Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 022343 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
643 PM CDT TUE SEP 2 2014

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

&&

.AVIATION...TROPICAL STORM DOLLY IS EXPECTED TO MAKE LANDFALL
LATER TONIGHT ABOUT 200 MILES SOUTH OF KBRO. RAIN BANDS ASSOCIATED
WITH THE TROPICAL STORM WILL MOVE EAST TO WEST ACROSS THE REGION
THROUGH WEDNESDAY AND BECOME MORE FREQUENT AND SLIGHTLY STRONGER
WITH EACH SUCCESSIVE BAND OVERNIGHT UNTIL THE STORM BEGINS TO
DISSIPATE OVER THE HIGHER TERRAIN OF MEXICO LATER WEDNESDAY. EXPECT
PREDOMINATE VFR WITH PREVAILING SHRA WITH TEMPO PERIODS OF GUSTY
WINDS UP TO 35 KNOTS AND MVFR CIGS AND VSBYS ESPEICALLY AS THE
RAIN BANDS BECOME MORE INTENSE AFTER MIDNIGHT AND EARLY WEDNESDAY.
ISOLATED THUNDER IS POSSIBLE BUT MORE DIFFICULT TO PINPOINT THE
BEST TIME WITH TROPICAL SYSTEMS.

&&

.PREV DISCUSSION... /ISSUED 244 PM CDT TUE SEP 2 2014/

SHORT TERM /NOW THROUGH WEDNESDAY NIGHT/...DOLLY IS HEADED
TOWARD LANDFALL THIS EVENING ABOUT 125 MILES SOUTH OF
BROWNSVILLE. THE MAIN FORECAST CHALLENGE WILL BE RAIN AMOUNTS.
MOST OF THE RAIN LOOKS LIKE IT WILL FALL SOUTH OF THE RIO
GRANDE...BUT PERIODS OF RAIN AND GUSTY SHOWERS WILL STILL OCCUR
ACROSS THE RGV AND DEEP SOUTH TEXAS TONIGHT INTO WED. CONVERGENT
BANDING TO THE NORTH OF THE CYCLONE AFTER IT MOVES INLAND WILL
PROVIDE THE BEST SHOT FOR RAIN LOCALLY... WITH INCREASING COVERAGE
ON WEDNESDAY...WHICH WILL BE THE PEAK. THE 12Z BRO SOUNDING SHOWS
A PRECIPITABLE WATER VALUE OF 2.16 INCHES WITH DEEP EAST FLOW.
MODEL GUIDANCE SUGGEST THAT PWAT VALUES ACROSS THE AREA WILL
GRADUALLY INCREASE TO TWO AND A QUARTER INCHES ON WED...COURTESY
OF TROPICAL STORM DOLLY. RAIN AMOUNTS COULD RANGE BETWEEN ONE AND
TWO INCHES ACROSS THE CWA THROUGH THE SHORT TERM PERIOD...WITH
ISOLATED LOCALLY HEAVY DOWNPOURS. IMPACTS WILL BE INCLUDE MAINLY
NUISANCE FLOODING...BUT A FOOT OR TWO OF WATER COULD ACCUMULATE
QUICKLY IN AREAS OF POOR DRAINAGE. ANY BREAKS IN THE SKY ALLOWING
FOR A PEAK AT THE SUN WEDNESDAY MAY ALLOW FOR A STRONGER
THUNDERSTORM OR TWO TO DEVELOP AND THUS THE POSSIBILITY OF A
TORNADO CAN NOT BE RULED OUT.

TODAY AND TONIGHT...THE 500MB RIDGE OVER THE SOUTHEAST WILL CONTINUE
TO INFLUENCE THE NORTHERN GULF OF MEXICO RESULTING IN TROPICAL STORM
DOLLY BEING DEFLECTED TOWARD THE NORTHEAST MEXICAN COAST. INCREASING
DEEP TROPICAL MOISTURE...LIGHT TO MODERATE ONSHORE FLOW AND DAYTIME
HEATING WILL SUPPORT SCATTERED MARINE SHOWER AND TSTM ACTIVITY FOR
TODAY...WITH MORE ISOLATED ACTIVITY OVER LAND. MINOR FLOODING OF
URBAN AREAS AND LOW LYING REGIONS COULD BE POSSIBLE LATER TODAY AND
TONIGHT...BUT MOST OF THE RAIN WILL BE SAVED UNTIL WEDNESDAY. CLOUD
COVER AND RAIN CHANCES WILL INCREASE THOUGH...KEEPING HIGH TEMPS
DOWN IN THE LOWER 90S...WITH LOW TEMPS TONIGHT IN THE MID TO UPPER
70S.

WEDNESDAY...DEEP TROPICAL MOISTURE AND INCREASING INSTABILITY WILL
RESULT IN SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. MINOR
FLOODING OF URBAN AND LOW LYING AREAS WILL AGAIN BE A CONCERN. HIGH
TEMPS WILL BE LOWER...POSSIBLY BEING HELD BELOW 90 FOR MANY AREAS
DUE TO THE INCREASE IN CLOUDS AND RAIN CHANCES.

WEDNESDAY NIGHT...SPORADIC SHOWER AND THUNDERSTORM ACTIVITY WILL
STILL BE POSSIBLE BUT A GENERAL LETUP WILL BE ON TAP AS DOLLY MOVES
INLAND AND WEAKENS. RAIN CHANCES WILL BE MORE FOCUSED OVER THE
MARINE AREAS AND UPRIVER OVER THE UPPER VALLEY. LOW TEMPS WILL BE IN
THE MID 70S.

LONG TERM /THURSDAY THROUGH MONDAY/...REMNANTS OF DOLLY CONTINUE
TO DISSIPATE ACROSS NORTHEAST MEXICO...WITH MOISTURE STILL
HANGING AROUND ACROSS SOUTH TEXAS. SHOWERS AND THUNDERSTORMS WILL
CONTINUE TO BE A THREAT THURSDAY INTO FRIDAY...MAINLY ALONG THE
SEABREEZE. AFTER FRIDAY...THE H5 RIDGE BEGINS TO BUILD SOUTHWARD
ACROSS TEXAS...INHIBITING THE CONVECTIVE FORMATION SOMEWHAT ACROSS
THE REGION. MODELS DIVERGE AFTER SATURDAY..WITH JUST ENOUGH
UNCERTAINTY BETWEEN THEM TO LOWER CONFIDENCE IN FORECAST FOR EARLY
NEXT WEEK. THE MIDLEVEL LOW THAT IS SWIRLING ABOVE THE BAHAMAS
WILL CONTINUE TO TREK WWD ACROSS FLORIDA INTO THE EASTERN GULF
OVER THE WEEKEND. THE FORECAST ISSUE IS WILL THIS FEATURE CONTINUE
WWD AND REACH THE WESTERN GULF EARLY NEXT WEEK...OR GET SLOWED
DOWN BY WEAK TROUGHING FROM THE NORTH. CURRENTLY LEANING TOWARD
THE LATTER SOLUTION OF THE ECMWF...WITH A DRIER FORECAST FOR
SUNDAY AND MONDAY.

MARINE...
NOW THROUGH WEDNESDAY NIGHT...WINDS AND WAVE HEIGHTS ON THE GULF
WATERS WILL INCREASE STEADILY THROUGH TONIGHT AND EARLY WEDNESDAY AS
TROPICAL STORM DOLLY APPROACHES THE NORTHEAST MEXICAN COAST AND THEN
MOVES INLAND. WINDS TO 25 KNOTS AND WAVE HEIGHTS OF UP TO 11 FEET
WILL BE POSSIBLE ON THE GULF WATERS EAST OF BROWNSVILLE AND THE CITY
OF SOUTH PADRE ISLAND THROUGH WEDNESDAY...BEFORE CONDITIONS IMPROVE.
TROPICAL SHOWER AND TSTM ACTIVITY WILL ALSO INCREASE...PRODUCING
CLOUD TO WATER LIGHTNING...GUSTY WINDS AND BRIEF HEAVY DOWNPOURS.
THESE ADVERSE CONDITIONS WILL HOLD THROUGH WEDNESDAY...WITH SOME
IMPROVEMENT WEDNESDAY NIGHT. CSTL CONDITIONS WILL ALSO BE HAZARDOUS
AND A COASTAL FLOOD ADVISORY...A HIGH SURF ADVISORY...AND A RIP
CURRENT STATEMENT HAVE BEEN ISSUED.

THURSDAY THROUGH SUNDAY...IMPROVING MARINE CONDITIONS THROUGH THE
EXTENDED PERIOD AS THE EFFECTS OF DOLLY WANE. THURSDAY SEAS OF 4
TO 5 FEET WILL BE LOWERING TO AROUND 2 FEET. WINDS WILL GENERALLY
REMAIN LIGHT AROUND 10 KNOTS THROUGH THE PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  79  86  80  89 /  70  70  40  40
BROWNSVILLE          78  86  78  90 /  70  70  40  40
HARLINGEN            78  87  78  90 /  70  70  40  40
MCALLEN              78  88  77  92 /  60  70  40  40
RIO GRANDE CITY      78  89  77  92 /  50  60  40  40
SOUTH PADRE ISLAND   80  85  81  86 /  70  70  40  40

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...HIGH RIP CURRENT RISK THROUGH WEDNESDAY EVENING FOR TXZ251-256-
     257.

     HIGH SURF ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR TXZ251-256-257.

     COASTAL FLOOD ADVISORY UNTIL 4 PM CDT WEDNESDAY FOR TXZ251-256-
     257.

GM...SMALL CRAFT ADVISORY UNTIL 7 PM CDT WEDNESDAY FOR GMZ150-155-170-
     175.

&&

$$

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