Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 061729
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1229 PM CDT SUN JUL 6 2014

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

&&

.AVIATION...MOSTLY CLEAR SKIES EMERGING ACROSS THE REGION. SOME
CUMULUS CLOUD FORMATION IS LIKELY THROUGH MID TO LATE AFTERNOON
BUT ALL CLOUDS SHOULD BE ABOVE 3000 FT WITH THE ODDS FOR
OPERATIONALLY SIGNIFICANT PRECIP VERY LOW. SOUTHEAST WINDS GUSTING
TO AROUND 20 KTS EXPECTED FOR THE REST OF THE DAY DECREASING AFTER
SUNSET. VFR CONDITIONS FORECAST THROUGH TONIGHT AND THE MORNING ON
MONDAY. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 616 AM CDT SUN JUL 6 2014/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...MID TO HIGH LEVEL CLOUDINESS SPREADING SOUTH TO NORTH
OVER THE LOWER AND MIDDLE VALLEY TO THIN THROUGH THE MORNING. VFR
CONDITIONS TO PREVAIL WITH SCT CUMULUS TO DEVELOP WITH THE HEATING
OF THE DAY. SOUTHEAST WINDS WILL BE A BIT MORE PREVALENT THIS
AFTERNOON WITH GUSTS AROUND 20 KNOTS AT TIMES.

PREV DISCUSSION... /ISSUED 408 AM CDT SUN JUL 6 2014/

SHORT TERM /TODAY THROUGH MONDAY/...A SPLIT IN THE 250MB TROUGH HAS
LEFT DEEP SOUTH TEXAS UNDER WEAK UPPER FLOW. SHEAR AXIS REMAINS
PRESENT BUT DIVERGENT FLOW IS CONSIDERABLE LESS THAN YESTERDAY. AT
THE SURFACE HIGH PRESSURE OVER THE WESTERN GULF MOVING SLOWLY EAST
WILL PROVIDE A MORE SOUTHERLY FLOW THAN THE EASTERLY FETCH OF THE
LAST FEW DAYS. ATMOSPHERIC MOISTURE ALSO A SCOSH LOWER TODAY WITH
PWATS EXPECTED TO DROP OFF NEAR 1.7 INCHES INSTEAD OF THE SULTRY 2.1
NOTED ON SATURDAY`S MORNING RUN. MEAN RH VALUES HAVE ALSO ABATED
SLIGHTLY AND WILL REMAIN IN THE 60-70 PERCENT RAIN. EXPECT THESE
CONDITIONS TODAY AND MONDAY WITH SLIGHT CHANCE OF A DIURNAL SHOWERS
OR THUNDERSTORMS. MAJORITY OF CONVECTION...IF IT DOES DEVELOP...TO
FAVOR LOCALS JUST NORTH OF THE LOWER AND MID VALLEY DUE TO THE MORE
SOUTHERLY FLOW. A LITTLE MORE WIND WITH A THE NEXT FEW AFTERNOONS AS
THE SOUTHERLY GRADIENT STRENGTHENS BETWEEN THE SURFACE RIDGE IN THE
GULF INTERACTING WITH THE THERMAL LOW OVER LEE SIDE OF SIERRA
MADRES.

TEMPERATURES SHOW LITTLE CHANGE WITH THE NEAR NORMAL READINGS EACH
DAY. LOW PRESSURE ALOFT TO LIMIT COMPRESSION THAT HIGH PRESSURE
USUALLY BRINGS AND 850 TEMPS REMAIN NEAR 18C WHICH IS IN THE 50
PERCENTILE RANGE. MODEL GUIDANCE WITHIN A DEGREE OR TWO OF EACH.
TRENDED WITH BLEND WITH SOME MINOR ADJUSTMENTS UPWARD DUE TO THE
LOWER AREAL COVERAGE OF CONVECTION.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY NIGHT/...THE RIO GRANDE
VALLEY AND DEEP SOUTH TEXAS WILL REMAIN BETWEEN 500 MB RIDGES OVER
THE FOUR CORNERS AND NEAR BERMUDA THROUGH MOST OF THE FORECAST
PERIOD. MID LEVEL WEAKNESS WILL PREVAIL ACROSS THE REGION THROUGH
LATE WEEK WITH BROAD SURFACE HIGH PRESSURE ACROSS THE EASTERN GULF
OF MEXICO. THE MID LEVEL WEAKNESS OVERHEAD COMBINED WITH LIGHT TO
MODERATE WINDS AND PRECIPITABLE WATER VALUES OF 1.6 TO 1.9 INCHES
WILL RESULT IN STREAMER SHOWERS AND SEA BREEZE CONVECTION EACH DAY.
THE BEST CHANCES OF SHOWERS AND THUNDERSTORMS WILL BE WEDNESDAY AND
THURSDAY AS THE MID LEVEL TROUGH AXIS/UPPER LOW MOVES TO OUR WEST
AND BETTER DIFFLUENCE ALOFT. OVERNIGHT LOW TEMPERATURES WILL BE IN
THE MID TO UPPER 70S. HIGH TEMPERATURES EACH DAY WILL RANGE FROM THE
UPPER 80S NEAR THE COAST TO THE UPPER 90S ACROSS THE WEST.

MARINE...TODAY THROUGH MONDAY...SURFACE HIGH PRESSURE OVER THE WESTERN
GULF TO MOVE EASTWARD WITH THE PRESSURE GRADIENT STRENGTHENING EVER
SO SLIGHTLY. FRESH SOUTHERLY TO SOUTHEASTERLY BREEZE NOT TO EXCEED
EXERCISE CAUTION LEVELS AND FETCH TO REMAIN LOCALIZED FOR SEAS TO
REMAIN AT 3 FEET OR LESS. ISOLATED SHOWERS OR THUNDERSTORMS ARE
POSSIBLE EACH NIGHT AND INTO THE EARLY MORNING HOURS.

MONDAY NIGHT THROUGH THURSDAY...LIGHT TO MODERATE SOUTHEAST WINDS
AND LOW TO MODERATE SEAS WILL PREVAIL ACROSS THE LOWER TEXAS COASTAL
WATERS AS HIGH PRESSURE CONTINUES OVER THE GULF. SHOWERS AND
THUNDERSTORMS POSSIBLE ACROSS THE COASTAL WATERS THROUGH LATE WEEK.

&&

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

$$

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