Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 291746 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1246 PM CDT SAT AUG 29 2015

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

.AVIATION...SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE
SOME MID LEVEL CLOUDS ACROSS THE SOUTHERN PORTIONS OF THE CWA
EARLY THIS AFTERNOON. CEILINGS WERE NEAR 4700FT AT KBRO. EXPECT
VFR CONDITIONS TO PREVAIL THE REST OF THE AFTERNOON INTO THE
EVENING AS LOW TO MID LEVEL MOISTURE REMAINS LIMITED ACROSS THE
CWA. ISOLATED CONVECTION IS EXPECTED TO DEVELOP ACROSS PORTIONS OF
THE RIO GRANDE VALLEY SUN MORNING AS A 500MB LOW ACROSS WEST-
CENTRAL TEXAS ALLOWS LOW TO MID LEVEL MOISTURE TO INCREASE ACROSS
THE COASTAL SECTIONS OF THE CWA.
&&

.PREV DISCUSSION... /ISSUED 644 AM CDT SAT AUG 29 2015/
DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...MORNING SATELLITE LOOPS INDICATE SCATTERED CUMULUS
ALONG AND EAST OF PADRE ISLAND. SKIES ARE CLEAR INLAND WITH VFR
CONDITIONS PREVAILING ACROSS ALL OF DEEP SOUTH TEXAS THIS MORNING.
HIGH PRESSURE AND DRY AIR OVERHEAD TO PROVIDE EXCELLENT FLYING
CONDITIONS WITH VFR PREVAILING THROUGH TONIGHT. LIGHT AND VARIABLE
WINDS THIS MORNING TO TURN EAST TO SOUTHEAST REMAINING LIGHT THIS
AFTERNOON.

PREV DISCUSSION... /ISSUED 348 AM CDT SAT AUG 29 2015/

SHORT TERM  /TODAY THROUGH SUNDAY/...DRY LAYER BETWEEN 5000-18000 FEET
TO REMAIN IN TACK AS SOUTH TEXAS REMAINS BETWEEN STRONG RIDGE TO THE
WEST AND A WEAK TROUGH TO OUR EAST. EVEN WITH A SLOW INCREASE IN LOW
LEVEL MOISTURE AS 850MB WINDS TURN SOUTH ATMOSPHERE WILL NOT BE
PRIMED FOR SHOWERS OR THUNDERSTORMS THROUGH SUNDAY. AN INCREASE IN
LOW LEVEL CLOUDS OVERNIGHT AND POSSIBLY HIGH AND LOW LEVEL CLOUDS
SUNDAY MIGHT BE THE MAIN IMPACT. THE WET BIASED NAM CONTINUES TO
INDICATE LOW END POPS AS IT INDICATES STREAMERS SHOWERS DEVELOPING
LATE TONIGHT AND SEA BREEZE ACTIVITY SUNDAY POSSIBLY DUE TO THE
SLIGHTLY HIGHER LOW LEVEL MOISTURE AS THE 85H WINDS RETURN. GFS AND
THE EC...AT LEAST IN THE FIRST 36 HOURS...STAY DRY AND DO NOT
INDICATE ANY RAIN CHANCES HIGHER THEN 10 PERCENT.  IN A NUTSHELL,
DRY CONDITIONS TO CONTINUE WITH SLIGHTLY HIGHER HUMIDITY SUNDAY.
TEMPERATURES ABOUT A DEGREE WARMER TODAY AND ANOTHER DEGREE OR TWO
SUNDAY. OVERNIGHT LOWS SATURDAY NIGHT ALSO A BIT WARMER WITH THE
NICE 60S DISAPPEARING AS THE 850 FLOW RETURNS FROM THE SOUTH WHICH
BUMPS UP OUR DEW POINTS. THE DRY COOL NIGHTS WERE NICE WHILE THEY
LASTED.

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...LONGER RANGE
MODELS DEPICT TROUGHING ACROSS THE CWA AND UNDER THE INFLUENCE OF
AN UPPER LOW. MODELS ARE STILL IN SOME DISAGREEMENT ON THE
POSITION OF THE UPPER LOW WHICH WOULD HAVE IMPACT ON OUR SENSIBLE
WEATHER. GFS IS A LITTLE FURTHER NORTHEAST WHICH LIMITS
PRECIPITATION CHANCES WHEREAS THE ECMWF IS A LOT CLOSER AND HAS
HIGHER CHANCES FOR PRECIPITATION ACROSS MOST OF THE AREA. MOST OF
THE ENSEMBLE MEMBERS LEAN TOWARDS THE GFS SOLUTION SO WILL FAVOR
THE GFS FOR THIS FORECAST PACKAGE. SINCE THE ECMWF MOS POP
NUMBERS ARE EXTREMELY HIGH...THIS SKEWS THE SUPERBLEND POPS
HIGHER AS WELL. WILL TRIM DOWN POPS TOWARDS GFS DETERMINISTIC AND
MOS NUMBERS. COLUMN RH VALUES... LL RH... AND PWATS DO NOT
SUPPORT THE HIGH POPS EITHER. GIVEN THE TRENDS OVER THE PAST
SEVERAL WEEKS WITH RESPECT TO POP CHANCES AND MODEL PERFORMANCE...
BELIEVE THE GFS IS THE BETTER CALL. HAVING SAID THAT... HAVE
EDGED TEMPERATURES A FEW DEGREES ABOVE SUPERBLEND AND LOWERED SKY
COVERAGE IN ANTICIPATION OF LOWER POP CHANCES.

MARINE...NOW THROUGH SUNDAY...WEAK SURFACE FLOW TO CONTINUE WITH
BROAD SURFACE HIGH CENTERED OVER THE NORTH CENTRAL GULF. SOUTHEAST
WINDS HAVE RETURNED AND COULD EVEN TURN MORE SOUTHERLY TONIGHT INTO
SUNDAY BUT REMAIN LIGHT TO OCCASIONAL MODERATE. WAVES AND SWELL TO
REMAIN STEADY STATE WITH NO WINDS TO SPEAK OF TO AGITATE THE SEA.

SUNDAY NIGHT THROUGH THURSDAY...LIGHT TO MODERATE ONSHORE WINDS
WILL PREVAIL ACROSS THE LOWER TEXAS COASTAL WATERS AS HIGH PRESSURE
REMAINS ACROSS THE WESTERN GULF AND LOWER PRESSURE ACROSS THE
HIGH PLAINS AND WEST TEXAS. WAVE HEIGHTS WILL BE IN THE 1-3
FOOT RANGE THROUGH THE PERIOD. ISOLATED TO SCATTERED SHOWERS AND
STORMS WILL BE POSSIBLE THROUGHOUT THIS PERIOD. NO SCEC OR SCA
EXPECTED DURING THIS PERIOD.
&&

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

$$

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