Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 281747
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
1247 PM CDT FRI AUG 28 2015

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

&&

.AVIATION...LATEST SATELLITE IMAGERY SHOWS CU FIELD DEVELOPING
ACROSS THE EASTERN HALF OF THE RIO GRANDE VALLEY AND DEEP SOUTH
TEXAS. VFR CONDITIONS ARE EXPECTED TO CONTINUE THROUGH MUCH OF THE
NEXT 24 HOURS WITH AN HOUR OR TWO OF MVFR CEILINGS POSSIBLE AROUND
DAYBREAK. LIGHT AND VARIABLE WINDS TONIGHT WILL BECOME
SOUTHEASTERLY AT AROUND 10 KNOTS BY LATE SATURDAY MORNING.

&&

.PREV DISCUSSION... /ISSUED 627 AM CDT FRI AUG 28 2015/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...VERY DRY AIR REMAINS IN PLACE OVER SOUTH TEXAS WITH
ONLY A FEW CLOUDS NEAR THE COAST TODAY. VFR CONDITOINS TO PREVAIL
TODAY AND TONIGHT. A LIGHT EAST WIND LESS WITH GUSTS AROUND 15
KNOTS IN THE AFTERNOON ARE EXPECTED.

PREV DISCUSSION... /ISSUED 402 AM CDT FRI AUG 28 2015/

SHORT TERM  /TODAY THROUGH SATURDAY/...IN ONE WORD DRY. 28/00Z
SOUNDING INDICATED PWAT OF 1 INCH WITH THE GFS BOTTOMING OUT AT 0.68
INCHES AT 29/00Z SATURDAY. IF THE GFS FORECAST IS CORRECT THIS WOULD
BE THE LOWEST PWAT RECORDED IN THE AUG SINCE RECORDS HAVE BEEN KEPT
SINCE 1948. NORTHEAST TO NORTH FLOW BETWEEN UPPER RIDGE TO OUR WEST
AND UPPER RIDGE TO OUR EAST TO MAINTAIN A 25KFT DEEP DRY LAYER WITH
AN AVERAGE RH OF 10 PERCENT. THIS DRY AIR TO MIX TO THE SURFACE WITH
AFTERNOON RH VALUES TANKING BETWEEN THE UPPER TEENS IN THE WEST TO
ABOUT 40 PERCENT ALONG THE COAST...PRETTY DARN DRY FOR LATE AUGUST.
DIURNAL TEMPERATURE RANGE WILL BE SIMILAR TO YESTERDAY ABOUT 20
DEGREE ALLOWING HIGH TEMPERATURES TO APPROACH LATE AUGUST NORMALS.

TONIGHT AND SATURDAY...DRY AIR CONTINUES IN PLACE BUT DEPTH BEGINS
TO NARROW WITH SOUTH TEXAS REMAINING BETWEEN THE WESTERN RIDGE AND
THE SLOW RETROGRADING TROUGH TO OUR EAST. A PLEASANT MILD NIGHT WILL
BE FOLLOWED BY ANOTHER FAIR WARM TO HOT DAY.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...MODELS BRINGING A
HIGH DEGREE OF SPREAD FOR THE EXTENDED PERIOD WITH REGARD TO THE
EVOLUTION OF THE EASTERN US TROUGH. THE GENERAL TROUGH IS EXPECTED
TO SLOWLY SPREAD WESTWARD INTO TEXAS EARLY NEXT WEEK. NOW THE MAIN
DIFFERENCE IN THE MODELS IS WHERE THE TROUGH GOES ONCE IT GETS
HERE. THE ECMWF CUTS THE TROUGH OFF AND PULLS IN SWWD UNDERNEATH
THE RIDGE...WHILE THE GFS CUTS THE LOW OFF OVER THE NW
GULF...KEEPING IT THERE THROUGH THE ENTIRE WEEK. IF THE ECMWF
SOLUTION VERIFIES...SOUTH TEXAS WILL BE ON THE WETTER EASTERN SIDE
OF THE TROUGH...BUT IF THE FORECAST LEANS MORE TOWARD THE
GFS...SOUTH TEXAS STAYS ON THE SUBSIDENT DRIER WESTERN SIDE. WILL
SIGNIFICANT UNCERTAINTY IN THE FORECAST...WILL HOLD ONTO SOME POPS
FOR MOST OF NEXT WEEK FOR THE WETTER SCENARIO...BUT KEEP RAIN
CHANCES LOW FOR NOW UNTIL CONSISTENCY IMPROVES.

MARINE...
NOW THROUGH SATURDAY...THE COASTAL WATER WILL CONTINUE TO
EXPERIENCE FAVORABLE MARINE CONDITIONS AS WEAK HIGH PRESSURE OVER
THE WESTERN GULF OF MEXICO PERSIST. A LIGHT EAST TO SOUTHEAST FLOW
AND A FLAT TO SLIGHT SEA CAN BE EXPECTED TODAY AND SATURDAY.

SUNDAY THROUGH WEDNESDAY...GRADIENT ACROSS THE NW GULF WILL REMAIN
RELAXED...KEEPING WINDS AND SEAS LOW. INCREASED SHOWER AND
THUNDERSTORM ACTIVITY IS EXPECTED EACH DAY.

&&

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

$$

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

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