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000 FXUS62 KMFL 211745 AFDMFL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 145 PM EDT SUN SEP 21 2008 .AVIATION...VFR CONDITIONS WILL PREVAIL NEXT 24 HOURS ACROSS ALL OF S FLA. SEA BREEZE CIRCULATION WELL UNDERWAY ALONG THE E CST SO ALL SHRA HAVE DEVELOPED FAR TO THE WEST OF THE E TERMINALS AND THIS WILL BE THE TREND FOR THE REMAINDER OF THE AFTERNOON HOURS. A FEW TSRA MAY DEVELOP INTERIOR AND THEN MOVE INVOF KAPF AND HAVE PLACE THIS IN THEIR TAF BTWN 20Z AND 00Z. IN ADDITION, W CST SEA BREEZE WILL SET UP AROUND 19Z ALTHOUGH SOME MODEL GUIDANCE SUGGESTS UP TO AN HOUR EARLIER BUT WENT WITH PERSISTENCE AS FLOW PATTERN SIMILAR TO YESTERDAY. LIGHT E FLOW WILL RETURN AFT 00Z TO 02Z AT ALL SITES WITH VCSH SETTING UP ONCE AGAIN ALONG THE E CST. 30/KOB && .PREV DISCUSSION... /ISSUED 1104 AM EDT SUN SEP 21 2008/ UPDATE... NO MAJOR CHANGES WILL BE MADE TO THE FIRST PERIOD FORECAST THIS MORNING...WITH EVERYTHING APPEARING TO BE IN GOOD SHAPE AT THIS TIME. LATEST IMAGERY FROM KAMX INDICATES A DISSIPATING TREND IN SHOWER ACTIVITY OVER THE ATLANTIC AND OFF SHORE GULF WATERS. HOWEVER...EXPECT REGENERATION OF AT LEAST WIDELY SCATTERED SHOWERS/THUNDERSTORMS OVER THE MAINLAND EARLY THIS AFTERNOON...AS LOW-LEVEL DESTABILIZATION OCCURS. THIS IS ALREADY REFLECTED IN THE CURRENT FORECAST...WITH NO CHANGES REQUIRED. 70/DD AVIATION DISCUSSION... /ISSUED 749 AM EDT SUN SEP 21 2008/ AVIATION...MOSTLY VFR CONDITIONS WILL PREVAIL IN LIGHT EASTERLY FLOW. ISOLD SHRA WILL MOVE ONSHORE OF THE SE CST THIS MORNING WITH AND HAVE PLACED VCSH IN ALL E CST TERMINALS WITH THE EXCEPTION OF KPBI. ONE SUCH SHRA WILL MOVE OVER KPBI THROUGH 13Z AND HAVE ACCOUNTED FOR THIS BY INCLUDING A TEMPO GROUP FOR THE FIRST HOUR. IN THIS FLOW, MOST CONVECTION SHOULD BE EAST OF THE TERMINALS BY 18Z WITH THE POSSIBILITY OF ISOLD TSRA GETTING CLOSE TO KAPF AFT 19Z AS THE W CST SEA BREEZE SETS UP. WIND FLOW WILL BECOME DIMINISH AGAIN AFT 02Z. 30/KOB PREV DISCUSSION... /ISSUED 349 AM EDT SUN SEP 21 2008/ DISCUSSION...A WEAK UPPER LOW OFF OF THE E FLA COAST DISSIPATES TODAY AND ALLOWS THE MID ATLC RIDGE TO THE SE TO REBUILD SLIGHTLY OVER THE AREA TODAY AND TONIGHT. MON...AS A STRONG LONG WAVE UPPER RIDGE OVER THE GREAT PLAINS MOVES EASTWARD...AN UPPER TROUGH BEGINS TO DEVELOP OVER NEW ENGLAND THAT EXTENDS SW INTO THE TN RIVER VALLEY. BY TUE...THIS TROUGH DEEPENS...SHOVES THE ATLC RIDGE SE ...WITH A CUTOFF UPPER LOW DEVELOPING OVER THE SE U.S./N AND CENTRAL FLA PENINSULA WHICH WILL PERSIST INTO NEXT WEEKEND. FOR THE SHORT TERM...TODAY THROUGH TUE...SOME DRY SUBSIDENT AIR ALOFT REMAINS OVER S FLA TODAY AGAIN CURTAILING THE CHANCES OF RAIN. LOW POPS E WHICH GRADUALLY RISE TO THE W BUT REMAIN BELOW NORMS. LIMITED E COAST POPS TONIGHT WHICH END IN THE EVE W. MON THE ATMO -SPHERE BEGINS TO DESTABILIZE AND MOISTURE GRADUALLY BEGINS TO INCREASE WITH A SLIGHTLY DEEPER EASTERLY FLOW WITH THE TREND CONTINUING INTO TUE. EXTENDED PERIOD...WED THROUGH SAT...ATMOSPHERE CONTINUES TO SLOWLY DESTABILIZE AND MOISTEN AS UPPER LOW DEVELOPS OVER THE SE U.S. POSSIBLE DIVERGENT FLOW ALOFT A FACTOR AND WEATHER BEGINS TO TREND FROM W TO E IN A REVERSAL OF THE NORMAL S FLA LATE SUMMER/EARLY FALL PATTERN. THE A LARGE TROUGH OVER E U.S. THE GLOB OF WEATHER S OF PUERTO RICO IN THE CARIBBEAN SHOULD PULL NORTHWARD AND REMAIN WELL E OF S FLA. THE UPPER LOW WILL GENERATE A SURFACE LOW OFF OF THE NC COAST WHICH MAY PULL A FRONT?...AT LEAST POSSIBLY COOLER AND DRIER AIR OVER S FLA NEXT WEEKEND. ONE CAN HOPE. MARINE...EASTERLY WINDS LESS THAN 15 KNOTS WITH GULF STREAM SEAS UP TO 4 FEET AT TIMES WHEN WINDS DEVELOP A NE TREND TODAY THROUGH TUE. BY WED AND THU...LOW PRES DEVELOPING OVER THE THE ATLC OFF OF THE SE U.S. COAST MAY BEGIN TO GENERATE SOME SWELLS THAT MAY IMPACT MAINLY THE PALM BEACH WATERS WITH SEAS TO 7 FEET. A SMALL SWELL STILL AFFECTING PALM BEACH WATERS TODAY. FIRE WEATHER...NO FIRE WEATHER CONCERNS THROUGHOUT THE FORECAST PERIOD AS MINIMUM RH VALUES REMAIN SUFFICIENTLY HIGH. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 77 88 76 88 / 20 30 30 40 FORT LAUDERDALE 80 89 78 87 / 20 30 30 40 MIAMI 78 89 77 88 / 20 30 30 40 NAPLES 75 91 74 90 / 20 30 30 50 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$