Area Forecast Discussion
Issued by NWS Brownsville, TX

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000
FXUS64 KBRO 050850
AFDBRO

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BROWNSVILLE TX
350 AM CDT WED AUG 5 2015

.SHORT TERM  /TODAY THROUGH THURSDAY/...THE COMBINATION OF HIGH HEAT
AND HUMIDITY TO PRODUCE EXTREME HEAT INDICES THIS AFTERNOON AS WAS
THE CASE YESTERDAY. EVEN THOUGH MID LAYERS DRIED OUT WITH SUBSIDENCE
PROVIDED BY THE UPPER RIDGE CENTER OVER THE DESERT SOUTHWEST AND
WESTERN TEXAS LOW LEVEL DEW POINTS REMAINED HIGH ENOUGH TO COMBINE
WITH THE ABOVE NORMAL NEAR RECORD HEAT TO PRODUCE HEAT INDICES IN
THE RANGE OF 107 TO 114 DEGREES ALONG THE COASTAL COUNTIES AND ALONG
MOST OF THE COUNTIES THAT BORDER THE RIO GRANDE RIVER. THIS SHOULD
BE THE CASE TODAY AND AS A RESULT WILL ISSUE A HEAT ADVISORY FROM
NOON TO 6 PM. A RECORD HIGH TEMPERATURE OF 104 WAS TIED AT MCALLEN
YESTERDAY AS FOR TODAY RECORDS WILL BE CHALLENGED AT HARLINGEN AND
POSSIBLY MCALLEN AND NOT LIKELY AT BRO UNLESS WINDS BECOME MORE
SOUTHERLY THEN SOUTHEASTERLY.  THERMAL GRADIENT REMAINS MODERATELY
STRONG WITH BREEZY AND GUSTY WINDS ADDING TO MISERY OF THE HEAT THIS
AFTERNOON.

THE UPPER RIDGE AXIS EDGES EASTWARD TONIGHT AND THURSDAY WITH VERY
WARM OVERNIGHT LOWS AND ANOTHER SCORCHER ON THURSDAY. 850MB TEMPS
EDGE UP AROUND 0.5C WHICH WILL PROMPT SLIGHTLY HIGHER HIGHS. AS FOR
HEAT INDICES HUMIDITY LEVELS WILL BE ON THE EDGE ONCE AGAIN FOR
EXTREME HEAT AND WILL LOOK AGAIN TONIGHT TO EXTEND THE HEAT ADVISORY
FOR ANOTHER DAY. THE SOUTHEAST BREEZES TO PICK UP AGAIN AS THE
GRADIENT IS MAINTAINED BETWEEN THE LEE SIDE TROUGH OVER THE SIERRA
MADRE AND THE RELATIVELY COOLER GULF WATERS.

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...NOT MUCH CHANGE
EXPECTED THROUGH THE WEEKEND WITH MID LEVEL HIGH PRESSURE
STATIONED ACROSS NORTHERN AND EASTERN TEXAS PROVIDING LARGE SCALE
SUBSIDENCE WITH NOT MUCH IN THE WAY OF MOISTURE WITH PWATS AROUND
1.6 INCHES. THIS MEANS HOT AND DRY CONDITIONS WITH HIGHS OVER 100
DEGREES ACROSS MUCH OF DEEP SOUTH TEXAS WITH MID/UPPER 90S CLOSE
TO THE COAST. HEAT INDICES WILL RANGE FROM 106-110 DEGREES DURING
THE HEAT OF THE AFTERNOON HOURS POSSIBLY REACHING 112 DEGREES IN
ISOLATED SPOTS. DESPITE PERSISTENT HIGH PRESSURE...S/W TROUGH
ENTERING THE CA COAST FRIDAY AND RIDING OVER THE RIDGE WILL INDUCE
LEE TROUGHING THROUGH THE WEEKEND WHICH WILL RATCHET UP THE WINDS
IN OUR NECK OF THE WOODS INTO EARLY NEXT WEEK. REALLY...THE ONLY
CHANGE IN THE STREAK OF HOT AND DRY CONDITIONS MAY COME NEXT WEEK
AS HIGH PRESSURE RETREATS AS THE AFOREMENTIONED S/W TROUGH MOVES
ACROSS THE MIDWEST AND SUPPORTS A WEAK BOUNDARY INTO THE SE CONUS.
HIGHER MOISTURE ADVECTS IN UNDERNEATH THE RIDGE BEGINNING TUESDAY
IN THE FORM OF MORE CLOUDS AND MAYBE A CHANCE FOR SHOWERS.

&&

.MARINE...NOW THROUGH THURSDAY...DIURNAL THERMAL GRADIENT WINDS TO
CONTINUE EACH DAY AND EVENING TODAY THROUGH THURSDAY. WINDS TO
INCREASE AND REACH SCEC LEVELS OVER THE LAGUNA WHILE THE GULF WATERS
DIMINISH. AS WE MOVE INTO THE NIGHT THE WARMER 85 DEGREE WATER
TEMPERATURES TO PROMPT SUFFICIENT MIXING FOR MODERATE WINDS OVER THE
GULF WATER. SEAS WILL BE STEADY STATE RANGING BETWEEN 2 AND 4 FEET
WITH A SHORT FETCH AND LOW DURATION OF THE MODERATE WINDS.

THURSDAY NIGHT THROUGH SUNDAY...A MODERATE PRESSURE GRADIENT
DEVELOPS BETWEEN LOW PRESSURE OVER THE SOUTHERN PLAINS AND HIGH
PRESSURE OVER THE GULF OF MEXICO. MODERATE AND GUSTY WINDS DURING
THE AFTERNOON HOURS ON THE LAGUNA MAY WARRANT EXERCISE CAUTION
VALUES EACH AFTERNOON. ON THE GULF THE MODERATE WINDS TO DEVELOP
DURING THE OVERNIGHT PERIOD WITH SLIGHTLY WEAKER WINDS DURING THE
DAYTIME HOURS. SEAS TO REMAIN IN THE LOW TO MODERATE RANGE.

&&

.FIRE WEATHER...THE STRONGER WINDS, HEAT AND DRIER CONDITIONS
DEVELOPING DURING THE AFTERNOON ARE BEGINNING TO TAKE THEIR TOLL ON
THE GRADUALLY CURING FUELS OF TALL GRASSES. A RANGELAND FIRE
DISCUSSION IS WARRANTED FOR THE WESTERN AND NORTHERN RANCH LANDS AS
SOME FIRES HAVE BEEN BREAKING OUT AND SPREADING WITH THE BREEZY AND
DRIER CONDITIONS.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  95  80  95  82 /   0   0   0   0
BROWNSVILLE          95  80  96  80 /   0   0   0   0
HARLINGEN           100  79 101  78 /   0   0   0   0
MCALLEN             103  80 103  80 /   0   0   0   0
RIO GRANDE CITY     105  79 106  79 /   0   0   0   0
SOUTH PADRE ISLAND   90  81  90  82 /   0   0   0  10

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...HEAT ADVISORY FROM NOON TODAY TO 6 PM CDT THIS EVENING FOR
     TXZ251>257.

GM...NONE.
&&

$$

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

SHORT TERM...59
LONG TERM...55
GRAPHICS/UPPER-AIR...TORRES/HERGERT



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