AFDBRO AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BROWNSVILLE TX 334 AM CDT FRI JUL 8 2011 .SHORT TERM /TODAY THROUGH SATURDAY/...IR SATELLITE IMAGERY SHOWS A RELATIVELY CLEAR PICTURE FOR THE WEST GULF OF MEXICO AND THE SOUTH AND WEST PORTIONS OF TEXAS. H5 RIDGING UPSTREAM AND SURFACE HIGH PRESSURE OVER THE WEST GULF WILL PERSIST IN THE SHORT TERM. AN ELONGATED AREA OF LOW PRESSURE FROM THE YUCATAN PENINSULA TO THE WEST COAST OF FLORIDA IS NOT EXPECTED TO PLAY A ROLE ON THE WESTERN SIDE OF THE GULF. USED A MET/MAV BLEND TO NUDGE HIGH TEMPS A DEGREE OR SO ABOVE PURE MAV GUIDANCE...WHICH WILL ESSENTIALLY BE A DEGREE ABOVE YESTERDAY...WHICH SEEMED REASONABLE GIVEN THE FORECAST OF AMPLE SUNSHINE AND LOWERING GROUND MOISTURE. OTHERWISE...SHOULD SEE A FEW MORNING LOW CLOUDS...FOLLOWED BY FEW TO SCT LOW CU AND A WEAK IF ANY SEA BREEZE GIVEN THE RELATIVELY LOW PWAT...LESS THAN 1.5 INCHES BEING FORECAST FOR TODAY. MOISTURE WILL BE SLIGHTLY HIGHER ON SATURDAY IN PART DUE TO A WEAK FRONTAL BOUNDARY MOVING INTO THE NORTHWEST GULF...PROVIDING A SOURCE OF MOISTURE TO BE PICKED UP BY ONSHORE WINDS. HEAT INDEX VALUES ON SATURDAY WILL CREEP ABOVE THE CENTURY MARK TO NEAR 105 AT SOME PLACES NEAR THE RIVER AND INLAND. LIGHT TO MODERATE SOUTH SOUTHEAST WINDS WILL PREVAIL. .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...A WEAK MID-LEVEL LOW PRESSURE SYSTEM WILL GRADUALLY RETROGRADE FROM THE LOWER TEXAS COAST AT THE BEGINNING OF THE PERIOD...TO THE TEXAS BIG BEND AND FINALLY THE TEXAS PANHANDLE BY TUESDAY NIGHT. THE PASSAGE OF THIS SYSTEM... COMBINED WITH DEEPER TROPICAL MOISTURE...FEATURING PRECIPITABLE WATER VALUES BETWEEN 1.5 AND 2.0 INCHES...WILL PRODUCE ISOLATED SHOWERS AND THUNDERSTORMS DURING THE DAYLIGHT HOURS LATER IN THE WEEKEND INTO EARLY NEXT WEEK...WITH STREAMER SHOWERS DURING THE OVERNIGHT HOURS OF THE SAME PERIOD. MID-LEVEL HIGH PRESSURE THEN BUILDING SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY...AND THEN WEST INTO THE LONE STAR STATE...WILL EFFECTIVELY ENFORCE DRIER WEATHER WITHIN THE RIO GRANDE VALLEY FOR WEDNESDAY AND THURSDAY. HOWEVER...ENOUGH DEEP TROPICAL MOISTURE WILL LINGER TO ALLOW FOR CONTINUED STREAMER ACTIVITY AT NIGHT DURING THIS TIME. WELL ABOVE NORMAL TEMPERATURES AT THE START OF THE LONG TERM FORECAST PERIOD WILL GRADUALLY WARM AS THE INITIAL PRECIPITATION CHANCES WANE AND GIVE WAY TO THE MORE OPPRESSIVE MID-LEVEL HIGH PRESSURE SYSTEM... RESULTING IN DOWNRIGHT HOT CONDITIONS BY THE END OF THE FORECAST. && .MARINE...TODAY THROUGH SATURDAY...THE LATEST OB FROM BUOY020 SHOWED LIGHT SSE WINDS AND SEAS OF ONE TO TWO FT WITH A PERIOD OF 3 SECONDS. THAT`S THE WAY IT WILL GO IN THE SHORT TERM WITH BROAD HIGH PRESSURE ACROSS THE WESTERN GULF OF MEXICO. LIGHT TO MODERATE SOUTHEAST WINDS AND LOW TO MODERATE SEAS OF ONE TO THREE FEET WILL BE THE PRIMARY FORECAST. HOWEVER...PRESSURE FALLS OVER THE SOUTHERN HIGH PLAINS FRIDAY NIGHT INTO SATURDAY WILL TIGHTEN THE GRADIENT SLIGHTLY... RESULTING IN 15 TO 20 KNOT SOUTH SOUTHEAST WINDS AND EXERCISE CAUTION CONDITIONS ON THE GULF LATE FRIDAY...BUT WITH MODERATE WINDS ON SATURDAY. SATURDAY NIGHT THROUGH THURSDAY...SURFACE HIGH PRESSURE OVER THE GULF OF MEXICO WILL INTERACT MODERATELY WITH LOW PRESSURE THAT WILL PERSIST OVER THE TEXAS BIG BEND AND EXTREME WEST TEXAS. THIS PATTERN WILL PRODUCE LIGHT TO MODERATE WINDS AND LOW TO MODERATE SEAS FOR THE ADJACENT COASTAL WATERS OF DEEP SOUTH TEXAS THROUGH THE PERIOD. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 92 79 92 79 / 10 10 10 10 BROWNSVILLE 93 77 93 77 / 10 0 10 10 HARLINGEN 95 75 95 77 / 10 0 10 10 MCALLEN 97 77 97 77 / 10 0 10 0 RIO GRANDE CITY 99 76 100 77 / 0 0 0 0 SOUTH PADRE ISLAND 89 80 89 79 / 10 10 10 10 && .BRO WATCHES/WARNINGS/ADVISORIES...NONE. && $$