Area Forecast Discussion
Issued by NWS Brownsville, TX

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FXUS64 KBRO 301944
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
244 PM CDT SAT APR 30 2016

.SHORT TERM /NOW THROUGH SUNDAY NIGHT/...FORECAST PANNING OUT AS
EXPECTED WITH THE MORNING UPDATE...AS THE PATCH OF LIGHT RAIN THAT
TOUCHED BROWNSVILLE LONG DEPARTED JUST AFTER NOON WITH A SCATTERED
CUMULUS SHIELD ACROSS THE VALLEY AND EASTERN RANCHLANDS AND A DRY
LINE SEEPING INTO THE RIO GRANDE PLAINS WITH PURE SUNSHINE. THE
NORTHERLY WIND SHIFT...THOUGH TEMPORARY...HAS REDUCED THE HAZE FOR
ALL BUT THE LOWER TEXAS COAST. PLENTY HOT WITH HEAT INDEX LIKELY
TO PUSH INTO THE 105-108 RANGE FOR MOST OF THE POPULATION THIS
AFTERNOON.

BY LATE AFTERNOON...SEA BREEZE KICKS WINDS AROUND TO THE EAST
WHICH WILL CUT OFF THE HEATING NEAR THE COAST BUT WITH GULF
TEMPERATURES OUTSIDE OF ANY LOCAL UPWELLING AREAS NEARING 80
EXPECT NO IMPACTS.

FOR THE OVERNIGHT...LIGHT EAST TO SOUTHEAST WINDS CONTINUE AND
SHOULD BE ENOUGH TO FAVOR A RETURN OF LOW CLOUDS VS. THICK FOG.
WILL ADD PATCHY FOG TO THE FORECAST TO COVER IT. ANOTHER VERY
STICKY NIGHT WITH TEMPERATURES HELD UP BY LOW CEILINGS...MID TO
UPPER 70S JUST ABOUT EVERYWHERE.

SUNDAY WILL DAWN MURKY ONCE AGAIN...BUT LOW TO VERY LOW HUMIDITY
ABOVE 850 MB BY MIDDAY SHOULD CLEAR THINGS OUT AND LEAVE NOTHING
MORE THAN FAIR WEATHER CUMULUS...WITH PERHAPS SOME PATCHY HIGH
CLOUDS SHOWING UP LATE. THE AMPLE SUNSHINE AND STILL HOT ATMS
WILL SUPPORT LOW TO MID 90S JUST ABOUT EVERYWHERE...AND DEWPOINTS
MAINLY EAST OF U.S. 281 WILL PUSH HEAT INDEX VALUES CLOSE TO OR
ABOVE 105 ONCE AGAIN EXCEPT NEAR THE COAST WHERE EASTERLY FLOW
WILL KEEP THINGS MORE IN CONTROL.

SPEAKING OF THOSE EASTERLY WINDS...THEY WILL CONTINUE TO KEEP A
GOOD TIDAL PUSH UP TO THE BASE OF THE DUNES PARTICULARLY WHERE THE
BEACH IS THINNED OR HAS NOT BEEN `RENOURISHED` WHICH INCLUDES MOST
NORTH END BEACHES FROM ACCESS 4 UP...BUT HAS ALSO PUSHED SETUPS
BACK TOWARD THE DUNE LINE AT CITY BEACHES AS WELL. THIS IS MOST
COMMON DURING THE MIDDAY TIDE CYCLE AND WILL BE A FACTOR FOR
BEACHGOERS BETWEEN 10 AM AND 3 PM SUNDAY (HIGH TIDE IS 1227 PM).
TIDAL DEPARTURES REACHED 1.4 FEET (ABOVE PREDICTED) AT HIGH TIDE
TODAY...AND SEE NO REASON THIS WON`T BE THE CASE SUNDAY EVEN THOUGH
PREDICTED TIDES SLIDE DOWN A LITTLE BIT.

IT GOES WITHOUT SAYING THAT EVEN THOUGH WIND SPEEDS ARE LOWER
EAST OF THE LOWER TEXAS WATERS...THERE WILL STILL BE ENOUGH GOING
(15 KNOTS OR SO) INTO SUNDAY TO REDIRECT LONGSHORE CURRENTS TO A
PERPENDICULAR OR RIP CURRENT ISSUE.  FOR EACH REASON...THE COASTAL
FLOOD STATEMENT/RIP CURRENT STATEMENT REMAINS IN EFFECT GIVEN THE
SWELLING CROWDS WITH THE HOT/HUMID WEATHER ACROSS THE VALLEY THIS
WEEKEND.

FOR SUNDAY NIGHT...SHEAR ENERGY AT 500 MB BEGINS TO RIDE ALONG THE
MORE PRONOUNCED FRONT THAT OOZES TOWARD THE RANCHLANDS BY THE END
OF THE PERIOD. THE VALLEY SHOULD STEER CLEAR OF MENTIONABLE
PRECIPITATION THROUGH THE NIGHT...BUT WILL HOLD ONTO LOW CHANCES
ACROSS THE RANCHLANDS FOR THE LAST SIX HOURS OF THE PERIOD. AS FOR
SEVERE WEATHER? STILL A LITTLE EARLY TO DETERMINE IF THE ENERGY
AND MEAN FLOW PATTERN DESTABILIZES TO SUPPORT A QLCS-TYPE
STRUCTURE INTO THE SOUTH TEXAS BRUSH COUNTRY AFTER MIDNIGHT SUNDAY
BUT THE POTENTIAL IS THERE...AS IS A PRETTY ROBUST CAP. SHOULD
SUCH A SYSTEM DEVELOP MOMENTUM COULD CARRY IT INTO THE DEEP SOUTH
TEXAS BRUSH COUNTRY. FOR NOW...WILL KEEP A TIGHT GRADIENT OF 20/30
UP THERE BUT REMOVE MENTIONABLE RAIN FOR THE VALLEY.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...A BROAD 500MB TROUGH
STRETCHING ACROSS THE SOUTHWEST UNITED STATES AND INTO THE CENTRAL
PLAINS WILL SUPPORT SOUTHWEST MID LEVEL FLOW OVER THE LOCAL AREA
ON SUNDAY. SPC PLACES MUCH OF SOUTH TEXAS IN A A MARGINAL RISK OF
SEVERE WEATHER CATEGORY...AS A WEAK FRONT SAGS SOUTH ACROSS TEXAS
DURING THE DAY. SOME CONVECTION MAY INITIATE OVER THE MEXICAN
MOUNTAINS TO THE SOUTH LATE SUNDAY AND THEN HEAD TOWARD THE RIO
GRANDE.

SURFACE HIGH PRESSURE WILL SUNSEQUENTLY MOVE SOUTH ALONG THE
FRONT RANGE OF ROCKIES SUNDAY INTO MONDAY...PUSHING A COLD FRONT
THROUGH DEEP SOUTH TEXAS AND THE RIO GRANDE VALLEY MONDAY INTO
MONDAY NIGHT. ONSHORE FLOW AT THE SURFACE WILL ALLOW MOISTURE TO
MOVE INTO THE REGION ON MONDAY AHEAD OF THE APPROACHING FRONT. SPC
HAS A NARROWER AREA OF THE MARGINAL RISK CATEGORY PAINTED ALONG
SOUTHEAST TEXAS AND DEEP SOUTH TEXAS FOR MONDAY...AND THAT IS
WHEN/WHERE THE BETTER CHANCES OF WEATHER WILL EVOLVE.

THE LATEST ECMWF/GFS ARE IN PRETTY GOOD AGREEMENT ON THE TIMING
OF THE PASSAGE OF THE LATE MONDAY COLD FRONT. BOTH LONG RANGE
MODELS SUGGEST THAT THE BEST LIFT/CHANCE OF STRONGER CONVECTION
WILL BE MONDAY AFTERNOON AND EVE. ONSHORE...IF NOT SOUTHEAST...
SURFACE FLOW WILL MORE OR LESS CONTINUESUNDAY IN SPITE OF THE
FIRST FRONT... ALLOWING ABUNDANT MOISTURE TOREMAIN IN PLACE ON
MONDAY AHEAD OF THE NEXT COLD FRONT. A FEW TENTHS OF AN INCH OF
RAIN WILL BE POSSIBLE ON MONDAY AS SURFACE HIGH PRESSBEGINS TO
PENETRATE INTO THE AREA... PROVIDING WEAK THOUGH IMPORTANT LOW
LEVEL LIFT. RAIN CHANCES WILL LINGER INTO TUESDAY HOWEVER...
ESPECIALLY ACROSS THE SOUTHERN PORTIONS OF DEEP SOUTH TEXAS.

THE MAIN THREATS IN A MARGINAL RISK CATEGORY ARE HAIL TO THE SIZE
OF A QUARTER AND STRONG GUSTY WINDS OF 40 TO 60 MPH. LOCALLY HEAVY
RAINFALL WILL ALSO BE POSSIBLE WITH SOME OF THE STORMS MONDAY AND
MONDAY NIGHT. DRIER AIR WILL FILTER INTO THE REGION TUESDAY NIGHT
INTO WEDNESDAY AS HIGH PRESS SPREADS OVER THE AREA. DRY CONDITIONS
WILL PREVAIL WEDNESDAY THROUGH FRIDAY.

ECMWF/GFS ARE IN REASONABLE AGREEMENT ON THE TIMING OF THE PASSAGE
OF THE LATE MONDAY COLD FRONT. BOTH SUGGEST THAT THE BEST LIFT/
CHANCE OF STRONGER CONVECTION WILL BE LATE MONDAY OR EVEN MONDAY
NIGHT. BOTH MODELS HANG ON TO RAIN CHANCES INTO TUESDAY...THOUGH THE
ECMWF COVERAGE/AMOUNTS IN THE MODEL SEEM A BIT MORE ROBUST THROUGH
TUESDAY. RAIN CHANCES WILL BE PALPABLE MONDAY THROUGH TUESDAY AS
MOISTURE POOLS ACROSS THE AREA. DRIER AIR WILL FILTER INTO THE
REGION TUESDAY NIGHT INTO WEDNESDAY AS HIGH PRESSURE SPREADS OVER
THE AREA.


&&

.MARINE...
NOW THROUGH SUNDAY NIGHT...THE LIGHTER WINDS FROM THE WEAK
BOUNDARY THIS MORNING REACHED THE GULF WATERS BUT AS MENTIONED BY
PREVIOUS SHIFT WILL NEED TO KEEP EYE ON WHETHER ANY SWELLS WELL
EAST OF THE WATERS CAN EDGE WESTWARD OVERNIGHT. CURRENT THINKING
IS THE GRADIENT WEAKENS JUST ENOUGH ACROSS THE CENTRAL GULF TO
KEEP NOTABLE SEAS BUT CLOSER TO 6 FEET. FOR NOW WILL ADVERTISE
"CAUTION FOR SEAS" THROUGH THE NIGHT AND PROBABLY INTO SUNDAY.
OTHERWISE...EAST/SOUTHEAST WINDS WILL REMAIN IN THE 10 TO 15 KNOT
RANGE OVERNIGHT AND PICK UP SUNDAY INTO SUNDAY EVENING BEFORE
SLOWLY DIMINISHING TOWARD DAYBREAK AS THE FRONT EDGES CLOSER TO
THE WATERS.

MONDAY THROUGH WEDNESDAY...LIGHT SOUTHEAST WINDS IN THE MORNING
WILL GIVE WAY TO STRENGTHENING NORTHEAST WINDS BEHIND A COLD FRONT
LATER IN THE DAY. SMALL CARAFT ADVISORY CONDITIONS WILL LIKELY
DEVELOP MONDAY NIGHT WITH 20 TO 25 KT NORTHEAST WINDS. WAVE
HEIGHTS WILL BUILD TO 5 TO 7 FEET. CONDITIONS WILL IMPROVE TUESDAY
THROUGH WEDNESDAY AS HIGH PRESSURE SPREADS OVER THE AREA AND
SHIFTS EAST. WINDS WILL VEER TO EAST OR SOUTHEAST WEDNESDAY NIGHT
INTO THURSDAY. UNSETTLED WEATHER WILL PREVAIL MONDAY THROUGH
WEDNESDAY AS A RESULT OF THE COLD FRONT. SCATTERED SHOWERS AND
THUNDERSTORMS WILL BE ON TAP MONDAY AND TUESDAY...BECOMING MORE
ISOLATED BY WEDNESDAY.

&&

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

GM...NONE.
&&

$$

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