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000
FXUS64 KBRO 151141 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
641 AM CDT WED MAY 15 2013

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

.AVIATION...KBRO RADAR SHOWS SHOWERS AND THUNDERSTORMS MOVING
THROUGH THE RANCHLANDS FROM FALFURRIAS SOUTHWARD TO THE MIDDLE
VALLEY AND THIS AREA OF PRECIPITATION IS MOVING EASTWARD. WILL
CONTINUE TO HAVE SHOWERS AND THUNDERSTORMS DEVELOP THIS MORNING WITH
PRECIPITATION ENDING THIS AFTERNOON FROM WEST TO EAST. MVFR CIGS
WITH BRIEF IFR AT TIMES IN SHOWERS WILL BE THE RULE TODAY AS LOW
LEVEL MOISTURE ADVECTS INTO THE AREA ON INCREASING SOUTHEASTERLY
WINDS. GUSTY WINDS EXPECTED BY MID MORNING WITH GUSTS TO 30 KNOTS
POSSIBLE IN THE AFTERNOON HOURS. CIGS LOWER OVERNIGHT APPROACHING IFR
BY MIDNIGHT.
&&

.PREV DISCUSSION... /ISSUED 346 AM CDT WED MAY 15 2013/
SHORT TERM.../TODAY THROUGH THURSDAY/...H5 LOW THAT HAS BEEN
HANGING OUT TO OUR WEST IN NORTHERN MEXICO AND BAJA CALIFORNIA IS
ON THE MOVE TO THE NORTHEAST THIS MORNING AS SHORTWAVE TROUGH OVER
CALIFORNIA/NEVADA HAS KICKED IT OUT. KBRO RADAR CONTINUES TO SHOW
ECHOES DEVELOPING TO OUR SOUTHWEST AND MOVE INTO THE MIDDLE/UPPER
VALLEY. WITH WEAK DIFFLUENCE PERSISTING AND PWATS OF AROUND 2
INCHES AND A WEAK PERTURBATION EMBEDDED IN THE FLOW AS WELL...THE
BEST SHOT OF SEEING PRECIPITATION WILL BE THIS MORNING. AS THE LOW
CONTINUES TO SHIFT NORTHEAST TODAY AND DRIER AIR FILTERS IN
THROUGH THE MID LEVELS ON WESTERLY FLOW ALOFT...PWATS DROP
SIGNIFICANTLY THIS AFTERNOON AND EFFECTIVELY SHUTS DOWN THE
PRECIPITATION CHANCES FROM WEST TO EAST. AT THE SAME TIME...LEE
TROUGHING DEVELOPS TO OUR WEST WHICH WILL AID IN INCREASING
SOUTHEASTERLY WINDS STARTING TODAY WITH BREEZY CONDITIONS BY LATE
MORNING AND ONCE AGAIN ON THURSDAY.

CLOUDS WILL HANG IN THROUGH MUCH OF THE DAY IN DEEP SOUTH TEXAS
WHICH WILL KEEP TEMPERATURES FROM REACHING THERE FULL POTENTIAL.
HOWEVER...DOWNSLOPING WINDS WILL PUSH HIGHS INTO THE LOWER 90S IN
THE UPPER VALLEY WITH A LESSENING EFFECT FURTHER EAST WHERE HIGHS
WILL BE IN THE MIDDLE 80S. THE HEAT IS ON BEGINNING THURSDAY WITH
THOSE SAME DOWNSLOPING WINDS AND SUBSIDENCE BUILDING IN TO THE LOWER
AND MIDDLE LAYERS OF THE ATMOSPHERE. PLENTY OF SUNSHINE WILL PUSH
HIGHS OVER THE CENTURY MARK IN THE UPPER VALLEY DECREASING TO THE
UPPER 80S IN THE LOWER VALLEY.

LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
HEAT..HUMIDITY...AND WIND REMAIN THE PRIMARY ISSUES IN THE LONG
TERM...STRONG SUBSIDENCE BY THE ONSET OF THE PERIOD SHOULD PUT IN
PLACE BOTH A STRONG SUBSIDENCE CAPPING INVERSION AND HELP TO
INCREASE LOW AND MID LEVEL THICKNESSES QUITE A BIT. LOCAL
SUBTLETIES WILL PROBABLY PLAY THE BIGGEST ROLE IN JUST HOW HOT IT
GETS EACH DAY.

FRIDAY WEAK LEE TROUGHING INDUCED BY A WEST SOUTHWESTERLY JET OVER
THE SIERRA MADRE MOUNTAINS SHOULD HAVE OUR LOW LEVEL FLOW JUST
SLIGHTLY MORE EASTERLY AND ONSHORE...MODERATING ACTUAL AIR
TEMPERATURES RIGHT ALONG THE COAST BUT INCREASING OVERALL HUMIDITY.
NAM/GFS ARE STILL INSISTENT ON MIXING DRIER AIR DOWN IN THE
AFTERNOON LIMITING THE RH VALUES AND KEEPING HEAT INDICES AT MORE
REASONABLE LEVELS BUT PROJECTED MAX TEMPERATURES ARE 95 DEGREES AND
ABOVE WEST OF HIGHWAY 281 AND NEAR 90 HIGHWAY 77 WESTWARD.

SATURDAY THE LEE TROUGHING LOOKS TO GET A LITTLE STRONGER...WITH
TOTAL WIND SPEEDS PROBABLY A COUPLE MPH HIGHER...19 TO 24 MPH
GUSTING TO 35 MPH TYPE WINDS. THE TRAJECTORY OF THE WINDS WILL
PROBABLY BE SLIGHTLY MORE OUT OF THE SOUTH LEADING TO WARMER
CONDITIONS ALONG THE COAST AND IN OUR WESTERN COUNTIES. AS THE
TROUGHING GETS CLOSER ON SUNDAY WINDS SHOULD BE MORE SOUTHEASTERLY
ALBEIT FAIRLY BRISK. THE HIGHEST AIR TEMPERATURE WILL PROBABLY BE ON
SATURDAY BUT HEAT INDICES WILL PROBABLY BE IN THE 100 TO 105 DEGREE
RANGE...IF NOT A LITTLE HIGHER EACH DAY.

MONDAY THROUGH TUESDAY LOOK TO HAVE SIMILAR WARMTH WITH SUBSIDENCE
ALOFT...AND FAIRLY HIGH THICKNESS VALUES. SURFACE WINDS WILL BE
BREEZY BUT LIKELY LOWER OVERALL WITH THE MORE SYNOPTIC SCALE
DISTURBANCE PARTING TO THE EAST AND NORTHEAST. LOW LEVEL HUMIDITY
WILL BE BROKEN UP BY MIXING AWAY FROM THE COAST IN THE LATE
AFTERNOON BUT A GENERALLY ZERO SUM GAME IN TERMS OF HEAT RELIEF IS
EXPECTED.

MARINE...
TODAY THROUGH THURSDAY...MODERATE TO STRONG SOUTHEAST WINDS WILL
PREVAIL ACROSS THE LOWER TEXAS COASTAL WATERS THIS PERIOD. SHOWERS
AND THUNDERSTORMS WILL BE POSSIBLE THIS MORNING INTO THE EARLY
AFTERNOON HOURS AS A MID LEVEL LOW EXITS THE REGION. CLOUDY SKIES
WILL DECREASE THURSDAY WITH PLENTY OF SUNSHINE IN STORE. WAVE
HEIGHTS WILL SLOWLY BUILD AS THE WIND SPEEDS INCREASE...REACHING 4-6
FEET THIS AFTERNOON.

THURSDAY NIGHT THROUGH MONDAY... AFTERNOON WINDS ON THE LAGUNA WILL
LIKELY BE AT EXERCISE CAUTION LEVELS WITH OVERNIGHT WINDS ON THE
OPEN GULF WATERS NEAR THE SAME LEVEL. LITTLE CHANGE IN THIS
PATTERN IS EXPECTED THROUGH MONDAY. AT THIS TIME THE STRONGEST
WINDS IN THE LONG RANGE LOOK TO BE ON SATURDAY NIGHT INTO SUNDAY
MORNING. SMALL CRAFT ADVISORY WINDS AND SEAS ARE POSSIBLE DURING
THIS TIME.
&&

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

$$

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