AFDBRO AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BROWNSVILLE TX 1224 AM CDT MON JUN 27 2011 .DISCUSSION...SEE AVIATION SECTION BELOW FOR UPDATED DISCUSSION ON THE 06Z TAF PACKAGE. && .AVIATION...VFR CONDITIONS ARE EXPECTED TO PREVAIL THROUGH THE NEXT 24 HOURS OVER AREA TERMINALS. MOST SITES ARE SEEING RATHER CLEAR CONDITIONS EARLY THIS MORNING. THERE MAY BE SOME PERIODS OF MVFR CIGS DEVELOP DURING THE PREDAWN HOURS. HOWEVER...ANY OF THIS CLOUD COVER WILL SCATTER AND LIFT QUICKLY AFTER SUNRISE. PARTLY CLOUDY SKIES WILL AGAIN DEVELOP DURING THE DAYTIME HOURS...WHICH SHOULD BEGIN TO CLEAR IN THE EVENING. OTHERWISE...SOMEWHAT LIGHT WINDS WILL INCREASE OUT OF THE EAST TO SOUTHEAST AFTER SUNRISE AND BECOME A LITTLE GUSTY. WINDS WILL BEGIN TO LET UP BY THIS EVENING. && .PREV DISCUSSION... /ISSUED 615 PM CDT SUN JUN 26 2011/ DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW AVIATION...VFR CONDITIONS, MODERATE SOUTHEASTERLY WINDS AND PARTLY CLOUDY SKIES ARE BEING REPORTED AT THE REGIONAL AIRPORTS. THE WINDS WILL BECOME LIGHT AND VARIABLE OVERNIGHT TONIGHT. LIGHT TO MODERATE SOUTHEASTERLY WINDS WILL PREVAIL ACROSS THE CWA ON MONDAY WITH PARTLY CLOUDY SKIES. CLOUDINESS WILL INCREASE EARLY MONDAY MORNING ACROSS PORTIONS OF THE CWA REDUCING CEILINGS TO TEMPORARY MVFR CONDITIONS. VFR TO MVFR CONDITIONS WILL PREVAIL ACROSS THE REGIONAL AIRPORTS DURING THE NEXT 24 HOURS. PREV DISCUSSION... /ISSUED 214 PM CDT SUN JUN 26 2011/ SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...MID LEVEL RIDGING OVER TEXAS WILL SUPPORT SURFACE HIGH PRESSURE OVER THE NORTH GULF OF MEXICO TO PROVIDE DEEP ONSHORE FLOW ACROSS THE LOWER TEXAS COAST AND DEEP SOUTH TEXAS. EXCEPT FOR MORNING GULF SHOWERS MOVING ONSHORE... NOT EXPECTING MUCH IN THE WAY OF RAIN IN THE SHORT TERM. THE SEA BREEZE HAS NOT BEEN ESPECIALLY PRODUCTIVE RECENTLY...AND MOST SHOWER ACTIVITY HAS ORIGINATED ON THE GULF. OTHERWISE...MOSTLY CLEAR SKIES TONIGHT WILL GIVE WAY TO PARTLY OR MOSTLY CLOUDY SKIES WITH LOW CLOUDS MONDAY. A LOWER PWAT VALUE MONDAY SUGGESTS LESS CHANCE OF RAIN THAN TODAY...WHILE LIGHT TO MODERATE SOUTHEAST WINDS WILL BACK TO EAST AS SURFACE HIGH PRESSURE RETREATS SLIGHTLY TO THE NORTH AND EAST. A TROPICAL WAVE WILL LOWER PRESSURES IN THE SOUTHWEST GULF AS WELL...WITH INCREASED SHOWER AND THUNDERSTORM ACTIVITY THERE. TEMPS WILL BE NEAR SEASONAL NORMS...WITH LOWER TEMP TRENDS OVER THE UPPER VALLEY HOLDING HEAT INDEX VALUES A BIT LOWER. LONG TERM /TUESDAY THROUGH SUNDAY/...THE LONG RANGE OUTLOOK FOR DEEP SOUTH TX WILL BE HIGHLY DEPENDENT ON THE OVERALL TRACK AND LEVEL OF DEVELOPMENT OF THE W-NW MOVING TROPICAL WAVE NOW LOCATED OVER THE YUCATAN PENINSULA. BOTH THE ECMWF AND THE GFS KEEP THIS FEATURE MOVING ON A GENERAL W-NW DIRECTION WITH THE ECMWF BRINGING THE FEATURE INLAND OVER THE MEXICAN COASTLINE BETWEEN TAMPICO AND VERA CRUZ AS A SURFACE LOW. THE GFS SEEMS TO SLOW DOWN THIS FEATURE AND MAINTAINS A BROAD SURFACE LOW MEANDERING AROUND THE SW GULF OF MEX THROUGH NEXT WEEKEND. SINCE THE BROAD MID LEVEL RIDGE WILL REMAIN DOMINANT OVER THE SOUTH CENTRAL STATES...NORTHERN MEX AND THE NORTHERN GULF OF MEX BELIEVE THAT THE GFS SOLUTION DOES NOT LOOK REASONABLE AND FAVOR THE ECMWF. ALSO THE UKMET AGREES BETTER WITH THE ECMWF SURFACE SOLUTION IN THE PLACEMENT OF THIS TROPICAL WAVE. THE LATEST TROPICAL OUTLOOK FROM NHC PLACES A LOW CHC OF THIS FEATURE BECOMING A TROPICAL CYCLONE OVER THE NEXT 48 HOURS SO AT THIS TIME THE MAIN THREAT FROM THIS FEATURE FOR DEEP SOUTH TX WILL LIKELY BE THE INCREASING CONV POTENTIAL LATER THIS UPCOMING WEEK. THE RUN TO RUN CONSISTENCY WITH GFS MEX POPS HAVE BECOME MORE ERRATIC SINCE YESTERDAY WITH THE LATEST RUN SHOWING A MUCH WETTER SOLUTION FOR DEEP SOUTH TX ON AND AFTER WED. HAVE DISREGARDED THE GFS AND WILL GO WITH THE MORE CONSERVATIVE POPS FROM THE ECMWF WHICH MAINTAINS SLIGHT CHC/CHC POPS FOR THE REGION IN THE 3 TO 7 DAY RANGE. WILL BE GOING ABOVE MEX TEMP GUIDANCE AS THE CURRENT MODEL TEMPS APPEAR TOO LOW CONSIDERING THE WETTER SOLUTION GENERATED BY THE 12Z GFS RUN. AS ALWAYS PLEASE REFER TO THE LATEST TROPICAL WEATHER OUTLOOK FROM NHC CONCERNING THE PROGRESS OF THE YUCATAN TROPICAL WAVE. MARINE...TONIGHT THROUGH MONDAY NIGHT...BUOY 20 REPORTS LIGHT SSE WINDS AND MODERATE SEAS BETWEEN 3 AND 4 FEET EARLY THIS AFTERNOON. UNSETTLED CONDITIONS WILL CONTINUE OFFSHORE WITH TROPICAL MOISTURE FUELING ISOLATED SHOWERS THROUGH THE SHORT TERM. ANTICYCLONIC FLOW WILL RESULT IN MODERATE SOUTHEAST WINDS AND MODERATE SEAS. ONLY BRIEF EXERCISE CAUTION PERIODS MAY OCCUR OFFSHORE DUE TO SLIGHTLY STRONGER ONSHORE WINDS. IN THE LONGER RANGE MARINE PERIOD THE LATEST WAVE NUMERICAL GUIDANCE IS GOING VERY AGGRESSIVE WITH BUILDING LARGER SWELLS OFFSHORE. THIS IS APPARENTLY DUE TO POSITIVE FEEDBACK FROM THE LONGER RANGE GUIDANCE CONCERNING THE POTENTIAL FOR TROPICAL DEVELOPMENT IN THE SW GULF. BELIEVE THAT THE NUMERICAL GUIDANCE IS OVERDONE WITH THE SWELL DEVELOPMENT AND WILL GO UNDER THIS IN THE LONGER RANGE PERIODS KEEPING CONDITIONS BELOW SCA LEVELS. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 89 79 91 79 / 20 10 10 10 BROWNSVILLE 92 79 93 79 / 20 10 10 10 HARLINGEN 91 77 96 78 / 20 10 10 10 MCALLEN 94 77 98 77 / 20 10 10 10 RIO GRANDE CITY 94 77 101 77 / 10 10 10 10 SOUTH PADRE ISLAND 86 80 86 80 / 10 10 10 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$