Area Forecast Discussion
Issued by NWS Brownsville, TX

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS64 KBRO 280553 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1253 AM CDT SUN JUN 28 2015

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

&&

.AVIATION...A FEW PASSING LOW CLOUDS WITH SCATTERED HIGH LEVEL
CLOUDINESS PREVAILS ACROSS DEEP SOUTH TEXAS AND THE RIO GRANDE
VALLEY EARLY THIS MORNING. VFR CONDITIONS EXPECTED ACROSS THE AREA
FOR THE NEXT 24 HOURS. LIGHT WINDS OVERNIGHT WILL BECOME BREEZY
BY LATE MORNING WITH GUSTS AROUND 20 KNOTS IN THE AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 630 PM CDT SAT JUN 27 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...ISOLATED CONVECTION HAS CONTINUED TO DEVELOP OVER DEEP
SOUTH TEXAS AND THE RIO GRANDE VALLEY...BUT NOWHERE NEAR THE MAJOR
AERODROMES...WHERE VFR IS FIRMLY IN PLACE. VFR WILL CONTINUE FOR
THE OVERNIGHT HOURS WITH LIGHT WINDS AND CLEAR SKIES. TOMORROW...
SURFACE WINDS WILL BECOME BREEZY WITH A SCATTERED VFR CEILING.

PREV DISCUSSION... /ISSUED 322 PM CDT SAT JUN 27 2015/

SHORT TERM  /TONIGHT THROUGH SUNDAY NIGHT/...LATEST WATER VAPOR IMAGERY
AND 250 MB WINDS SHOWS THE CWA IN BETWEEN AN UPPER LOW OVER THE GULF
OF MX AND BROAD HIGH PRESSURE ACROSS THE W. THIS HAS CREATED AN AREA
OF DIFFLUENCE ALOFT RIGHT ALONG THE LOWER VALLEY WITH SUFFICIENT
MOISTURE TO WORK WITH TO ENHANCE A FEW ISOLATED SHOWERS ALONG THE
COAST. MEANWHILE...EVERYWHERE WEST OF HIGHWAY 77 NORTHERLY FLOW
ALOFT WITH SUBSIDENCE WILL LIMIT THE PRECIPITATION POTENTIAL TOWARDS
THE WESTERN COUNTIES. AS THE LOW SLOWLY DRIFTS WEST TODAY INTO
TONIGHT HIGHER VALUES OF MOISTURE MOVE INTO THE CWA DURING THE SHORT
TERM PERIOD AND GRADUALLY INCREASE SHOWERS AND THUNDERSTORMS SAT
NIGHT INTO SUN. LOW TEMPERATURES TONIGHT WILL REMAIN IN THE MID TO
UPPER 70S AND A REPEAT INTO SUNDAY NIGHT WITH A FEW DEGREES LOWER.
TOWARDS THE NORTH...AN UPPER TROUGH DIGS SOUTHWARD ACROSS THE SE
PLAINS AND PUSHES A BOUNDARY ACROSS S TEXAS...BUT THIS BOUNDARY
STALLS TO THE NORTH OF THE CWA. A FEW SHOWERS AND STORMS WILL
ENHANCE WITH THIS BOUNDARY AND COULD POTENTIALLY MAKE ITS WAY INLAND
INTO THE CWA TONIGHT OVER THE NORTHERN COUNTIES. INCREASE POPS
CLOSER TO WHAT GUIDANCE TRENDS. SOUTHEASTERLY FLOW WILL PREVAIL
BECOMING LIGHT OVERNIGHT. INTO SUNDAY AS THE LOW SHIFTS SLIGHTLY
WESTWWARD THE CHANCES OF RAIN INCREASE NEAR THE COAST AND WLL BE
ENHANCE WITH SEA BREEZE IN THE AFTERNOON. POPS REFLECT HIGH POPS
NEAR RIGHT ALONG THE COAST WHERE THE HIGHER CHANCES WILL BE DUE TO
THE SEA BREEZE. HIGH TEMPERATURES WILL RANGE BETWEEN THE MID TO
UPPER 90S.

LONG TERM /MONDAY THROUGH SATURDAY/...THOUGH JULY ON THE WHOLE
SHOULD BEGIN TO TURN DRIER AND HOTTER...THE TURN OF THE CALENDAR
FROM JUNE TO JULY IN 2015 PUTS A HOLD ON THE PATTERN THAT
TYPICALLY BRINGS IT WHICH FEATURES UPPER LEVEL HIGH PRESSURE
ACROSS NORTHERN MEXICO THROUGH CENTRAL/WEST TEXAS THAT SPREADS
INTO THE WESTERN GULF AND SUPPRESSES MUCH OF THE TROPICAL MOISTURE
INTO MEXICO MAINLY FROM TAMPICO SOUTHWARD. THAT `HOLD` IS A RETURN
OF A SLOW MOVING...ALBEIT WEAK...*TROUGH* THAT SETTLES IN ACROSS
NORTHEAST MEXICO AND DEEP SOUTH TEXAS FOR MUCH OF THE PERIOD.
DEEPER MOISTURE WILL BRING MORE OVERALL CLOUDINESS THOUGH MUCH
WILL BE DETERMINED BY CONVECTION AND `BLOW OFF` WHICH SHOWED UP
FOR A TIME EARLIER THIS WEEK...MAINLY MONDAY THROUGH WEDNESDAY.
FOR PLANNING PURPOSES...STILL A LOT OF UNCERTAINTY FOR THE FOURTH
OF JULY BUT DIURNAL CLIMATOLOGY EVEN IN A WETTER THAN AVERAGE
PATTERN SUGGESTS EVENING ACTIVITIES SHOULD BE ABLE TO GO OFF FINE.
STAY TUNED.

FOR THE SENSIBLE WEATHER...GFS/ECMWF TEND TO FAVOR MAINLY FAIR
WEATHER CUMULUS OUTSIDE OF ANY ISOLATED CONVECTION WHICH WOULD
INITIALLY FAVOR THE COAST AND GULF WATERS THEN SHIFT INTO THE MID
VALLEY AND RANCHLANDS BY AFTERNOON. SHOULD BE ENOUGH FILTERED
SUNSHINE TO PUSH TEMPERATURES CLOSE TO SEASONAL NORMALS...MID TO
UPPER 90S INLAND AND LOWER 90S NEAR THE COAST.

BY TUESDAY...THE REGION IS ON THE BACKSIDE OF THE TROUGH AND
SHOULD BEGIN TO SEE MORE COVERAGE OF ISOLATED TO SCATTERED STORMS.
TIME/HEIGHT CROSS SECTIONS FAVOR THE LOWER AND PERHAPS MID VALLEY
WITH THE FAVORED LATE NIGHT/EARLY MORNING START IN THE
GULF...MOVING ONSHORE AT OR JUST AFTER DAYBREAK BEFORE SHIFTING
INLAND. HOW MUCH `GOES` INLAND REMAINS IN QUESTION AND THERE ARE
BIG DIFFERENCES AMONG THE MODELS...SO FOR NOW NUDGED UP TO 40
PERCENT AND WILL LET LATER SHIFTS HONE IN ON THE DETAILS.

MORE OF THE SAME FOR WEDNESDAY AND THURSDAY WITH PLENTY OF
MOISTURE AT DIFFERENT ATMOSPHERIC LAYERS BUT THE BIG PICTURE OF
REMNANT SOUTHERLY FLOW ON THE BACKSIDE OF THE 500 MB TROUGH
CONTINUING. IN GENERAL...THIS FAVORS A CONTINUED DIURNAL PATTERN
OF MAINLY OVERNIGHT/MORNING ACTIVITY OVER THE GULF...MORNING/EARLY
AFTERNOON ACTIVITY ALONG AND EAST OF U.S. 77...AND AFTERNOON INTO
EARLY EVENING ACTIVITY ELSEWHERE. EXACTLY WHICH DAY WILL BE
WETTEST REMAINS TO BE SEEN. MODEL STATISTICAL GUIDANCE FOCUSES ON
WEDNESDAY BUT RAW DATA SUGGEST THURSDAY COULD BE THE DAY AS WELL.
A FINAL NUGGET OF POSSIBLE INTEREST IS THE DEVELOPMENT OF A 35-40
KNOT SOUTHERLY 850 MB JET OVER THE RIO GRANDE PLAINS
/STARR...ZAPATA...JIM HOGG/...WHICH COULD FOCUS SOME HEAVY RAINS
ALONG THE RIO GRANDE AND OUT TOWARD THE SIERRA MADRE...SOMETHING
TO KEEP AN EYE ON AS THE WEEK PROGRESSES.

TO CLOSE THE WEEK INCLUDING THE BIG FOURTH OF JULY HOLIDAY
WEEKEND...NOT MUCH CHANGE AS THE DRIER UPPER RIDGE IS LOCKED UP
ACROSS THE U.S. FOUR CORNERS...WITH BERMUDA HIGH`S WESTWARD EXTENT
TO THE WESTERN GULF...AND SOUTH TEXAS/NORTHEAST MEXICO SQUEEZED IN
THE TROUGH. THIS SUGGESTS MORE OF THE SAME WHICH WOULD MEAN MORE
DODGE`EM SHOWERS/THUNDERSTORMS ON THE FOURTH ITSELF BUT A GENERAL
BREAK FOR THE MID EVENING FESTIVITIES.

AS FOR POTENTIAL LOCAL FLOODING? ONE CAN NEVER RULE OUT IN LATE
JUNE IN THIS PATTERN ESPECIALLY IF STORMS REPEATEDLY TRACK OVER
THE SAME AREAS AS HAPPENED ON FRIDAY JUNE 20 IN EDINBURG. AT LEAST
THERE`S NO WILDFIRE THREAT FOR THE FIREWORKS PERIOD THIS YEAR.

MARINE...NOW THROUGH SUNDAY NIGHT:
BROAD SURFACE HIGH PRESSURE IS IN CONTROL OVER THE GULF OF
MEXICO. THIS WILL MAINTAIN A SOUTH TO SE FLOW ACROSS THE GULF
WATERS AND THE LAGUNA WITH LIGHT TO MODERATE SE WINDS. AN UPPER
LEVEL LOW OVER THE AREA WITH GREATER AMOUNT OF RH IN THE GULF WILL
MOVE WEST TOWARDS THE LOWER TEXAS GULF COAST ENHANCING SHOWERS AND
THUNDERSTORMS TODAY AND TONIGHT. SEAS WILL ALSO REMAIN LOW RANGING
FROM 2 TO 4 FEET AT THE MOST. DUE TO THE INCREASE IN SE
WINDS...SCEC CONTINUES IN THE LAGUNA TODAY. THE REMAINDER OF THE
SHORT TERM NO SCEC OR SCA EXPECTED.

MONDAY THROUGH THURSDAY: MAINLY ISOLATED OVERNIGHT/MORNING
SHOWERS AND STORMS MONDAY WILL BECOME MORE SCATTERED AT THE SAME
TIMES TUESDAY THROUGH THURSDAY...AND ACTIVITY LIKELY TO CONTINUE
FOR MOST WATERS INTO THE AFTERNOON BEYOND 5-10 NM FROM THE SHORE.
AS FOR WIND? A GENERAL 15 KNOT PATTERN WILL CONTINUE...WITH SOME
INCREASE TOWARD THE END OF THE PERIOD AND HIGHLY DEPENDENT ON HOW
MUCH OF THE LOW LEVEL JET CAN MIX DOWN ESPECIALLY AT NIGHT OVER
THE GULF. FOR NOW...HOLDING AT CAUTION LEVELS AND KEEPING SEAS NO
HIGHER THAN 5 FEET ON AVERAGE MAINLY WEDNESDAY AND THURSDAY.

BOTTOM LINE? OVERALL BOATING/FISHING CONDITIONS WON`T BE OPTIMAL
WITH MONDAY BEING THE BETTER DAY OF THE PERIOD.

&&

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

$$

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

63


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.