Area Forecast Discussion
Issued by NWS Brownsville, TX

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS64 KBRO 302344
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
644 PM CDT TUE SEP 30 2014

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

&&

.AVIATION...WEAK LOW PRESSURE AREA OVER DEEP SOUTH TEXAS DISSIPATING
AS IT DRIFTS NORTHWARD. CUMULUS FIELD AND ANY LEFT OVER SHOWERS
SHOULD QUICKLY DISSIPATE WITH VFR CONDITIONS PREVAILING MOST OF
THE EVENING. RESIDUAL SHALLOW SURFACE MOISTURE AND WET GROUND FROM
RECENT RAIN AND LIGHT WINDS OVERNIGHT COULD ALLOW FOR ANOTHER
ROUND OF DENSE PATCHY GROUND FOG AROUND SUNRISE. MODELS SUGGEST LOW
PROBABILITY OF THIS OCCURRING WITH GOING TAF FORECAST INDICATING
JUST A FEW HOURS OF LIGHT FOG A FEW HOURS EITHER SIDE OF SUNRISE.
BRIEF MVFR TO IFR CONDITIONS DURING THE FOG OR STRATUS THEN VFR
RETURNS FOR WEDNESDAY AS DAYTIME HEATING MIXES OUT THE LOW LEVEL
MOISTURE. LIGHT WINDS OVERNIGHT BECOME MORE SOUTHERLY WEDNESDAY
WITH SOME GUSTS APPROACHING 20 KNOTS IN THE AFTERNOON.



&&

.PREV DISCUSSION... /ISSUED 306 PM CDT TUE SEP 30 2014/

SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...DAYTIME HEATING HAS
COMBINED WITH THE AFTERNOON SEA BREEZE TO ALLOW FOR SOME CONV
FORMATION MAINLY OVER KENEDY AND BROOKS COUNTIES. THIS ACTIVITY IS
BEING HELPED ALONG BY WHAT APPEARS TO BE A MESOLOW SPINNING OVER THE
AREA ON VSBL SATL. THIS MESOLOW APPEARS TO BE MOVING SLOWLY
NORTHWARDS WHICH WILL LIKELY KEEP THE CONV LIMITED TO NEAR THE
COASTAL AREAS WHERE THE LATEST LAPS CAPE VALUES SHOW THE MOST
UNSTABLE AIR LINGERING. THIS MORNINGS BRO SOUNDING SHOWED MORE
LIMITED PWAT VALUES OVER THE REGION WHICH WILL ALSO KEEP THE CONV
MORE LIMITED VERSUS THE ACTIVITY YESTERDAY.

BOTH THE NAM AND GFS MAINTAIN FAIRLY DRY TRENDS IN PLACE OVER THE
REGION AS THE WINDS ALOFT REMAIN MORE WEST TO SOUTHWESTERLY THROUGH
THE SHORT TERM PERIOD AS INDICATED BY THE FORECAST SOUNDINGS. SO FOR
NOW WILL KEEP ONLY SLGT CHC POPS IN PLACE OVER THE AREA THROUGH WED
NIGHT WITH THE BEST CONV CHCS REMAINING LIMITED TO THE GULF WATERS
WHERE SOME LINGERING INSTABILITY MAY FIRE UP A LITTLE MORE CONV
POTENTIAL.

AS THE ATMS DRIES OUT EXPECT A LITTLE WARMER HIGH AND LOW TEMPS
THROUGH TOMORROW NIGHT AS DAYTIME HEATING KICKS IN. THE MET/MAV AND
ECMWF MAX AND MIN TEMPS ALL REMAIN IN PRETTY CLOSE AGREEMENT THROUGH
WED NIGHT. SO WILL GO WITH A GENERAL BLEND OF THESE THREE MODELS.

LONG TERM /THURSDAY THROUGH TUESDAY/...THE 500MB TROUGH OVER THE HIGH
PLAINS THURSDAY MORNING WILL MOVE EASTWARD ACROSS THE CENTRAL U.S.
THURSDAY NIGHT INTO FRIDAY. THIS WILL BRING A WEAK COLD FRONT INTO
CENTRAL TEXAS THURSDAY AFTERNOON. RAIN CHANCES BEGIN TO INCREASE
ACROSS THE REGION ON THURSDAY AS MOISTURE POOLS AHEAD OF THE
FRONT. PRECIPITABLE WATERS REACH BETWEEN 1.5 TO 1.9 INCHES BY
THURSDAY AFTERNOON. HIGH TEMPERATURES THURSDAY WILL RANGE FROM THE
MID TO UPPER 80S ALONG THE BEACHES TO THE MID TO UPPER 90S ACROSS
THE WESTERN COUNTIES. LOW TEMPERATURES THURSDAY NIGHT WILL BE IN
THE MID TO UPPER 70S TO AROUND 80 NEAR THE COAST.

THE COLD FRONT WILL MOVE INTO THE NORTHERN RANCHLANDS FRIDAY MORNING
AND THROUGH THE RIO GRANDE VALLEY BY FRIDAY AFTERNOON.
HOWEVER...THERE ARE SOME TIMING ISSUES WITH THE FRONTAL PASSAGE
BETWEEN THE LATEST GFS/ECMWF MODEL GUIDANCE. MOISTURE POOLS AHEAD OF
THE COLD FRONT ON FRIDAY WITH PRECIPITABLE WATER VALUES AROUND 2
INCHES. THIS WILL SUPPORT A CHANCE OF SHOWERS AND THUNDERSTORMS
ACROSS DEEP SOUTH TEXAS ON FRIDAY. HIGH TEMPERATURES WILL REMAIN IN
THE 80S UNDER CLOUDY SKIES ON FRIDAY. RAIN CHANCES WILL CONTINUE
ACROSS THE AREA...ESPECIALLY ACROSS THE RIO GRANDE VALLEY AND ALONG
THE COAST...FRIDAY NIGHT INTO SATURDAY AS THE FRONT STALLS ACROSS
NORTHEAST MEXICO AND MOISTURE LINGERS ACROSS NORTHERN TAMAULIPAS.
DRIER AND SLIGHTLY COOLER AIR IS EXPECTED TO FILTER INTO THE REGION
THROUGH THE WEEKEND AS SURFACE HIGH PRESSURE SETTLES ACROSS EAST
TEXAS BEFORE MOVING EASTWARD BY EARLY NEXT WEEK. MOISTURE BEGINS TO
MOVE BACK ACROSS THE REGION ON MONDAY AS SOUTHEAST FLOW RETURNS.
LOW TEMPERATURES FRIDAY NIGHT AND SATURDAY WILL BE IN THE UPPER 60S
ACROSS THE NORTHERN RANCHLANDS TO THE LOWER 70S ACROSS THE RIO
GRANDE VALLEY. HIGH TEMPERATURES SATURDAY AND SUNDAY WILL BE IN THE
80S BEFORE TEMPERATURES GRADUALLY WARMING TO NEAR 90 BY EARLY NEXT
WEEK.

MARINE...NOW THROUGH WEDNESDAY NIGHT...A WEAK PGF WILL PERSIST
TONIGHT ON INTO EARLY WED WHICH WILL MAINTAIN FAIRLY LOW SEAS AND
WINDS. THE PGF WILL THEN START TO STRENGTHEN WED AFTERNOON AND WED
NIGHT AS A SURFACE LOW STARTS TO STRENGTHEN OVER THE CENTRAL PLAINS
STATES. THIS COULD PUSH THE GULF CONDITIONS UP TOWARDS SCEC CRITERIA
WED NIGHT MAINLY FOR WINDS. OTHERWISE NO SCA CONDITIONS EXPECTED
THROUGHOUT THE SHORT TERM PERIOD.

THURSDAY THROUGH SUNDAY...LIGHT TO MODERATE SOUTHEAST WINDS AND LOW
SEAS WILL PREVAIL ACROSS THE LOWER TEXAS COASTAL WATERS ON
THURSDAY. A WEAK COLD FRONT WILL MOVE THROUGH COASTAL WATERS ON
FRIDAY RESULTING IN WINDS SHIFTING TO THE NORTH AND NORTHEAST BY
FRIDAY AFTERNOON. THE PRESSURE GRADIENT MAY STRENGTHEN SLIGHTLY
ACROSS THE WESTERN GULF OF MEXICO ALLOWING FOR A BRIEF PERIOD OF
EXERCISE CONDITIONS FRIDAY AFTERNOON INTO FRIDAY NIGHT. LIGHT TO
MODERATE NORTHEAST TO EAST WINDS WILL PREVAIL ACROSS THE LOWER
TEXAS COASTAL SATURDAY AND SATURDAY NIGHT.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  77  90  80  89 /  10  10  10  20
BROWNSVILLE          76  90  79  90 /  10  10  10  20
HARLINGEN            75  91  78  92 /  10  10  10  20
MCALLEN              75  92  78  94 /  10  10  10  10
RIO GRANDE CITY      75  93  78  95 /  10  10  10  10
SOUTH PADRE ISLAND   79  87  81  87 /  10  20  20  20

&&

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

$$

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

59/68




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.