Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 202347 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
647 PM CDT WED AUG 20 2014

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

.AVIATION...WINDS ARE BEGINNING TO DIMINISH ACROSS DEEP SOUTH
TEXAS AND WITHIN THE RIO GRANDE VALLEY AS SKIES CLEAR FROM EAST
TO WEST ALONG THE SEABREEZE BOUNDARY. A FEW CLOUDS AROUND 2500
OR 3000 FEET ARE EXPECTED TONIGHT WITH LIGHT WINDS IN PLACE.
TOMORROW...VFR WILL PREVAIL WITH BREEZY WINDS AND RISING CLOUD
DECKS.
&&

.PREV DISCUSSION... /ISSUED 246 PM CDT WED AUG 20 2014/

SHORT TERM /NOW THROUGH THURSDAY NIGHT...HIGH PRESSURE CONTINUES TO
INTERACT WITH LOW PRESSURE OVER THE GULF WATERS KEEPING A BREEZY
SOUTHEAST FLOW FOR THE REST OF THIS AFTERNOON ACROSS THE CWA. LATEST
WATER VAPOR AND SAT IMAGERY SHOWS WEAK TROPICAL LOW IS ENHANCING
ISOLATED SHOWERS OVER THE GULF WATERS TODAY. THIS ACTIVITY WILL
CONTINUE ALONG THE COAST AND THE GULF WATERS WHERE PWATS OR BETTER
MOISTURE IS AVAILABLE TO SUPPORT CONVECTION. THE CHANCES OF RAIN
LOWER FOR THE REMAINDER OF THE SHORT TERM AS UPPER LEVEL HIGH
RETROGRADES WESTWARD AND INTERACT WITH UPPER LEVEL TROUGH DIGGING
SOUTH ACROSS THE PACIFIC NORTHWEST. ABUNDANT DRY AIR WILL MOVE INTO
THE AREA WITH 1000 TO 500 MB RH VALUES LOWERING TO 30 PERCENT
LIMITING ANY SHOWER ACTIVITY THURSDAY. WITH LESS CLOUD COVER...HIGH
TEMPS WILL CLIMB INTO THE TRIPLE DIGITS AGAIN SO DECIDED TO INCREASE
TEMPS A DEGREE OR TWO WEST OF HWY 281. LOW TEMPERATURES WILL REMAIN
IN THE MID TO UPPER 70S ACROSS THE AREA WITH LOWER WINDS BETWEEN 10
TO 15 MPH.

LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
WARM AND HUMID THROUGHOUT...BREEZY/WINDY FRIDAY...PATTERN SHIFTS TO SPOTTY
SHOWERS AND LIGHTER WINDS FRIDAY THROUGH WEDNESDAY BUT AVAILABLE
MOISTURE MARGINAL.

THURSDAY NIGHT INTO FRIDAY MID LEVEL RIDGING OVER THE LOWER
MISSISSIPPI VALLEY WILL BE IN THE PROCESS OF WEAKENING SLIGHTLY AS
IT IS INFLUENCED BY ADVANCING TROUGHING/JET MAXES OVER THE
SOUTHWESTERN US. THE SURFACE REFLECTION...IN THE FORM OF A RIDGE
CENTERED OVER THE NORTH CENTRAL GULF OF MEXICO...AND WEAK LEE AND
THERMAL TROUGHING TO OUR WEST SHOULD HOWEVER GENERALLY STAY IN PLACE
FOR FRIDAY. THIS SHOULD RESULT IN BREEZY TO WINDY CONDITIONS ACROSS
THE AREA WITH HOT TEMPERATURES. SOUTHWESTERLY WINDS ALOFT WILL HELP
LIMIT CONVECTIVE POTENTIAL AS WILL THE STRONG SOUTHEASTERLY FLOW
THAT SHOULD KEEP THE SEABREEZE BOUNDARY FROM GETTING A STRONGHOLD.

SATURDAY THE MID LEVEL RIDGE WILL HAVE RETREATED A LITTLE FURTHER
NORTH AND THE SURFACE RIDGE WILL BECOME MORE ELONGATED OVER THE
NORTHERN GULF COAST WHICH WILL RESULT IN A LONG FETCH OF EASTERLY
WINDS ACROSS BASICALLY THE ENTIRE GULF. THIS WILL RESULT IN MORE
MODERATE ONSHORE FLOW...WHICH WILL PROBABLY PULL TEMPERATURES DOWN A
BIT AND MAY ALLOW ENOUGH OF A SEABREEZE BOUNDARY TO GET SETUP TO
SPARK A FEW SHOWERS OR STORMS AND KEPT THE SLIGHT CHANCE IN ALONG
THE 77 CORRIDOR. 850-700MB MOISTURE REMAINS PRETTY MARGINAL HOWEVER
AND THIS SHOULD KEEP COVERAGE AND INTENSITY LIMITED. THE LONG
EASTERLY FETCH MAY GENERATE A LITTLE BIT OF LONG PERIOD SWELL BUT
THE DURATION AND INTENSITY APPEAR TOO WEAK FOR COASTAL RUNUP/HIGHER
THAN NORMAL TIDES.

SUNDAY FEATURES A LITTLE BIT BETTER AVAILABLE LOW LEVEL MOISTURE
WITH MODERATE EAST TO SOUTHEASTERLY WINDS AS THE ELONGATED LOW LEVEL
RIDGING BECOMES A BIT WEAKER. GFS/ECMWF BOTH SHOW A SYNOPTIC PATTERN
FAVORABLE FOR A STRONGER SEABREEZE BOUNDARY AND MARGINAL
TEMPERATURE/MOISTURE PROFILES FOR A FEW SHOWERS AND STORMS AND
CONTINUED THE SLIGHTLY LARGER AREA OF SLIGHT CHANCE SHOWERS/STORMS
TO ENCOMPASS MOST OF THE VALLEY. AGAIN MOISTURE AND THE THERMAL
PROFILE IS MARGINAL AND COVERAGE AND INTENSITY LOOK LOW AT THE
MOMENT.

MONDAY A WEAK UPPER LEVEL TUTT LIKE LOW APPEARS ALONG THE WESTERN
GULF COAST OF MEXICO. THIS APPEARS TO BE PARTIALLY INFLUENCED BY THE
OUTFLOW OF EPAC CYCLONE LOWELL AND A YET TO FORM STORM IN THE
EASTERN PACIFIC. THAT FEATURE DOES NOT APPEAR TO HAVE MUCH INFLUENCE
ON OUR SENSIBLE WEATHER HOWEVER BUT SLIGHTLY DEEPER AND RICHER LOW
LEVEL MOISTURE MAY WORK WITH MODERATE EAST TO SOUTHEAST WINDS TO
ACTIVATE THE SEABREEZE BOUNDARY AND CONTINUED A SLIGHT CHANCE OF
SHOWERS/STORMS IN THE AFTERNOON OVER A SIMILAR AREA TO MONDAY.

TUESDAY INTO WEDNESDAY SEE LITTLE LOCAL CHANGE IN THE PATTERN WITH
RIDGING FAILING TO BECOME REESTABLISHED OVER THE GULF OF
MEXICO...BUT NO REAL SURGE OF MOISTURE TO HELP TAKE FULL ADVANTAGE
OF THIS IN TERMS OF RAIN AND THUNDER CHANCES. FAIRLY SIGNIFICANT
DIFFERENCE DEVELOP BY WEDNESDAY IN TERMS OF THE HANDLING OF A MID
CONTINENT TROUGH THOUGH THAT WILL LIKELY PLAY A ROLE BY WEDNESDAY.
THE GFS SHOWS A STRONGER AND MORE AMPLIFIED OPEN WAVE OVER THE
PLAINS WHERE THE ECMWF KEEPS A MORE CLOSED FEATURE OVER THE EASTERN
ROCKIES. THE GFS SOLUTION WOULD PROBABLY INCREASE WINDS AGAIN AND
TEMPORARILY CUT OFF ANY TAP OF MOISTURE BUT LIKELY NOT BY
WEDNESDAY SO KEPT THE SLIGHT CHANCE OF AFTERNOON SHOWERS AND STORMS
IN THE FORECAST. /68-JGG/

MARINE...
NOW THROUGH THURSDAY NIGHT...
SOUTHEAST WINDS WILL PREVAIL THROUGH THE SHORT TERM PERIOD WITH
CHANCE OF SHOWERS INCREASING OVER THE GULF WATERS THE REMAINDER OF
THE AFTERNOON. SMALL CRAFT ADVISORY IS IN EFFECT OVER THE LAGUNA
MADRE THROUGH THE EVENING. CONDITIONS IMPROVE TONIGHT BUT WINDS
PICK UP AGAIN INTO THURSDAY WITH POSSIBLE SCA CONDITIONS FOR THE
AFTERNOON HOURS OVER THE LAGUNA AND SCEC OVER THE NEARSHORE. THIS
IS DUE TO THE PRESSURE GRADIENT INCREASING ONCE AGAIN. SEAS WILL
REMAIN BETWEEN 3 TO 5 FEET OFFSHORE.

THURSDAY NIGHT THROUGH MONDAY...
ANOTHER DAY OF STRONGER SOUTHEAST WINDS IS FORECAST ON
FRIDAY...ALTHOUGH WIND SPEEDS LOOK TO BE A LITTLE LOWER THAN MOST OF
THE PREVIOUS WEEK. SMALL CRAFT ADVISORIES MAY BE NEEDED ON FRIDAY.
OVERALL MARINE CONDITIONS SHOULD BEGIN TO IMPROVE SATURDAY MORNING
THROUGH THE REST OF THE WEEKEND AS WINDS BECOME MORE MODERATE OUT OF
THE EAST AND EAST TO SOUTHEAST. SEAS SHOULD FALL FROM MODERATE TO
LOW BUT AT LEAST SOME LONGER PERIOD SWELL IS POSSIBLE ON SATURDAY AS
AN EASTERLY FETCH DEVELOPS BEFORE BECOMING MORE LOCAL ON SATURDAY
NIGHT INTO SUNDAY.
&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...SMALL CRAFT ADVISORY FOR WINDS UNTIL 8 PM CDT THIS EVENING FOR
     GMZ130-132-135.
&&

$$

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