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 041131
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
631 AM CDT MON MAY 4 2015

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

&&

.AVIATION...FOR THE 12Z TAFS...TEMPO MVFR STRATUS CURRENTLY AT MFE
WITH VFR CIGS AT BRO AND HRL. HAVE A TEMPO FOR CIGS AT MFE THROUGH
13Z. WINDS WILL PICK UP AROUND 14Z WITH SOUTHEAST WINDS SUSTAINED
NEAR 17 KNOTS WITH GUSTS TO 25 KNOTS. CIGS WILL BE VFR TODAY WITH
DIURNAL CUMULUS DEVELOPING AROUND 2500 FEET THIS MORNING RISING TO
4000 FEET THIS AFTERNOON. WINDS DECREASE AFTER SUNSET WITH MVFR
CIGS MOVING IN TOWARDS MIDNIGHT ACROSS ALL THE TAF SITES LASTING
THROUGH THE END OF THE PERIOD.

&&

.PREV DISCUSSION... /ISSUED 407 AM CDT MON MAY 4 2015/

SHORT TERM.../NOW THROUGH TUESDAY/...LATEST WATER VAPOR IMAGERY
DEPICTS TROUGHING ACROSS THE SOUTHWESTERN CONUS WITH DIFFLUENT FLOW
ACROSS THE SIERRA MADRES LEADING TO ISOLATED SHOWERS ACROSS WESTERN
TEXAS AND THE BIG BEND AREA. SURFACE TROUGHING IS DEEPENING AHEAD OF
THE UPPER TROUGH THROUGH THE LEE OF THE ROCKY MOUNTAINS AND HIGH
PRESSURE RIDGING IS DRAPED ACROSS OUR AREA. THE TROUGH WILL MOVE
ASHORE THIS MORNING THEN MOVE NORTHEASTWARD INTO COLORADO BY
TUESDAY. THE BETTER DYNAMICS WILL LIE NORTH AND WEST OF THE REGION
BUT AN ISOLATED THUNDERSTORM OR TWO WILL BE POSSIBLE. THE BEST
CHANCES /ALBEIT SLIGHT/ WILL RESIDE OUT WEST TODAY WHERE BETTER
MOISTURE WILL BE LOCATED ALONG WITH A WEAKENING OF THE CAP DUE TO
WEAKENING SOUTHWEST FLOW. SOUTHWEST FLOW STRENGTHENS TUESDAY WHICH
WILL STRENGTHEN THE CAP ONCE AGAIN WITH RAIN HARD PRESSED TO
DEVELOP. THE STRONGER LOW LEVEL WINDS TODAY AND TUESDAY WILL LEAD TO
BREEZY CONDITIONS IN THE LATE MORNING AND AFTERNOON WITH GUSTS UP TO
30 MPH POSSIBLE. HIGHS WILL BE COMPARABLE TO THE PAST SEVERAL
DAYS...MID 80S STARTING IN THE LOWER VALLEY TO UPPER 80S TO AROUND
90 DEGREES IN THE UPPER VALLEY AND RANCHLANDS.

LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...LITTLE CHANGE IN THE
WEATHER PATTERN AS DEEP SOUTH TEXAS IS CONCERNED. A STEADY STATE
SPLIT FLOW TO KEEP THE REGION UNDER A GENERAL ZONAL SW-W MID TO
TO UPPER LEVEL FLOW AND A CONTINUOUS SOUTHEAST SURFACE FLOW.
RELEVANT FEATURES THAT WILL BE MONITORED ARE A SHORTWAVE TROUGH
PASSING THROUGH THE SOUTHERN AND CENTRAL PLAINS TUESDAY NIGHT AND
WEDNESDAY. A DEVELOPING LOW PRESSURE AREA OFF THE EAST COAST OF
FLORIDA...WITH SOME POSSIBLE HYBRID/SUBTROPICAL CHARACTERISTICS
AND A LARGER UPPER TROUGH TAKING UP REALESTATE OVER THE SOUTHWEST
DESERTS AND ROCKIES FRIDAY AND THROUGH NEXT WEEKEND.

THE DOMINATE SOUTHWEST FLOW TO WARM THE 850-700MB LAYER KEEPING
RAIN CHANCES LIMITED. MODELS REMAIN CONSISTENT WITH LOW POPS OVER
THE NORTHWEST AND EVEN LOWER PERCENTAGES AS YOU NEAR THE COAST.
TRYING TO FIND A MORE FAVORED DAY FOR PRECIPITATION BUT WITH NO
DISTINCT BOUNDARY OR DISTURBANCE SEEN TO PASS NEAR OUR CWA POP
PLACEMENT AND COVERAGE TO SOMEWHAT A CHALLENGE. LOOKING FOR BEST
FORCING AND LIFT TO OCCUR OVER THE SIERRA MADRE EACH AFTERNOON
THEN HAVE A FEW STORMS DRIFT INTO THE CWA. THERE HAS BEEN AN
ISOLATED SHOWER DEVELOPING OVER THE COASTAL WATERS THE LAST FEW
NIGHTS AND WITH WATERS TEMPERATURES IN THE MID 70S THERE MAY BE
SOME ENHANCEMENT OF OVERNIGHT STREAMER SHOWERS THROUGH MID AND
LATE IN THE AS THE LOW LEVEL SOUTHEAST FLOW IS MAINTAINED.

WILL BE WATCHING THE DEVELOPMENT OF A LOW PRESSURE AREA ALONG AN
OLD FRONTAL BOUNDARY OVER SOUTHERN FLORIDA. GFS AND ECMWF CONTINUE
TO INDICATE SOME HYBRID/SUBTROPICAL DEVELOPMENT OF THIS LOW AS IT
MEANDERS OFF THE FLORIDA/GEORGIA COAST. ALTHOUGH NO DIRECT IMPACT
ON DEEP SOUTH TEXAS A MID LEVEL RIDGE MAY STRENGTHEN OVER THE
WESTERN GULF THURSDAY THROUGH SATURDAY. THIS IS LIKELY THE FEATURE
THAT WILL KEEP RAIN CHANCES RATHER LOW OVER THE EASTERN HALF OF
THE CWA AND LIMIT ANY DAYTIME SHOWERS OVER THE ADJACENT COASTAL
WATERS.

TEMPERATURES WILL BE NEAR SEASONAL NORMALS EARLY ON THEN INCH
UPWARD AS THE MENTION RIDGE BUILDS LATER IN THE WEEK. MODEL
GUIDANCE IS TRENDING IN THIS DIRECTION WITH DAY TO DAY GUIDANCE
SHOWING LITTLE CHANGE TEMPERATURES REMAIN UNCHANGED FROM PREVIOUS
FORECASTS.

MARINE...NOW THROUGH TUESDAY...INTERACTION BETWEEN THE HIGH
PRESSURE OVER THE NORTHERN GULF COAST AND LOW PRESSURE OVER WEST
TEXAS WILL STRENGTHEN THE PRESSURE GRADIENT ACROSS THE GULF WATERS
TODAY THROUGH TUESDAY. WIND SPEEDS MAY INCREASE TO EXERCISE CAUTION
LEVELS OVERNIGHT TONIGHT AND THEN SEA HEIGHTS MAY REACH 6 FEET
TUESDAY AFTERNOON DUE TO A LONG AND PERSISTENT SOUTHEAST FETCH
BUILDING UP THE SEAS REQUIRING EXERCISE CAUTION IN THE 20-60NM
WATERS.

TUESDAY NIGHT THROUGH FRIDAY...BROAD HIGH PRESSURE OVER THE GULF
TO CONTINUES TO COMBINE WITH LOWER PRESSURE ACROSS THE SOUTHERN
AND CENTRAL PLAINS. THIS WILL RESULT IN A CONTINUATION OF MARGINAL
SCA WINDS AND BUILDING SEAS. FORECAST REMAINS UNCHANGED FROM
YESTERDAY AND PERSISTENCE LOOKS TO BE THE BEST FORECAST AT THIS
TIME. EXERCISE CAUTION CONDITIONS ARE LIKELY TO BE THE DOMINATE
WIND IMPACT WITH SEAS HAVING THE POTENTIAL TO APPROACH SMALL CRAFT
ADVISORY LEVELS AS THE ENERGY OF AN ANTICIPATED LONG FETCH OF
MODERATE TO GUSTY WINDS IS TRANSFERRED TO THE WATER BUILDING THE
WAVES PEAKING TUESDAY NIGHT THROUGH WEDNESDAY NIGHT.

&&

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

$$

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

55



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