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Morning AFD Excerpts from around the Gulf Coast Region. NWS Jackson, MS ...BY SUNDAY...THE REMAINS OF THE FRONTAL ZONE SAG INTO SRN MS WHERE THEY STALL OUT FOR THE REST OF THE HOLIDAY WEEKEND AS A 590DM 500MB ANTICYCLONE BECOMES POSITIONED ALONG THE AL/TN BORDER. BY THIS TIME...HURC GUSTAV WILL LIKELY BE CRANKING THROUGH THE SRN/ERN/CENTRAL GULF REGION DEPENDING ON WHICH MODEL YOU CHOOSE. THE 00Z HWRF NOW ADVERTISING SUB 900MB PRESSURES FOR THIS STORM SO ALL INTERESTS AROUND THE GULF SHOULD KEEP TUNED TO LATER FORECASTS...ESPECIALLY CONSIDERING THE LABOR DAY HOLIDAY. Bold Emphasis added~danielw OBVIOUSLY OUR FORECAST WILL BE HIGHLY DEPENDENT ON THE FUTURE OF HURC GUSTAV WHICH UNFORTUNATELY WILL BE ENCOUNTERING EVEN WEAKER STEERING CURRENTS ACROSS THE GULF. BY MONDAY/TUESDAY...THE GFS SHOWS AN UPPER TROUGH IS PROGGED TO BE IN THE NERN GULF MOVING ESE. THIS 2-300MB TROUGH COULD VERY WELL SERVE TO SLOW/TURN OR EVEN LOOP GUSTAV BEFORE IT CAN PROGRESS TOO FAR WEST...WE`LL BE IN WAIT AND SEE MODE ON THIS ONE. NWS Slidell, La ...LATEST OFFICIAL NHC TRACK AND INTENSITY FORECAST FOR TROPICAL STORM GUSTAV PLACES THE STORM IN THE MIDDLE GULF PRECARIOUSLY SOUTH OF THE CENTRAL LOUISIANA COAST BY MONDAY MORNING. HAVE INTRODUCED DETERIORATING CONDITIONS FOR ALL OF THE FORECAST OFFICE WITH THE IMPLICATION OF LOWER DAYTIME TEMPERATURES...70-80 PERCENT POPS AND RA+ WEATHER ELEMENT BASED ON TRACK EXTRAPOLATION...THOUGH THE MAIN MESSAGE WILL BE HIGH UNCERTAINTY THAT FAR OUT. THE PROBLEM IS THE REQUIREMENT OF A DETERMINISTIC FORECAST FOR TUESDAY WITH A PROBABLISTIC UNCERTAINTY OF TROPICAL CYCLONE FORECASTING. OF COURSE...CHANGES WILL BE FORTHCOMING AS FORECAST TRACK BECOMES MORE CERTAIN IN TIME. NWS Tallahassee,Fl .LONG TERM (SATURDAY-WEDNESDAY)...THE MAIN PLAYER FOR THE SENSIBLE WEATHER EARLY IN THE PERIOD WILL BE THE MID/UPPER LEVEL ANTICYCLONE FROM THE FL STRAITS INTO THE SERN CONUS, AND A DEVELOPING MID/UPPER LEVEL TROUGH OVER THE NWRN GOMEX. THESE SYSTEMS SHOULD STEER HURRICANE GUSTAV ON A NWLY COURSE INTO THE CENTRAL GOMEX BY THE END OF THE WEEKEND PER THE LATEST NHC FCST TRACK. OUTLIERS ARE THE GFDL AND ECMWF WHICH ACCELERATE THE TROPICAL CYCLONE NWWD TOWARD THE TX COAST. THE 00Z GFS TAKES GUSTAV FURTHER N ACROSS THE FL STRAITS LATE SATURDAY AND EVENTUALLY MEANDERS THE SYSTEM OVER THE ERN GOMEX. DUE TO THE MODEL DIFFERENCES IN THE TRACK OF GUSTAV, LOW CONFIDENCE DICTATES NEAR CLIMO POPS FOR MAINLY DIURNAL SHWRS/TSTMS. BASED ON THE PROJECTED POSITION OF GUSTAV BY 120 HRS, WILL CONSIDER RAISING WINDS AND SEAS (MAINLY SWELL) FOR OUR OFFSHORE LEGS BEGINNING ON SUNDAY. ALL INTERESTS ALONG THE GULF COAST WILL NEED TO CLOSELY MONITOR THE PROGRESS OF GUSTAV. NWS Tampa,Fl .LONG TERM (FRIDAY NIGHT-TUESDAY)...SIMILAR TO YESTERDAY A LOT OF UNCERTAINTY EXISTS WITH RESPECT TO THE EVOLUTION AND EVENTUAL TRACK OF TROPICAL CYCLONE GUSTAV DURING THE LONG TERM PERIOD. GLOBAL MODELS THIS MORNING ARE OFFERING VARIOUS SOLUTIONS...SO CONFIDENCE IN ANY ONE REMAINS RATHER LOW AT THIS TIME. GIVEN THIS WILL MAKE LITTLE CHANGES TO INHERITED GRIDS AND WILL KEEP RAIN CHANCES AND TEMPERATURES NEAR NORMAL (POPS ~40% TEMPS ~90) THROUGH THE PERIOD WITH AMPLE LOW LEVEL MOISTURE AND DAYTIME HEATING SUPPORTING SCATTERED SHOWERS AND STORMS ALONG THE SEA BREEZE CIRCULATIONS EACH DAY DURING THE AFTERNOON AND EARLY EVENING HOURS. NOTE...RESIDENTS AND VISITORS OF FLORIDA SHOULD CONTINUE TO CLOSELY MONITOR THE PROGRESS OF GUSTAV THROUGH THE UPCOMING WEEKEND. FOR ADDITIONAL INFORMATION ON GUSTAV...SEE THE LATEST ADVISORIES BEING ISSUED BY THE NATIONAL HURRICANE CENTER. NWS Key West,Fl ....LONG TERM (FRIDAY NIGHT THROUGH TUESDAY)... NO CHANGE IN FORECAST REASONING FROM THE LAST COUPLE OF NIGHTS. THE DEEP LAYERED RIDGE OVER THE FLORIDA PENINSULA AND THE ADJACENT GULF AND ATLANTIC WATERS MAY GRADUALLY ERODE ON THE WESTERN FLANK...WHICH WOULD ALLOW TROPICAL CYCLONE GUSTAV TO TURN NORTHWESTWARD BETWEEN THE EXTREME SOUTHEAST TIP OF CUBA AND THE YUCATAN PENINSULA. THIS WILL ULTIMATELY BE DETERMINED BY EXTENT OF WEAKENING OF THE AFOREMENTIONED RIDGE IN THE EASTERN GULF OF MEXICO. REGARDLESS...CONFIDENCE REMAINS EXTREMELY HIGH THAT THIS TROPICAL SYSTEM WILL NOT IMPACT OUR SERVICE AREA. IN FACT...PENDING ON THE EXACT TRACK AND INTENSITY...STRONG SUBSIDENCE MAY SUPPRESS CONVECTIVE DEVELOPMENT. FOR NOW...WITH DEEPENING AND INCREASING EASTERLY FLOW...WILL MAINTAIN AVERAGE LOW CHANCE POPS ALONG WITH NEAR NORMAL TEMPERATES FOR THIS UPCOMING HOLIDAY WEEKEND. |