Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 282333 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
633 PM CDT THU AUG 28 2014

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

&&

.AVIATION...COMPLICATED AVIATION FORECAST DUE TO THE PROXIMITY OF
THE BROAD TROPICAL STYLE LOW JUST OFFSHORE. WINDS HAVE SWITCHED
GENERALLY TO THE NORTHEAST...ALTHOUGH KBRO WENT FROM 360 AT THE
TOP OF THE HOUR TO 090 20 MINUTES LATER BECAUSE OF AN OUTFLOW
BOUNDARY DRIFTING IN FROM THE SOUTH. MOST AREAS WILL DECREASE TO
L/V OVERNIGHT. THE CENTER OF THE LOW PRESSURE WILL MOVE ASHORE
OVERNIGHT...ALLOWING THE MORE MOIST EASTERN SIDE TO MOVE INTO THE
EASTERN AIRPORTS. VCSH WILL CONTINUE FOR KHRL AND KBRO OVERNIGHT.
WITH MORE HEATING TOMORROW MORNING...EXPECT MORE WIDESPREAD
THUNDERSTORM ACTIVITY FOR THE REGION...ESPECIALLY ALONG THE COAST.

&&

.PREV DISCUSSION... /ISSUED 326 PM CDT THU AUG 28 2014/

SHORT TERM.../NOW THROUGH FRIDAY NIGHT/...LATEST WATER VAPOR AND
RADAR IMAGERY SHOWS A COMPACT CENTER EAST OF PORT MANSFIELD
GRADUALLY DRIFTING WEST/SOUTHWEST AS OF 1930Z. MOST OF THE
CONVECTION HAS INITIATED OVER THE NORTH CENTRAL PORTION OF THE CWA
AND IS MOVING SOUTHWEST AT AROUND 25 MPH. OVER THE GULF OF
MEXICO...MOST OF THE ACTIVITY HAS DIMINISHED COMPARED TO EARLY IN
THE MORNING HOURS BUT WE DO EXPECT THIS ACTIVITY TO REDEVELOP TONIGHT.
THE LOW PRESSURE AREA MOVES INLAND BY TONIGHT AND WITH IT AN
ABUNDANT AREA OF DEEP MOISTURE WILL CONTINUE TO SURGE INTO THE CWA
OVERNIGHT AND FRIDAY. THE LATEST 12Z KBRO SOUNDING SHOWS
PRECIPITABLE WATERS OF 2.30 INCHES AND RH VALUES FROM 1000 TO 500
MB INCREASING BETWEEN 70 TO 80 PERCENT RANGE. THIS WILL PROVIDE
ENOUGH MOISTURE AND UPPER LEVEL SUPPORT FOR MORE CONVECTION TO
DEVELOP OVERNIGHT AND THE EARLY MORNING HOURS FRIDAY. A BURST OF
CONVECTION THROUGH THE MORNING HOURS COULD PRODUCE MORE ORGANIZED
AND INTENSE AREAS OF RAINFALL. TOTAL RAINFALL ACCUMULATIONS TO RANGE
BETWEEN 1 TO 3 INCHES WITH THE STRONGEST STORMS WITH AREAS ALONG
AND EAST OF HWY 77. WIDESPREAD HEAVY RAIN IS NOT ANTICIPATED.
EASTERLY WINDS WILL BEGIN TO SHIFT MORE SOUTHEAST AS THE LOW MOVES
INLAND FRIDAY. TEMPERATURES WILL NOT BE AS WARM COMPARED TO
PREVIOUS DAYS DUE TO THE ABUNDANCE IN CLOUD COVER. EXPECT LOWS TO
REMAIN BETWEEN MID TO UPPER 70S. HIGHS WILL REMAIN BETWEEN THE MID
90S.

LONG TERM /SATURDAY THROUGH THURSDAY/..AT THE BEGINNING OF THE
LONG TERM A WEAK UPPER TROUGH RESIDES OVER THE WESTERN GULF COAST
WITH RIDGES ANCHORED OVER BOTH THE PACIFIC AND ATLANTIC COAST. THE
TROUGH WEAKENS SUNDAY INTO MONDAY WITH A ELONGATED RIDGE SETTING
UP ALONG THE NORTHERN GULF. FARTHER SOUTH WE WILL BE MONITORING A
TROPICAL WAVE MOVING WESTWARD ACROSS THE CARIBBEAN THIS WEEKEND
EMERGING INTO THE BAY OF CAMPECHE OR SOUTHERN GULF NEXT TUESDAY
AND WEDNESDAY.

SATURDAY...MOISTURE LEVELS TO REMAIN RATHER HIGH AND WITH THE UPPER
TROUGH/WEAKNESS OVER THE REGION THE CHANCE OF RAIN PERSIST. MODEL
GUIDANCE REMAINS CONSISTENT WITH MODERATE TO HIGH POPS. GIVEN THE
INSTABILITY AND ABUNDANT MOISTURE EXPECT ANOTHER ROUND OF DAYTIME
CONVECTION. TEMPERATURES TO CONTINUE JUST BELOW NORMALS WITH THE
ADDED MOISTURE.

SUNDAY AND LABOR DAY...AS THE TROUGH WEAKENS AND THE RIDGE BUILDS
THE ATMOSPHERE DRYS OUT GRADUALLY WITH PWATS FALLING BELOW 2 INCHES
MONDAY. SHOWERS BECOME MORE ISOLATED SUNDAY AND LIKELY FORM ALONG
THE SEA BREEZE. BEACH WEATHER LOOKS FINE FOR THE LATTER HALF OF
THE HOLIDAY WEEKEND WITH A LIGHT TO MODERATE ONSHORE WIND BUT RIP
CURRENT RISK IS LIKELY TO BE ELEVATED TO HIGH RISK AS A SWELL
TRAIN MAY DEVELOP WITH A TROPICAL WAVE MOVING INTO THE SOUTHEAST GULF.
AS THE ATMOSPHERE DRYS OUT TEMPERATURES TO RISE A FEW DEGREES.

TUESDAY THROUGH THURSDAY...THE TROPICAL WAVE OVER THE EAST CENTRAL
CARIBBEAN CONTINUES TO TRACK WESTWARD. CONDITIONS DO NOT APPEAR
FAVORABLE FOR THIS WAVE TO DEVELOP SIGNIFICANTLY. NHC CONTINUES TO
GIVE THIS DISTURBANCE A 20 PERCENT CHANCE OF TROPICAL CYCLONE
DEVELOPMENT THE NEXT 5 DAYS. DIFFERENCES CONTINUE BETWEEN THE GFS
AND ECMWF WITH GFS MAINTAINING SOME DEVELOPMENT INTO A TROPICAL
CYCLONE AS IT MOVES INTO THE SOUTHWESTERN GULF. ECMWF REMAINS
PERSISTENT MAINTAINING AN OPEN WAVE THROUGH ITS LIFE CYCLE OVER
THE TROPICS. IN ANY CASE BOTH MODELS SURGE TROPICAL MOISTURE INTO
SOUTH TEXAS AS EARLY AS TUESDAY. MODEL GUIDANCE POPS AS RESULT
CONTINUE IN THE 30-40 PERCENT WITH THE GOING FORECAST IN THE 20-30
PERCENT RANGE AT THIS TIME. NEAR NORMAL TEMPERATURES ARE EXPECTED.

MARINE...NOW THROUGH FRIDAY NIGHT...EASTERLY WINDS WILL REMAIN
BREEZE DUE TO THE CENTER OF THE LOW OVER THE GULF WATERS AND
DISORGANIZED ACTIVITY KEEPING ERRATIC AND GUSTY WINDS OVER THE
GULF WATERS. AT THIS TIME...SCEC CONDITIONS WILL PREVAIL THROUGH
THE DAY WITH SEAS BETWEEN 3 TO 5 FEET. DUE TO THE EASTERLY AND
PERPENDICULAR COMPONENT WITH THE COAST...EXPECT RIP CURRENTS TO
REMAIN HIGH THROUGH FRIDAY AFTERNOON. CONDITIONS WILL BE CLOSE
TO SCA BUT AT THIS TIME IT WILL REMAIN MARGINAL.

SATURDAY THROUGH TUESDAY...BROAD HIGH PRESSURE TO SETTLE OVER THE
NORTHERN GULF OF MEXICO THIS WEEKEND. A MODERATE ONSHORE FLOW
DEVELOPS SATURDAY AND PERSIST INTO SUNDAY. A TROPICAL WAVE OVER
THE CARIBBEAN TO MOVE ACROSS THE YUCATAN MONDAY AND EMERGE OVER
THE SOUTHERN GULF TUESDAY. THE PRESSURE GRADIENT BETWEEN THE WAVE
AND HIGH PRESSURE OVER THE NORTHERN GULF WILL TIGHTEN. AN
INCREASING FETCH OF EASTERLY WINDS TO ALLOW FOR A POSSIBLE LONG
PERIOD EASTERLY SWELL OVER THE OPEN GULF WATERS. SOME OF THIS
HIGHER SWELL WILL BE DIRECTED TOWARDS THE LOWER TEXAS COASTAL
WATERS MONDAY NIGHT INTO TUESDAY.

&&

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

GM...NONE.
&&

$$

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

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