841
FXUS64 KBRO 220001 AAA
AFDBRO
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
701 PM CDT THU OCT 21 2021
DISCUSSION
UPDATED FOR LATEST AVIATION DISCUSSION BELOW.
AVIATION
THE AFTERNOON SEA BREEZE HAS CLEARED THE RGV AND IS
PRODUCING ONLY SOME ISOLD CONV OVER ZAPATA COUNTY. SO EXPECT THE
SHORT TERM TO REMAIN RAIN FREE FOR THE TIME BEING. THE SURFACE
WINDS WILL DECREASE LATER TONIGHT WHICH WILL COMBINE WITH THE
ELEVATED SURFACE DEWPOINTS TO ALLOW FOR SOME INCREASED POTENTIAL
FOR FOG FORMATION ACROSS MAINLY THE NORTHERN RANCHLANDS LATER
TONIGHT INTO FRI MORNING. SOME OF THIS MAY CREEP INTO THE RGV
IMPACTING THE AIRPORTS FOR A COUPLE OF HOURS TOMORROW MORNING
POSSIBLY RESULTING IN SOME MVFR/IFR VSBYS. THIS SHOULD BE PRETTY
SHORT LIVED AFTER SUNRISE WITH INCREASING DAYTIME HEATING. THE SEA
BREEZE TOMORROW MAY FIRE UP SOME AFTERNOON CONV IN THE BRO AREA
AND WILL INCLUDE A PROB30 GROUP DURING THE AFTERNOON HOURS.
PREV DISCUSSION
/ISSUED 307 PM CDT THU OCT 21 2021/
SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT): QUASI-ZONAL MID-LEVEL
FLOW WILL PERSIST THROUGH MUCH OF THE SHORT-TERM PERIOD. TONIGHT
SHOULD BE MOSTLY CLEAR TO PARTLY CLOUDY, WITH GENERALLY A DRY AND
STABLE ATMOSPHERE IN PLACE. HOWEVER, LATEST RUN OF THE HRRR WAS
INDICATING SHOWERS/STORMS DEVELOPING JUST SOUTH OF THE RIVER LATE
THIS AFTERNOON OR EARLY THIS EVENING, THEN DISSIPATING BEFORE
CROSSING OVER INTO THE RGV. CURRENTLY KEPT POPS OUT OF THE
FORECAST TONIGHT, BUT WILL CONTINUE TO MONITOR TRENDS. OTHERWISE,
A FAIRLY INACTIVE NIGHT IS IN STORE WITH LOW TEMPERATURES DROPPING
INTO THE UPPER 60S OR LOWER 70S. PATCHY TO AREAS OF FOG MAY
DEVELOP AGAIN AFTER MIDNIGHT TONIGHT, MAINLY ACROSS THE NORTHERN
RANCHLANDS AND WESTERN PORTIONS OF THE CWA. AT THIS TIME, A DENSE
FOG ADVISORY IS NOT ANTICIPATED.
AS SURFACE RIDGING OVER THE PLAINS CONTINUES TO SLIDE SOUTHEAST OVER
THE LOWER MISSISSIPPI VALLEY OVER THE NEXT 24 HOURS, WINDS WILL
BEGIN TO VEER FROM EAST TO SOUTHEAST BY FRIDAY EVENING, BUT WILL
REMAIN GENERALLY LIGHT. CONDITIONS LOOK FAVORABLE FOR SEABREEZE
ACTIVITY TO GET GOING IN THE AFTERNOON, THOUGH STILL SOME
QUESTIONS REMAIN ON JUST HOW CONVECTIVELY ACTIVE THE SEABREEZE
WILL BE AS LOW TO MID-LEVEL DRY AIR BEGINS TO ERODE BY THE
AFTERNOON. WEAK SHORTWAVE TROUGHS EMBEDDED IN THE MID-LEVEL FLOW
MAY HELP TO ASSIST IN SHOWER DEVELOPMENT, MAINLY IN THE AFTERNOON.
SO, DECIDED TO KEEP IN 20-30% POPS FOR MOST INLAND LOCATIONS
TOMORROW IN THE FORM OF SPOTTY SHOWERS AND THUNDERSTORMS. SLIGHTLY
BETTER RAIN CHANCES WILL OCCUR FRIDAY NIGHT INTO SATURDAY
MORNING, ESPECIALLY NEAR THE COAST, AS A SHORTWAVE TROUGH SLIDES
CLOSER TO THE CWA. THERE IS STILL SOME UNCERTAINTY ON HOW FRIDAY
NIGHT WILL PLAY OUT, BUT WILL KEEP POPS GENERALLY 20-30% FRIDAY
NIGHT.
A COASTAL FLOOD ADVISORY REMAIN IN EFFECT BETWEEN 3 PM TODAY AND 4
AM FRIDAY MORNING. HIGH TIDE IS SCHEDULED TO OCCUR AT 6:17 PM CDT THIS
EVENING. AS OF THIS WRITING, WATER LEVELS AT SPI BRAZOS SANTIAGO
ARE STILL ABOUT 0.8 FEET ABOVE PREDICTED LEVELS (OBSERVED AT 0.68
FEET MHHW). MINOR FLOODING WILL BE POSSIBLE, ESPECIALLY ALONG
NARROW PARTS OF SPI AND BOCA CHICA BEACHES THIS EVENING AND
OVERNIGHT TONIGHT. ANOTHER COASTAL FLOOD ADVISORY MAY BE NEEDED
FOR FRIDAY AFTERNOON/EVENING.
LONG TERM (SATURDAY THROUGH THURSDAY): A NEARLY ZONAL FLOW WILL
PREVAIL OVER DEEP SOUTH TEXAS WITH THE WEEKEND AS A PAIR OF MODEST
SHORT WAVES TRANSVERSE OVER THE CWA IN THE MID TO UPPER LEVEL FLOW.
HOWEVER, RAIN CHANCES SHOULD REMAIN FAIRLY LIMITED AS PWATS BETWEEN
1.5 TO 1.7 INCHES WITH ISOLATED CONVECTION POSSIBLE OVER THE COASTAL
WATERS. RAIN CHANCES ARE EXPECTED TO INCREASE MONDAY INTO TUESDAY AS
DEEP TROPICAL MOISTURE SURGES INTO THE REGION. THE LATEST GFS
SUGGEST PWATS QUICKLY JUMP TO NEAR 2.4 INCHES, ESPECIALLY ALONG THE
COAST, BY MONDAY NIGHT. THE DEEP MOISTURE THEN SHIFTS NORTHEAST LATE
TUESDAY AS DRIER AIR FILTERS INTO THE AREA. A LARGE 500MB TROUGH
WILL SWING OVER THE PLAINS MID TO LATE WEEK PUSHING THE ASSOCIATED
COLD FRONT INTO DEEP SOUTH TEXAS BY LATE WEEK. ABOVE NORMAL
TEMPERATURES ARE EXPECTED THROUGH MUCH OF THE PERIOD, EXCEPT
TEMPERATURE MAY BE LOWER ON TUESDAY DUE TO INCREASE CLOUD COVER AND
RAIN CHANCES.
MARINE (NOW THROUGH FRIDAY NIGHT): BROAD SURFACE RIDGING OVER THE
GULF WILL KEEP MARINE CONDITIONS MOSTLY FAVORABLE THROUGH THE
SHORT TERM PERIOD. LIGHT TO MODERATE EAST/NORTHEAST WINDS WILL
GRADUALLY SHIFT SOUTHEASTERLY BY FRIDAY NIGHT. GULF SEAS WILL
LIKEWISE REMAIN TAME, WITH SIGNIFICANT WAVE HEIGHTS RANGING
BETWEEN 2 AND 3 FEET. SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE
BEGINNING ON FRIDAY AS WEAK SURFACE & MIDLEVEL TROUGHING
APPROACHES THE WATERS.
SATURDAY THROUGH TUESDAY...MODERATE ONSHORE FLOW AND LOW TO MODERATE
SEAS WILL PREVAIL ALONG THE LOWER TEXAS COAST THROUGH THE PERIOD.
HOWEVER, BRIEF PERIODS OF SMALL CRAFT EXERCISE CAUTION CONDITIONS
MAY BE POSSIBLE AT TIMES THIS WEEKEND.
PRELIMINARY POINT TEMPS/POPS
BAYVIEW/PORT ISABEL 71 85 73 87 / 10 30 20 20
BROWNSVILLE 71 89 73 89 / 10 30 20 20
HARLINGEN 68 89 71 89 / 10 20 20 20
MCALLEN 71 91 73 91 / 10 20 20 20
RIO GRANDE CITY 70 92 71 94 / 10 20 20 10
SOUTH PADRE ISLAND 77 82 78 83 / 10 30 20 20
BRO WATCHES/WARNINGS/ADVISORIES
TX...COASTAL FLOOD ADVISORY UNTIL 4 AM CDT FRIDAY FOR TXZ256-257-351.
GM...NONE.
THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT:
HTTPS://WEATHER.GOV/RGV
60-SPEECE/69-FARRIS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page