Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 071324 AAB
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
824 AM CDT MON JUL 7 2014

.DISCUSSION...MORNING SOUNDING SHOWS AN APPRECIABLE UPTICK IN SFC-
700MB RELATIVE HUMIDITY...PRESUMABLY ADVECTED IN ON SOUTHEASTERLY
WINDS OVERNIGHT FROM THE WESTERN GULF OF MEXICO. LAPS/RAP/NAM
PROJECTIONS ARE UNDERDONE BASED ON THE OBSERVED DATA AND AMSU/SSMI
BLENDED TOTAL PRECIPITABLE WATER ESTIMATES ARE CLOSER TO THE
OBSERVED PWAT THIS MORNING...WITH HIGHER LEVELS TO THE SOUTHEAST
WHERE WINDS WILL CONTINUE TO COME FROM THROUGH THE DAY. THE
PRIMARY LIMITING FACTOR TO PRECIP WILL BE INCREASING SOUTHEASTERLY
WINDS THAT WILL MAKE IT SLOWER/HARDER TO GET A STRONG SEABREEZE
BOUNDARY BUT THE RICH AND DEEP MOISTURE COUPLED WITH STRONG
HEATING DUE TO A LACK OF ANY MID AND UPPER LEVEL CLOUD COVER
SHOULD BE SUFFICIENT FOR ISOLATED TO SCATTERED SHOWER AND
THUNDERSTORM DEVELOPMENT IN 3 TO 4 HOURS. RAISED POPS TO EXPAND
THE SLIGHT CHANCE AND INTRODUCED CHANCE POPS THROUGH MUCH OF THE
SOUTHEASTERN HALF OF THE CWA. /68-JGG/

&&

.PREV DISCUSSION... /ISSUED 644 AM CDT MON JUL 7 2014/

DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW.

AVIATION...VFR CONDITIONS WILL PREVAIL ACROSS THE REGION FOR THE
NEXT 24 HOURS. MOSTLY CLEAR SKIES WITH LIGHT SOUTHEAST WINDS
EXPECTED NOW THROUGH MID MORNING. SOUTHEAST WINDS INCREASE AROUND
15Z WITH GUSTS UP TO 25 KNOTS POSSIBLE BY LATE MORNING INTO THE
AFTERNOON WITH SOME CIRRUS STREAMING ACROSS THE REGION. SOUTHEAST
WINDS BEGIN TO DECREASE AFTER SUNSET WITH MOSTLY CLEAR SKIES
DEVELOPING BY LATE EVENING.

PREV DISCUSSION... /ISSUED 332 AM CDT MON JUL 7 2014/

SHORT TERM /NOW THROUGH TUESDAY/...MID LEVEL WEAKNESS CONTINUES
ACROSS DEEP SOUTH TEXAS WITH 500 MB RIDGING ACROSS THE FOUR CORNER
STATES AND OFF THE FLORIDA ATLANTIC COAST. SURFACE HIGH PRESSURE
OVER THE GULF OF MEXICO WILL MAINTAIN LIGHT TO MODERATE SOUTHEAST
FLOW ACROSS THE AREA. 00Z BRO SOUNDING INDICATES DEEP SOUTH TO
SOUTHEAST FLOW UP TO OVER 15000 FEET WITH A PRECIPITABLE WATER VALUE
OF 1.66 INCHES. CURRENT BRO RADAR SHOWS SOME CONVECTION MOVING
NORTHWEST INTO THE EXTREME NORTHEAST COAST OF TAMAULIPAS EXTENDING
SOUTH OF THE LOWER TEXAS GULF WATERS. WILL MENTION A SLIGHT CHANCE
POPS THIS MORNING FOR THE VALLEY AND THE COASTAL COUNTIES DUE TO THE
ONGOING CONVECTION.

A SLIGHT CHANCE OF A DIURNAL SHOWERS OR THUNDERSTORMS CONTINUES FOR
LATER TODAY AND TUESDAY...WHICH IS A SCOSCHE ABOVE THE DRIER MODEL
GUIDANCE. THE SOUTHEASTERLY FLOW SHOULD KEEP MOST CONVECTION JUST
NORTH OF THE LOWER AND MID VALLEY. HIGH TEMPERATURES TODAY AND
TUESDAY WILL RANGE FROM THE UPPER 80S NEAR THE COAST TO THE MID TO
UPPER 90S ACROSS THE VALLEY AND NEAR 100 OVER THE WEST. OVERNIGHT
LOW TEMPERATURES TONIGHT WILL BE GENERALLY IN THE MID TO UPPER 70S.

LONG TERM /TUESDAY NIGHT THROUGH SUNDAY NIGHT/...THE OVERALL
PATTERN WILL EVOLVE SLOWLY...WITH RIDGING BOTH UPSTREAM OVER THE
SOUTHWEST UNITED STATES AND DOWNSTREAM OVER THE EASTERN ATLANTIC
STUBBORNLY HANGING ON WHILE A SLIGHT WEAKNESS OVER THE WEST GULF...
ONLY A FEW DECAMETERS LOWER IN HEIGHT THAN THE RIDGES ON EITHER
SIDE...STARTS OFF THE LONG TERM. BOTH THE ECMWF AND THE GFS TAKE THE
WEAKNESS INTO MEXICO OVER TIME...WHILE TRYING TO FILL IN THE RIDGE
ACROSS THE ENTIRE GULF AROUND MID WEEK. IN DOING SO...A BURST OF
CONVECTIVE ACTIVITY WILL DEVELOP OVER THE SOUTHWEST GULF AROUND MID
WEEK...WHICH WILL BUMP POP CHANCES UP SLIGHTLY. BOTH MODELS SHOW 24
HOUR POPS IN THE 40 PERCENT AREA ON THURSDAY...BUT THE 12 HOUR POPS
ARE NOT NEARLY AS IMPRESSIVE AND ONLY 20 TO 30 PERCENT ARE INDICATED
IN THE FORECAST. CLOUDIER SKIES WILL REIGN FROM WEDNESDAY THROUGH
FRIDAY HOWEVER...DUE IN PART TO THE MORE UNSETTLED CONDITIONS IN THE
SOUTHWEST GULF. TEMPERATURE WISE...READINGS WILL BE PRETTY CLOSE TO
NORMAL...WITHIN A COUPLE OF DEGREES. WITH THE PATTERN CHANGING SO
SLOWLY...NO REAL BIG CHANGES WERE NEEDED TO THE INHERITED FORECAST.
RELIED A LOT ON THE PERSISTENCE CARD...WHILE REFRESHING MOSTLY
DAYS 3 THROUGH 5 FOR NEW MODEL DATA. BY THE WEEKEND...BROAD RIDGING
ALOFT WILL STRETCH ACROSS A LARGE GEOGRAPHIC AREA INCLUDING TEXAS
AND THE NORTH GULF. THIS WILL BRING LOWER RAIN CHANCES ALONG WITH A
HIGHER AMOUNT OF SUN AND SLIGHTLY WARMER...POSSIBLY EDGING A FEW
DEGREES ABOVE NORMAL...DAYTIME HIGH TEMPERATURES.

MARINE...
NOW THROUGH TUESDAY...BUOY 42020 REPORTED SOUTH-SOUTHEAST WINDS
AROUND 10 KNOTS WITH GUST OF 12 KNOTS AND SEAS OF 1.6 FEET AT 0150
AM CST/0650 UTC. LIGHT TO MODERATE SOUTHEAST WINDS AND LOW SEAS WILL
PREVAIL ACROSS THE LOWER TEXAS COASTAL WATERS THROUGH THE PERIOD.
MARGINAL EXERCISE CAUTION LEVEL WINDS EXPECTED ON THE LAGUNA MADRE
THIS AFTERNOON AND AGAIN ON TUESDAY AFTERNOON. ISOLATED SHOWERS AND
THUNDERSTORMS POSSIBLE ALONG THE LOWER TEXAS COAST THROUGH TUESDAY.

TUESDAY NIGHT THROUGH FRIDAY NIGHT...A PERSISTENT MID LEVEL WEAKNESS
OVER THE WEST GULF WILL SURVIVE INTO THE BEGINNING OF THE LONG TERM
WITH MID LEVEL RIDGING ON EITHER SIDE...OVER THE SOUTHWEST UNITED
STATES AND ALSO OVER BERMUDA...WITH SURFACE HIGH PRESSURE STRETCHING
WEST FROM THE EAST ATLANTIC INTO AND ACROSS THE GULF. THE RESULT
WILL BE AN INITIAL CONTINUATION OF GENERAL MODERATE SOUTHEAST WINDS
AND MODERATE SEAS. AS THE WEEK PROGRESSES HOWEVER...ATLANTIC RIDGING
WILL STRENGTHEN AND WILL PUSH HIGH PRESSURE MORE DEFINITIVELY INTO
THE GULF...WHILE MID LEVEL WEAKNESS OVER THE WEST GULF WILL FADE
WEST INTO MEXICO. IN THE MEAN TIME...UNSETTLED WEATHER WILL DEVELOP
TO THE SOUTH ONCE AGAIN...RESULTING IN EXTRA SHOWERS MOVING NORTH
FROM WEDNESDAY THROUGH FRIDAY. SMALL CRAFT SHOULD EXERCISE CAUTION
CONDITIONS MAY DEVELOP AT TIMES EARLY IN THE LONG TERM...WITH WINDS
AROUND 15 KNOTS...AS HIGH PRESSURE BUILDS INTO THE WEST GULF.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  91  78  91  79 /  30  10  10  10
BROWNSVILLE          94  77  94  78 /  30  10  10  10
HARLINGEN            95  76  95  77 /  30  10  10  10
MCALLEN              97  77  97  77 /  30  10  20  10
RIO GRANDE CITY      97  76  97  76 /  20  10  10  10
SOUTH PADRE ISLAND   88  79  88  80 /  20  20  20  10

&&

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

$$

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