000
FXUS64 KBRO 202345 AAA
AFDBRO

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BROWNSVILLE TX
645 PM CDT SUN JUL 20 2014

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

&&

.AVIATION...MVFR CONDITIONS ARE ANTICIPATED TO DEVELOP LATER
TONIGHT AS CLOUDS DEVELOP AT OR BELOW A STRONG LOW LEVEL
INVERSION. VFR CONDITIONS EXPECTED THROUGH 05Z BEFORE THE INCREASE
IN STRATUS BEGINS. BKN CONDITIONS DEVELOP THROUGH THE OVERNIGHT
HOURS WITH SOME PATCHY FOG OR HAZE AROUND SUNRISE WITH CONDITIONS
BECOME MOST SATURATED. MEDIUM CONFIDENCE IN THE LOWER CEILING CONDITIONS
WITH THE HIGHER RESOLUTION MODELS SUGGESTING 80 PERCENT BETTER BUT
A MUCH LOWER CHANCE OF MVFR VSBY. AS DAYTIME HEATING COMMENCES
MONDAY LOWER CLOUDS TO BREAK UP WITH VFR CONDITIONS THROUGH THE
DAY. LIGHT SOUTHEAST WINDS TONIGHT TO INCREASE SLIGHTLY MONDAY
WITH GUSTS BETWEEN 20-23 KNOTS.

&&

.PREV DISCUSSION... /ISSUED 320 PM CDT SUN JUL 20 2014/

SHORT TERM /NOW THROUGH MONDAY NIGHT/...MUCH MORE STABLE ATMOSPHERE
IN THE VICINITY THIS AFTERNOON AS RIDGING MOVES INTO TEXAS FROM THE
WEST. VISIBLE SATELLITE IMAGERY SHOWS THAT CU FIELD HAS DISSIPATED
ACROSS THE LOWER VALLEY...AN INDICATOR THAT DRIER AIR IS FILTERING
IN FROM THE SOUTH. THIS IS ALSO NOTED IN GOES PW IMAGERY. MODEL
CONSENSUS SHOWS PW VALUES FALL TO AROUND 1.5 INCHES BY TONIGHT AND
REMAIN THROUGH TOMORROW NIGHT. THIS SHOULD PROHIBIT THE FORMATION OF
SHOWER ACTIVITY IN THE SHORT TERM. MODEL DATA SHOWS THAT THE
REMAINING MOISTURE WILL REMAIN TRAPPED BELOW THE CAPPING
INVERSION...CURRENTLY 2500 TO 3000 FEET. THIS WILL KEEP SOME
OVERNIGHT CLOUD COVER FOR THE REGION...BUT WILL QUICKLY BURN OFF BY
MIDMORNING MONDAY. WITH GENERALLY IN THE 70S THE ENTIRE SHORT TERM
PERIOD...HEAT INDEX VALUES WILL REMAIN ABOVE 90 DEGREES OVERNIGHT
AND 105 TO 110 DURING THE AFTERNOON PEAK HEATING.

LONG TERM...TUESDAY THROUGH SUNDAY...STRONG 500 MB RIDGING WILL
INITIALLY REMAIN ENTRENCHED OVER THE AREA WITH FAIRLY LIMITED
DEEPER LAYER MOISTURE VALUES EXPECTED THROUGHOUT THE UPCOMING WORK
WEEK. THIS WILL LIKELY MAINTAIN TEMPS CLOSE TO PERSISTENCE THROUGH
DAY 7. BOTH THE GFS AND ECMWF GENERALLY AGREE ON THE POSITION OF
THE 500 MB RIDGE. HOWEVER...THE ONE BIG DIFFERENCE BETWEEN THE TWO
MODELS IS THE WESTWARD PROGRESSION 500 MB TROFFING FROM THE
EASTERN STATES INTO THE MEAN RIDGE POSITION OVER THE S0UTH CENTRAL
PLAINS STATES. IF THE ECMWF VERIFIES...ENOUGH MID LEVEL TROFFING
MAY OCCUR TO ALLOW A LITTLE MORE ACTIVE SEA BREEZE OR DIURNALLY
DRIVEN CONV. AS MENTIONED EARLIER THE BIG LIMITATION FOR CONV WILL
BE THE ABSENCE OF SERIOUS DEEPER LAYER MOISTURE. SO FOR NOW WILL
MENTION ONLY SILENT 10 POPS THROUGH SUNDAY AND WILL SEE IF FUTURE
RUNS OF THE GFS AND ECMWF TRY TO GEL CLOSER TO A MORE COMMON
SOLUTION.

FOR TEMPS WILL LEAN CLOSER TO THE WARMER ECMWF NUMBERS AS THE GFS
MEX MOS NUMBERS APPEAR TO BE UNDERDOING THE MAX TEMPS ESPECIALLY
OUT WEST FOR THE REST OF THIS UPCOMING WEEK. FOR MINS WILL GO
CLOSE TO A MODEL BLEND THROUGH DAY 7.

NHC IS MONITORING A BROAD AREA OF LOW PRESSURE OVER THE EASTERN
ATLANTIC. THEIR EXPECTATIONS FOR DEVELOPMENT OF THIS FEATURE ARE
PRETTY LOW AT THIS TIME AS IT MOVES WEST. BOTH THE GFS AND ECMWF
SHOW NO REAL DEVELOPMENT OF THE WAVE AND EVENTUALLY DISSIPATE THE
FEATURE TOWARDS THE END OF THE WEEK.

MARINE...NOW THROUGH MONDAY NIGHT...MARINE CONDITIONS REMAIN
REASONABLE FOR FOR THE NEXT 36 HOURS WITH WEAK SOUTHEAST FLOW
CONTINUING. WINDS WILL RELAX TO 10 TO 15 KNOTS OVERNIGHT...MAINLY
FOR THE OFFSHORE GULF WATERS. WINDS REMAIN STEADY FOR THE GULF
WATERS TOMORROW...WITH SOME HIGHER BREEZES ACROSS THE LAGUNA MADRE.
SEAS REMAIN LONG-FETCH DOMINATED...SWELLING TO 3 TO 4 FEET THROUGH
MONDAY NIGHT.

TUESDAY THROUGH FRIDAY...BROAD SURFACE RIDGING REMAINS IN CONTROL
OF THE MARINE CONDITIONS OVER THE GULF OF MEX AND THE WESTERN
ATLANTIC THROUGHOUT THE UPCOMING WEEK. THIS WILL MAINTAIN LIGHT TO
MODERATE S-SE WINDS AND FAIRLY LOW SEAS IN PLACE THROUGH FRIDAY.
NO SCA CONDITIONS EXPECTED AT THIS TIME FOR EITHER THE BAY OR
GULF WATERS.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  81  94  82  95 /   0   0   0  10
BROWNSVILLE          79  96  80  96 /   0   0   0  10
HARLINGEN            78  98  79  98 /   0   0   0  10
MCALLEN              79 100  80 100 /   0   0   0   0
RIO GRANDE CITY      79 100  79 102 /   0   0   0   0
SOUTH PADRE ISLAND   79  90  81  89 /   0   0   0  10

&&

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

$$

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

59/68