Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 200555 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1255 AM CDT SUN APR 20 2014

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

&&

.AVIATION...BKN TO OVC HIGH CLOUD DECK PREVAILS ACROSS DEEP SOUTH TEXAS
EARLY THIS MORNING. VFR CEILINGS TO LOWER STEADILY OVERNIGHT WITH
WIDESPREAD MVFR AROUND 8Z. THE LOW CLOUDS TO INHIBIT ANY DENSE FOG
FROM FORMING OVERNIGHT. CEILINGS TO REMAIN AT MVFR THROUGH THIS
MORNING BEFORE IMPROVING TO VFR BUT SHOULD REMAIN BKN TO OVC
AROUND 3500 FEET THIS AFTERNOON. SOUTHEAST WINDS DROP TO 10 KNOTS
OR LESS OVERNIGHT THEN BECOME BREEZY WITH GUST UP TO 25 KNOTS BY
LATE MORNING THROUGH THE AFTERNOON HOURS. WINDS BEGIN TO DECOUPLE
SLIGHTLY AFTER SUNSET WITH LOW CLOUDS RETURNING BY LATE EVENING.

&&

.PREV DISCUSSION... /ISSUED 623 PM CDT SAT APR 19 2014/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...VFR CEILINGS TO LOWER STEADILY OVERNIGHT WITH
WIDESPREAD MVFR. THE LOW CLOUDS TO INHIBIT ANY DENSE FOG FROM
FORMING AND A STRONG ENOUGH BREEZE SHOULD KEEP VSBY 5 MILES OR
BETTER OVERNIGHT. CIGS TO REMAIN AT MVFR THROUGH SUNDAY MORNING
BEFORE IMPROVING TO VFR BUT REMAINING BKN TO OVC SUNDAY AFTERNOON.
SOUTHEAST WINDS DROP TO 10 KNOTS OR LESS TONIGHT THEN BECOME
BREEZY WITH GUST UP TO 25 KNOTS.

PREV DISCUSSION... /ISSUED 215 PM CDT SAT APR 19 2014/

SHORT TERM /NOW THROUGH SUNDAY NIGHT/...THICKER DECK OF STRATOCU
HAS DEVELOPED OVER MUCH OF THE AREA AS MOIST SOUTHEASTERLY WINDS
CONTINUE TO ADVECT HIGHER MOISTURE IN THE AREA. ALOFT...MID LEVEL
RIDGING OVER THE AREA THE PAST 24 HOURS IS BEING SHUNTED EASTWARD AS
A MID LEVEL TROUGH MOVES INTO SOUTHERN ARIZONA. MID LEVEL FLOW IS
BECOMING INCREASINGLY SOUTHWESTERLY WITH A SUBTROPICAL TAP OF MID
AND HIGH LEVEL MOISTURE OVERSPREADING THE REGION. NO PRECIPITATION
ON THE SCOPE THIS AFTERNOON AND TEMPERATURES HAVE WARMED INTO THE
MIDDLE TO UPPER 70S.

CONTINUED TREND OF SLIGHT CHANCE OF THUNDERSTORMS IN THE FAR WEST
TONIGHT AS PWATS INCREASE TO 1.6 INCHES WITH EMBEDDED WEAK
DISTURBANCES RIDING THROUGH THE FLOW WITH INCREASING BROAD
DIFFLUENCE ALOFT. ANY CONVECTION WOULD FIRE OVER THE HIGHER TERRAIN
AND POSSIBLY SNEAK INTO THE FAR WESTERN SECTION. CAP AGAIN IS FAIRLY
STRONG SO PROBABLY WOULD NOT AMOUNT TO A WHOLE LOT.
OTHERWISE...PARTLY TO MOSTLY CLOUDY SKIES EXPECTED OVERNIGHT WITH
LOWS FALLING INTO THE 60S.

MID LEVEL TROUGH LIFTS NORTHEASTWARD SUNDAY TAKING THE BETTER
CHANCES FOR PRECIPITATION WITH IT. HOWEVER...ENOUGH MOISTURE AND
DYNAMICS AROUND TO WARRANT A SLIGHT CHANCE POP OVER MOSTLY LAND
AREAS SUNDAY. A STREAMER SHOWER OR TWO OVER THE COASTAL WATERS
CANNOT BE RULED OUT AS WELL. IT WILL REMAIN MOSTLY CLOUDY WITH HIGHS
IN THE 80S.

CONVECTION LOOKS TO FIRE ON THE HIGHER TERRAIN AGAIN LATE SUNDAY
INTO SUNDAY NIGHT. SAME RULES APPLY AS TONIGHT...MAYBE ONE OR TWO
SNEAKS INTO THE WESTERN AREAS. MOSTLY CLOUDY SKIES CONTINUE WITH
LOWS IN THE 60S.

LONG TERM.../MONDAY THROUGH SATURDAY/...THE 500 MB TROUGH THAT IS
MOVING OUT OF THE DESERT SOUTHWEST ACROSS THE SOUTH CENTRAL PLAINS
STATES WILL EVENTUALLY CLEAR THE REGION ON MON. 500 MB RIDGING
WILL THEN BUILD OVER TX WHICH WILL ALLOW THE TEMPS TO WARM UP
STEADILY THROUGHOUT THE LONGER RANGE PERIOD. A DEEPER 500 MB
TROUGH AXIS WILL THEN DIG ACROSS THE CENTRAL PORTION OF THE LOWER
48 STATES TOWARDS THE END OF NEXT WEEK WHICH WILL BUILD A PRETTY
STRONG SURFACE LOW OVER THE CENTRAL STATES. THIS WILL TIGHTEN UP
THE SURFACE PGF RESULTING IN BREEZIER CONDITIONS ON THURS AND FRI.

DEEPER LAYER MOISTURE WILL REMAIN PRETTY LIMITED OVER THE AREA
WITH THE BEST MOISTURE VALUES ASSOCIATED WITH THE FIRST 500 MB
TROUGH MOVING OUT OF THE DESERT SOUTHWEST EARLY NEXT WEEK. WILL
MAINTAIN ONLY SLGT CHC POPS AT THIS TIME AS THE BULK OF THE 500 MB
VORTICITY MOVES WELL NORTH OF DEEP SOUTH TX MISSING THE LOWER RGV.

RUN TO RUN CONSISTENCY WITH THE GFS MEX MOS GUIDANCE IS PRETTY
STABLE THROUGH DAY 7. MODEL TO MODEL CONSISTENCY BETWEEN THE GFS
AND ECMWF IS IN PRETTY GOOD AGREEMENT THROUGHOUT THE LONGER RANGE
PERIOD WITH THE EXCEPTION OF THE HANDLING OF THE 2ND 500 MB TROUGH
AXIS MOVING ACROSS THE CENTRAL STATES DURING THE LATTER HALF OF
NEXT WEEK. THE ECMWF HAS A LITTLE MORE NORTHWARD PLACEMENT OF THE
500 MB LOW VERSUS THE GFS BUT WITH ROUGHLY THE SAME TIMING. OVERALL
CONFIDENCE IN THE LONGER RANGE FORECAST WORDING REMAINS ABOVE
AVERAGE DUE TO THE GOOD MODEL CONSISTENCY.

FOR HIGH TEMPS WILL LEAN MORE TOWARDS THE SLIGHTLY WARMER ECMWF
GUIDANCE. FOR LOW TEMPS WILL GO WITH A MODEL BLEND BETWEEN THE MEX
MOS AND ECMWF.

MARINE...NOW THROUGH SUNDAY NIGHT...BUOY 42020 REPORTED EAST-
SOUTHEAST WINDS AROUND 8 KNOTS GUSTING TO AROUND 10 KNOTS WITH
SEAS SLIGHTLY OVER 4 FEET WITH A PERIOD OF 9 SECONDS AT 13 CDT/18
UTC. SURFACE HIGH PRESSURE WILL REMAIN CENTERED ALONG THE COAST OF
LOUISIANA AND EXTENDED OVER THE LOWER TEXAS COAST THROUGH THE
PERIOD...PRODUCING GENERALLY MODERATE WINDS AND SEAS FOR THE
WEEKEND. HOWEVER...SMALL CRAFT MAY NEED TO EXERCISE CAUTION ON THE
LAGUNA MADRE ON SUNDAY DUE TO BREEZY WINDS.

MONDAY THROUGH THURSDAY...A MODERATE PGF WILL PREVAIL THROUGHOUT
THE LONGER RANGE MARINE PERIOD AS SURFACE RIDGING REMAINS IN PLACE
OVER THE GULF OF MEX. THIS WILL LIKELY KEEP THE BAY AND GULF
WINDS AND SEAS DOWN BELOW SCA LEVELS THROUGH TUESDAY. HOWEVER AFTER
MIDWEEK...A SURFACE LOW DEVELOPING OVER THE CENTRAL PLAINS STATES WILL
LIKELY STRENGTHEN THE PGF ALONG THE LOWER TX COASTLINE POSSIBLY
PUSHING CONDITIONS UP CLOSE TO SCEC/SCA LEVELS ON WED AND THURS.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  68  81  67  84 /  10  20  10  10
BROWNSVILLE          68  83  66  86 /  10  20  10  20
HARLINGEN            67  83  66  87 /  10  20  20  20
MCALLEN              68  85  69  91 /  20  20  20  20
RIO GRANDE CITY      67  88  68  92 /  20  20  20  20
SOUTH PADRE ISLAND   68  75  67  82 /  10  20  10  10

&&

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

$$

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

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