Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 290549 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1249 AM CDT MON JUN 29 2015

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

&&

.AVIATION...A FEW PASSING LOW CLOUDS ALONG WITH SOME HIGH LEVEL
CLOUDINESS OVERHEAD PREVAILS ACROSS DEEP SOUTH TEXAS EARLY THIS
MORNING. MVFR CONDITIONS MAY DEVELOP AROUND SUNRISE...SO WILL
CONTINUE TO MENTION A TEMPO AT ALL VALLEY TAF SITES BETWEEN 11-13Z
DUE TO LOWER CEILINGS AND VISIBILITIES. OTHERWISE...VFR CONDITIONS
EXPECTED FOR THE NEXT 24 HOURS. LIGHT WINDS OVERNIGHT WILL BECOME
MODERATE BY LATE MORNING WITH GUSTS AROUND 20 KNOTS IN THE
AFTERNOON.

&&

.PREV DISCUSSION... /ISSUED 618 PM CDT SUN JUN 28 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...ONLY CHANGES NEEDED TO THE PREVIOUS SET OF TAFS WAS
TO INITIAL CONDITIONS. RELEVANT PORTIONS OF PREVIOUS DISCUSSION
FOLLOW:

VFR THROUGH MUCH OF THE EVENING AND OVERNIGHT WITH A LOW
PROBABILITY OF MVFR CIGS AND VSBY AROUND SUNRISE MONDAY.
CONVECTIVE PROBABILITIES LOWER MONDAY AND SHOULD FAVOR THE
IMMEDIATE COASTAL REGIONS. LIGHT TO MODERATE SOUTH TO SOUTHEAST
WINDS TODAY AND MONDAY WITH SOME GUSTS UP TO 20 KNOTS MONDAY
LATE MORNING AND AFTERNOON.

PREV DISCUSSION... /ISSUED 256 PM CDT SUN JUN 28 2015/

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...TODAY`S CONVECTION
CONTINUES TO WANE AS IT TRACKS NORTH TO NORTHWEST. A SURGE OF
MOISTURE FROM THE BAY OF CAMPECHE COMBINING WITH DAYTIME HEATING
AND A WEAKLY CAP ATMOSPHERE AND THE CONTINUED 50H WEAKNESS ALOFT
WAS SUFFICIENT FOR THE EARLY DAY THUNDERSTORMS. AS WE MOVE INTO
TONIGHT THE LOST OF HEATING SHOULD ALLOW FOR ALL INLAND CONVECTION
TO DISSIPATE. SOUTHERLY FLOW INCREASING SLIGHTLY OVER THE COASTAL
WATERS OVERNIGHT MIGHT ALLOW FOR A FEW STREAMERS TO DEVELOP BELOW
THE INVERSION WITH ANY CONVECTION IMPACTING ONLY THE COASTAL
WATERS AND POSSIBLY LOWER CAMERON.

MODELS HAVE BEEN CONSISTENT FOR SEVERAL DAYS IN DRYING OUT A 800-
600MB LAYER MONDAY WITH A BIT MORE S-SSW FLOW. THIS WARMS UP THE THE
MID LAYER ENOUGH TO PLACE A SLIGHTLY STRONGER CAP ACROSS THE REGION
ESPECIALLY WEST OF 69E. THE MID LAYER WEAKNESS OR LOW PRESSURE
TROUGH REMAINS OVER THE REGION SO WILL NOT DROP ALL POPS BUT HAVE
SCALED BACK ON THE COVERAGE OF THE SLIGHT CHANCE POPS ALONG AND EAST
OF HIGHWAY 69E MONDAY AFTERNOON. AS WE WORK INTO MONDAY NIGHT
ANOTHER SURGE OF MOISTURE BEGINS TO WORK NORTHWARD AFTER MIDNIGHT AS
THE MID LAYER 50H STRENGTHENS AND ENHANCES THE SOUTHERLY FLOW
BETWEEN THE MEAN RIDGE OVER THE EASTERN GULF. HAVE INCREASED POPS
OVER THE COASTAL WATERS AND THE LOWER VALLEY AFTER MIDNIGHT WITH THE
MAJORITY OF THE MOISTURE WORKING ITS WAY NORTH DURING THE BEGINNING
OF THE LONG TERM.

SEASONAL TEMPERATURES CONTINUE WITH LITTLE DAY TO DAY VARIATION.
MODELS GUIDANCE REMAINS WITHIN A FEW DEGREES OF EACH OTHER SO LITTLE
CHANGE IN OVERALL FORECAST HIGHS AND LOW. THE LOWER RAIN CHANCES ON
MONDAY MAY ALLOW FOR TEMPERATURES TO PEAK A DEGREE OR TWO MORE THEN
TODAY.

LONG TERM /TUESDAY THROUGH SUNDAY/...FOR MOST OF THE LONG TERM
PERIOD THE WEATHER PATTERN WILL BE DOMINATED BY BROAD HIGH PRESSURE
OVER THE GREAT BASIN AND A BERMUDA HIGH ACROSS CENTRAL GULF OF MEXICO
EXTENDING TOWARDS THE EAST INTO THE SE COAST. THE SOUTH TEXAS REGION
WILL BE IN BETWEEN THIS TWO AREAS OF HIGH PRESSURE WITH DEEP TROPICAL
MOISTURE SURGING NORTHWARD OVER MEXICO AND DEEP SOUTH TEXAS THROUGH
THE PERIOD. THE LATEST 1000 TO 850 MB RH VALUES RANGE 75 TO 80 PERCENT
AS A PLUME OF DEEP TROPICAL MOISTURE MAKES ITS WAY ACROSS THE CWA TUE.
EXPECT ISOLATED ACTIVITY EARLY IN THE DAY BECOMING MORE WIDESPREAD IN
THE AFTERNOON HOURS AND PROGRESSING WEST INTO TUESDAY NIGHT. DUE TO
THE ABUNDANCE OF CLOUD COVER AND SLIGHT COOLING FROM THE CONVECTION...
HIGHS WILL BE BETWEEN THE MID 90S ALONG THE WESTERN COUNTIES AND
LOW 90S ALONG THE COAST. THIS SAME TREND FOLLOWS THROUGH THE WEEK
WITH A FEW BREAKS IN THE OVERNIGHT HOURS WITH A SLIGHT CHANCE OF
20 PERCENT WITH VERY ISOLATED SHOWERS. ENOUGH CONVECTION IS
EXPECTED THAT IT SHOULD BE ENOUGH FILTERED SUNSHINE TO PUSH
TEMPERATURES CLOSE TO SEASONAL NORMALS...MID TO UPPER 90S INLAND
AND LOWER 90S NEAR THE COAST.

IN GENERAL...THIS FAVORS A CONTINUED DIURNAL PATTERN OF MAINLY
OVERNIGHT/MORNING ACTIVITY OVER THE GULF...MORNING/EARLY
AFTERNOON ACTIVITY ALONG AND EAST OF U.S. 77...AND AFTERNOON INTO
EARLY EVENING ACTIVITY ELSEWHERE. EXACTLY WHICH DAY WILL BE
WETTEST REMAINS TO BE SEEN. MODEL STATISTICAL GUIDANCE FOCUSES ON
WEDNESDAY BUT RAW DATA SUGGEST THURSDAY COULD BE THE DAY AS WELL.
A FINAL NUGGET OF POSSIBLE INTEREST IS THE DEVELOPMENT OF A 35-40
KNOT SOUTHERLY 850 MB JET OVER STARR...ZAPATA...JIM HOGG...WHICH
COULD FOCUS SOME HEAVY RAINS ALONG THE RIO GRANDE AND OUT TOWARD
THE SIERRA MADRE...SOMETHING TO KEEP AN EYE ON AS THE WEEK
PROGRESSES.

MARINE.../TONIGHT THROUGH MONDAY NIGHT...BROAD SURFACE HIGH PRESSURE
OVER THE NORTHERN GULF WITH ITS CENTER ANCORED OVER THE NORTHEAST
GULF TO COMBINE WITH WITH A WEAK LOW PRESSURE TROUGH SITUATED OVER
THE SOUTHWEST GULF TO MAINTAIN A LIGHT TO MODERATE SOUTHEAST FLOW
AND A SLIGHT SEA THROUGH MONDAY AFTERNOON. THE LOW PRESSURE TROUGH
STRENGTHENS SLIGHTLY MONDAY NIGHT WITH THE GRADIENT TIGHTENING
INCREASING WINDS AND SEAS SLIGHTLY. AN ISOLATED SHOWER OR
THUNDERSTORMS WILL BE POSSIBLE.

TUESDAY THROUGH THURSDAY...MAINLY ISOLATED TO SCATTERED OVERNIGHT/
MORNING SHOWERS AND STORMS TUESDAY THROUGH THURSDAY...AND ACTIVITY
LIKELY TO CONTINUE FOR MOST WATERS INTO THE AFTERNOON BEYOND 5-10
NM FROM THE SHORE. SOUTHEAST WINDS WILL PREVAIL WITH SOME INCREASE
IN THE AFTERNOON AS THE GRADIENT STRENGTHENS WITH POSSIBLE SCEC
AND CONTINUE THROUGH THE END OF THE PERIOD.

&&

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

$$

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