROUGH EARLY THURSDAY MORNING. LOW
TEMPERATURES WEDNESDAY NIGHT REMAIN IN THE MID 70S ACROSS THE CWA.

LONG TERM /THURSDAY THROUGH TUESDAY/...
MID AND UPPER LEVEL FEATURES CONTINUE TO OPPOSE ONE ANOTHER...AND
ARE NOT EXPECTED TO BE A SIGNIFICANT FACTOR IN THE OVERALL
FORECAST THROUGH THE LONG TERM PERIOD. THE MAIN PLAYER LOCALLY FOR
THE PERIOD WILL BE GULF MOISTURE. THE RAINFALL FORECAST WILL
HINGE ON HOW MUCH MOISTURE IS AVAILABLE EACH DAY DURING PEAK
HEATING. CURRENT MOISTURE POOL WILL BE SWEEPING NORTHWARD ON
THURSDAY...GRADUALLY DECREASING THROUGH LATE WEEK. THERE MAY BE
ENOUGH MOISTURE AROUND ON THURSDAY FOR SHOWERS TO MOVE
INLAND...BUT THEY WILL BE ISOLATED IN NATURE. EVEN LESS MOISTURE
ON FRIDAY WILL LIMIT THE SEABREEZE TO THE IMMEDIATE COAST...WITH A
DRIER DAY FARTHER INLAND. MODELS SHOW A BETTER PLUME IN STORE FOR
SATURDAY AND SUNDAY...BUT NOT EXPECTING A COMPLETE WASHOUT OF THE
HOLIDAY WEEKEND...ALTHOUGH A FEW SITES MIGHT SEE SOME EVENING
NATURAL FIREWORKS. CURRENT LONG RANGE MODELS SHOW THAT MOISTURE
DIMINISHES FURTHER FOR EARLY NEXT WEEK...WITH A CONTINUED DOWNWARD
TREND OF POP CHANCES THROUGH THE MIDDLE OF NEXT WEEK.

MARINE...
NOW THROUGH WEDNESDAY NIGHT...HIGH PRESSURE OVER THE GULF WILL
REMAIN IN CONTROL THROUGH THE SHORT TERM PERIOD KEEPING THE
SOUTHEAST FLOW ACROSS THE GULF WATERS. THE MAIN ISSUES THROUGH THE
PERIOD WILL BE ANOTHER ROUND OF TROPICAL MOISTURE COMING IN EARLY
WEDNESDAY MORNING AND CONTINUING THROUGH THE DAY WITH A CHANCE OF
SHOWERS AND THUNDERSTORMS ACROSS THE GULF WATERS. SEAS WILL REMAIN
BETWEEN 3 TO 5 FEET.

THURSDAY THROUGH SUNDAY...MINIMAL FLUCTUATION IN THE LONGER TERM
MARINE FORECAST AS HIGH PRESSURE DOMINATES THE NORTHERN GULF.
SOUTHEAST WINDS WILL GENERALLY RUN 10 TO 15 KNOTS...WITH BRIEF
HIGHER GUSTS AT TIMES. SEAS STICK TO THE 3 TO 5 FOOT RANGE THROUGH
THE WEEKEND...RUNNING A 5 TO 6 SECOND PERIOD THROUGHOUT.
&&

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

$$

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