Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 031130
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
630 AM CDT THU SEP 3 2015

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

&&

.AVIATION...VFR TAFS EXPECTED TODAY. A BIT OF MORNING FOG NOW IN
THE MID VALLEY...BUT IT APPEARS RATHER LOCALIZED TO THE EBG AREA
AND WILL BURN OFF THIS MORNING. ISOLATED TO SCATTERED CONVECTION
OVER THE GULF...BUT MOST IS WELL OFFSHORE. WILL LIKELY SEE THE
SEA BREEZE AGAIN TODAY...WITH ADDITIONAL UNORGANIZED CONVECTION
IN THE AREA DUE TO POP UP SHOWERS AND ASSOCIATED OUTFLOW BOUNDARY
INTERACTION. SHOULDN`T BE A MAJOR ISSUE UNLESS THE CONVECTION
MOVES OVER THE AIRPORTS. SKIES WILL BECOME MOSTLY CLEAR AGAIN
TONIGHT.

&&

.PREV DISCUSSION... /ISSUED 419 AM CDT THU SEP 3 2015/

SHORT TERM /TODAY THROUGH FRIDAY/...THE LATEST WV IMAGERY SHOWS A
CIRCULATION JUST TO THE EAST OF BRO THIS MORNING. THIS VERIFIES THE
MODEL FORECAST OF THIS FEATURE`S SOUTHWARD MOVEMENT FROM YESTERDAY.
DRIER AIR IS TO THE WEST OF THE CIRCULATION...PRETTY MUCH COVERING
THE CWA. RADAR SHOWS ISOLATED CONVECTION OVER THE GULF TO THE EAST
THROUGH SOUTH OF BRO HOWEVER.

THE MARINE CONVECTION SHOULD NOT POSE MUCH OF A PROBLEM FOR THE CWA.
ON THE OTHER HAND...FORECAST PWAT WILL REMAIN NEAR TWO INCHES TODAY
AND FRIDAY...WITH THE HRRR SHOWING THE DEVELOPMENT OF A SEA BREEZE
FROM LATE MORNING TO MID AFTERNOON. MOSTLY CLEAR SKIES THIS MORNING
WILL GIVE EARLY ON DAYTIME HEATING A CHANCE TO CONTRIBUTE TO THE
ACTION...WITH OUTFLOW BOUNDARIES FROM COLLAPSING CELLS INTERSECTING
WITH EACH OTHER AND WITH THE SEA BREEZE. EFFICIENT TROPICAL...SUMMER
TIME RAIN MAKING CELLS MAY RESULT IN BRIEFLY HEAVIER DOWNPOURS...
WITH NUISANCE FLOODING POSSIBLE IN SOME AREAS.

THE UPPER CIRCULATION MAY BE ABLE TO REMAIN IDENTIFIABLE FOR ANOTHER
24 HRS AS IT DRIFTS FARTHER SOUTH AND WEST...BUT IT WILL EVENTUALLY
BE OVERSHADOWED BY RIDGING BUILDING OVER TEXAS. HOWEVER...THIS WILL
NOT TOTALLY SUPPRESS ANOTHER DAY OF UNORGANIZED CONVECTION AROUND
THE AREA FRIDAY...SOME OF WHICH WILL FEED OFF THE SEA BREEZE.

HAD NO REAL ISSUES CONTINUING WITH A MODEL CONSENSUS TO BUILD THE
SHORT TERM FORECAST. HIGH TEMPERATURES OUT WEST ARE DRIFTING UP A
BIT...TOPPING OUT NEAR THE CENTURY MARK FRIDAY AFTERNOON. POPS ARE
STILL PAINTED SLIGHTLY HIGHER OVER THE GULF THAN OVER LAND AREAS.

LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...500 MB RIDGING WILL
REBUILD OVER TX AND NORTHERN MEXICO THIS WEEKEND INTO NEXT WEEK.
THIS WILL ALLOW A DRIER AND MORE SUBSIDENT ATMS TO BUILD OVER THE
AREA. THE BETTER MOISTURE VALUES WILL REMAIN CONFINED MAINLY TO
THE OFFSHORE WATERS AND NEAR THE COASTLINE AS A 500 MB CLOSED LOW
DEVELOPS OVER THE EASTERN AND CENTRAL GULF OF MEX. OVERALL THIS
TREND WILL TEND TO LIMIT THE CONV POTENTIAL THROUGHOUT THE
EXTENDED RANGE PERIOD. HOWEVER ISOLD MAINLY SEA BREEZE/DIURNALLY
DRIVEN CONV WILL REMAIN A THREAT THROUGH NEXT WED DUE TO THE
BETTER TROPICAL MOISTURE VALUES REMAINING POSITIONED JUST
OFFSHORE.

1000-500 MB THICKNESS VALUES WILL START TO INCREASE STEADLY
THROUGH DAY 7 ALLOWING THE HIGH TEMPS TO WARM SOMEWHAT. HOWEVER
RECENT RAINFALL OVER THE REGION WILL TEND TO LIMIT THE WARMUP DUE
TO THE HIGHER SOIL MOISTURE VALUES.

THE ECMWF AND GFS MEX MOS GUIDANCE ARE IN PRETTY GOOD AGREEMENT
FOR BOTH POPS AND TEMPS THROUGH DAY 7. 500 MB HEIGHTS FIELDS
COMPARISONS BETWEEN THE GFS AND THE ECMWF THROUGH NEXT FRIDAY
INDICATE PRETTY GOOD AGREEMENT IN THE PLACEMENT OF THE 500 MB
RIDGE AXIS OVER TX AND MEXICO AND THE BROAD TROFFING OVER THE GULF
OF MEX. RUN TO RUN CONSISTENCY WITH THE GFS MEX MOS TEMPS AND POPS
ARE PRETTY STABLE. SO OVERALL CONFIDENCE IN THE LONGER RANGE MODEL
GUIDANCE IS ABOVE AVERAGE AT THIS TIME. WILL GO WITH A GENERAL
50/50 MODEL BLEND FOR BOTH TEMPS AND POPS IN THE LONGER TERM
PERIOD.

MARINE...TODAY THROUGH FRIDAY...LITTLE CHANGE IN THE SHORT TERM AS
HIGH PRESSURE REMAINS IN PLACE OVER THE NORTHWEST GULF...WITH
SLIGHTLY LOWER PRESSURE TO THE SOUTH AND INLAND. THE RESULT WILL
BE LIGHT TO MODERATE SOUTH SOUTHEAST WINDS AND LOW TO MODERATE
SEAS. THERE WILL BE LITTLE RELIEF FROM ISOLATED TO SCATTERED
SHOWERS AND TSTMS IN THE SHORT TERM HOWEVER...WITH A MID LEVEL LOW
APPROXIMATELY OVERHEAD.

FRIDAY NIGHT THROUGH SUNDAY...BROAD SURFACE RIDGING OVER THE GULF
OF MEX AND THE TX COASTLINE WILL MAINTAIN LIGHT TO MODERATE S-SE
SURFACE WINDS FOR BOTH THE BAY AND GULF WATERS. THE GULF SWELLS
WILL REMAIN FAIRLY LOW DUE TO THE WEAKER SURFACE FLOW. NO SCA
CONDITIONS EXPECTED THROUGH SUNDAY. THE LATEST TROPICAL WEATHER
OUTLOOK FROM NHC DISCUSSES TS FRED IN THE ATLANTIC AND A TROPICAL
WAVE MOVING OFF OF THE WEST COAST OF AFRICA. THE GULF OF MEX
AND THE CARIB SEA REMAIN CLEAR OF TROPICAL ACTIVITY AT THIS TIME.

&&

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

$$

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