518 FXUS64 KBRO 240054 AAA AFDBRO AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BROWNSVILLE TX 754 PM CDT FRI MAY 23 2014 .DISCUSSION...UPDATED FOR LATEST AVIATION DISCUSSION BELOW. && .AVIATION...VSBL AND IR SATL IMAGERY OVER THE REGION SHOWS PLENTY OF MID AND HIGH LEVEL CLD COVER ADVECTING OVER THE REGION FROM THE CONV FIRING OVER THE HIGHER MOUNTAINS IN CENTRAL AND NORTHEASTERN MEXICO. A FAIRLY MOIST ATMS IS IN PLACE OVER DEEP SOUTH TX AHEAD OF THE LARGE 500MB CLOSED LOW OVER THE DESERT SW. EXPECT SOME LOWER LEVEL SC TO DEVELOP LATER TONIGHT AND SHOULD PERSIST THROUGH SUNRISE TOMORROW. THE SURFACE GRADIENT FLOW WILL INCREASE AFTER SUNRISE TOMORROW ALLOWING THE LOWER LEVEL CLD DECKS TO MIX OUT ALLOWING A RETURN OF MVFR/VFR CEILINGS. ANY CONV THAT FORMS LATER TONIGHT INTO TOMORROW WILL LIKELY STAY WEST OF THE LOWER RGV AIRPORTS SO WILL LEAVE OUT ANY MENTION OF CONV IN THE TAFS AT THIS TIME. && .PREV DISCUSSION... /ISSUED 203 PM CDT FRI MAY 23 2014/ SHORT TERM /NOW THROUGH SATURDAY NIGHT/...AN AREA OF LOW PRESSURE LOCATED OVER EASTERN CA AND WESTERN ARIZONA BEGINS TO MIGRATE INTO THE FOUR CORNERS REGION THROUGH THE SHORT TERM PERIOD. THE DIRECTIONAL MOVEMENT OF THIS LOW WILL DICTATE WHAT LOCATIONS WILL GET THE HEAVIEST RAIN OR NO RAIN AT ALL. AS THE UPPER LEVEL LOW SLOWLY MIGRATES EASTWARD A STRONGLY DIFFLUENT SUBTROPICAL JET MAX UNDER THE UPPER TROUGH MOVES EASTWARD INTO THE CWA. THIS FEATURE ORIGINATES AS A TROPICAL MOISTURE PLUME OFF THE INTERTROPICAL CONVERGENCE ZONE AND APPEARS TO BE AT LEAST PARTIALLY ENHANCED BY OUTFLOW FROM TROPICAL STORM AMANDA. PWATS VALUES WILL CONTINUE TO INCREASE AS THE UPPER LOW MOVES EAST BUT MAINLY FAVORS THE WESTERN PORTION OF THE CWA. WINDS AT THE SURFACE REMAIN STEADY OUT OF THE SOUTHEAST. THIS WILL CONTINUE TO FAVOR GULF MOISTURE TO SURGE INTO THE AREA. DEW POINTS WILL REMAIN HIGH WITH TEMPERATURES STEADY IN THE MID TO LOW 90S ACROSS THE FORECAST AREA AND INTO THE 80S ALONG THE COAST. THE GFS/NAM/ECMWF CONTINUE WITH GOOD AGREEMENT WITH THE MOVEMENT OF THIS LOW AND ITS LOCATION. KEPT MOST OF THE POPS FOR THE WESTERN PORTION OF THE CWA AS THE RH VALUES ARE MORE FAVORABLE TO DEVELOP SHOWERS OVER THE SIERRA MADRE AND GRADUALLY PROGRESS INTO THE WESTERN PORTION OF THE AREA. THE FURTHER EAST INTO THE COASTAL AREAS...THE LESS POTENTIAL THERE IS DUE TO THE LACK OF DEEPER MOISTURE AND UPPER LEVEL SUPPORT. TONIGHT...SOUTHEAST WINDS WILL DIMINISH AND REMAIN LIGHT OVERNIGHT WITH MOSTLY CLOUDY CONDITIONS KEEPING TEMPERATURES IN THE MID TO LOW 70S ACROSS THE AREA. IT APPEARS THE UPPER LEVEL ENVIRONMENT WILL SLOWLY BECOME MORE NEUTRAL TO HOSTILE THROUGH THE EVENING THOUGH AND KEPT THE TREND OF LOWERING POPS THROUGH THE NIGHT. SATURDAY AND SATURDAY NIGHT...THE CORE OF THE AFOREMENTIONED SUBTROPICAL JET MAX WILL SET UP BASICALLY OVERHEAD FOR SATURDAY AND THIS LOOKS TO LIMIT LOW LEVEL CONVERGENCE AND ANY REAL FOCUSING MECHANISM FOR THUNDERSTORMS. SOUTHWESTERLY 700MB WINDS INCREASE SOMEWHAT OVERNIGHT AND APPEAR TO PROVIDE SOME MID LEVEL DRYING SATURDAY AND SATURDAY NIGHT AS WELL LIMITING SHOWERS DEVELOPMENT. PARED BACK THE SLIGHT CHANCE POPS TO ALL BUT THE FAR WESTERN AREAS. TEMPERATURES LOOK TO BE A DEGREE OR TWO WARMER THAN SATURDAY WITH SLIGHTLY LESS CLOUD COVER. LONG TERM /SUNDAY THROUGH FRIDAY/...500MB LOW ACROSS THE SOUTHWEST UNITED STATES SUNDAY WILL MAKE ITS WAY INTO THE SOUTHERN PLAINS MONDAY INTO TUESDAY. MOISTURE FROM TROPICAL STORM AMANDA ACROSS THE EASTERN PACIFIC WILL MAKE ITS WAY NORTHWARD ACROSS MEXICO INTO TEXAS AHEAD OF THIS FEATURE. THIS WILL PROVIDE A SLIGHT CHANCE TO CHANCE OF SHOWERS AND THUNDERSTORMS ACROSS SOUTH TEXAS THROUGH THE REST OF THE WEEKEND INTO EARLY NEXT WEEK. BY THE MIDDLE OF NEXT WEEK...THE UPPER LEVEL LOW ACROSS EASTERN OKLAHOMA AND NORTHEAST TEXAS WEDNESDAY IS EXPECTED TO DRIFT SOUTHEAST AND WEAKEN THURSDAY INTO FRIDAY. WHILE THE SOUTHWEST FLOW ALOFT WILL VEER TO THE NORTHWEST TUESDAY INTO WEDNESDAY...WILL CONTINUE TO MENTION A SLIGHT CHANCE OF RAIN THROUGH THE REST OF THE WEEK AS THE LOW PROVIDES ENOUGH WEAKNESS IN THE 500MB RIDGE ACROSS DEEP SOUTH TEXAS FOR AT LEAST ISOLATED SEABREEZE CONVECTION TO DEVELOP IN THE AFTERNOON HOURS. MARINE... NOW THROUGH SATURDAY NIGHT...HIGH PRESSURE REMAINS OVER THE GULF WATERS KEEPING SOUTHEAST WINDS OVER THE AREA THROUGH THE SHORT TERM PERIOD. THE THERMAL LOW OVER THE SIERRA MADRE WILL INTERACT AND STRENGTHEN WITH THIS HIGH PRESSURE OVER THE GULF SATURDAY AFTERNOON. SCEC CONDITIONS WILL BE POSSIBLE AGAIN OVER THE LAGUNA MADRE TOMORROW. THIS WILL DECOUPLE OVER NIGHT OVER THE GULF AND LAGUNA MADRE WITH NO MUCH RAIN EXPECTED SATURDAY AND SATURDAY NIGHT. SUNDAY THROUGH WEDNESDAY...MODERATE SOUTHEAST WINDS WILL PREVAIL ACROSS THE COASTAL WATERS SUNDAY AND MONDAY WITH LOW PRESSURE ACROSS WEST TEXAS AND HIGH PRESSURE ACROSS THE GULF OF MEXICO. THE PRESSURE GRADIENT IS EXPECTED TO WEAKEN TUESDAY AND LIGHT TO MODERATE SOUTHEAST WINDS TUESDAY ARE PROGGED TO VEER TO THE SOUTH ON WEDNESDAY WITH A BROAD AREA OF LOW PRESSURE ACROSS SOUTHWEST TEXAS. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 76 85 75 85 / 10 10 10 10 BROWNSVILLE 74 85 75 86 / 10 10 10 20 HARLINGEN 74 89 74 89 / 10 10 10 20 MCALLEN 75 92 75 92 / 10 10 10 20 RIO GRANDE CITY 75 94 74 93 / 10 20 20 20 SOUTH PADRE ISLAND 75 81 74 81 / 10 10 10 10 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...NONE. && $$ THIS PRODUCT IS ALSO AVAILABLE ON THE WEB AT: HTTP://WEATHER.GOV/RGV SHORT TERM...60 LONG TERM...53