[Printable]
233 FXUS62 KMFL 031310 AAB AFDMFL AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE MIAMI FL 910 AM EDT THU OCT 3 2013 .UPDATE... NEWLY TROPICAL STORM KAREN HAS DEVELOPED IN THE SOUTHEAST GULF OF MEXICO THIS MORNING WITH A TROUGH OF LOW PRESSURE EXTENDING EAST INTO SOUTH FLORIDA. THIS TROUGH OF LOW PRESSURE WAS SEPARATING THE TROPICAL MOISTURE OVER THE SOUTHERN PORTIONS OF SOUTH FLORIDA WITH THE DRIER AIR OVER THE NORTHERN PORTIONS OF SOUTH FLORIDA. KAREN IS FORECAST BY THE NATIONAL HURRICANE CENTER TO MOVE NORTH-NORTHWEST INTO THE CENTRAL GULF OF MEXICO THROUGH TONIGHT. THIS WILL ALLOW FOR THE TROUGH OF LOW PRESSURE TO BE NEARLY STATIONARY OVER SOUTH FLORIDA TODAY. SO WILL CONTINUE TO SHOW THE LOW END POPS OVER THE LAKE OKEECHOBEE REGION INCREASING AS YOU GO SOUTH TO LIKELY POPS OVER THE SOUTHERN PORTION OF SOUTH FLORIDA. THE STEERING FLOW WILL ALSO BE LIGHT FROM THE EASTERLY DIRECTION TODAY WHICH WILL CAUSE THE STORMS TO BE SLOW MOVERS. SO ANY STORMS THAT DO DEVELOP WILL BE CAPABLE OF PRODUCING HEAVY RAINFALL TODAY. METRO MIAMI-DADE COUNTY HAS ALSO RECEIVED BETWEEN 2 TO 3 INCHES OF RAINFALL IN THE LAST 24 HOURS OVER THE NORTHERN PORTION TO 6 TO 9 INCHES OVER THE SOUTHERN PORTION. SO THE GROUNDS ARE VERY SATURATED. IF MORE HEAVY RAINFALL STARTS TO OCCUR OVER THIS AREA TODAY FROM THE THUNDERSTORMS...THEN A FLOOD WATCH MAYBE NEEDED FOR THE METRO PORTION OF MIAMI-DADE COUNTY. REST OF THE FORECAST LOOKS GOOD AT THIS TIME AND NO OTHER CHANGES ARE PLANNED. && .UPDATE...54/BNB .PREV DISCUSSION... /ISSUED 746 AM EDT THU OCT 3 2013/ AVIATION... CONDITIONS SHOULD BY-AND-LARGE REMAIN AT VFR...BUT SCATTERED TO NUMEROUS SHOWERS AND A FEW THUNDERSTORMS WILL IMPACT ALL EXCEPT KPBI DURING THE DAY. PERIODS OF SUB-VFR VSBY/CIG CAN BE EXPECTED WITH THIS ACTIVITY. LEFT VCSH OUT OF APF UNTIL 14Z...WITH VCSH BEGINNING AT 12Z FOR BROWARD AND MIAMI-DADE TERMINALS. WINDS WILL BE EAST-NORTHEAST AT 5-10 KTS THIS MORNING...INCREASING SLIGHTLY THIS AFTERNOON...THEN DIMINISHING AGAIN AND LIKELY BECOMING ESE OVERNIGHT. && PREV DISCUSSION... /ISSUED 449 AM EDT THU OCT 3 2013/ DISCUSSION... THE HEAVY RAINS THAT AFFECTED THE METRO AREAS OF EASTERN MIAMI DADE COUNTY EARLIER WEDNESDAY EVENING HAVE SUBSIDED WITH ONLY A FEW ISOLATED SHOWERS CURRENTLY NOTED ACROSS THE REGION. ALTHOUGH THE SHOWERS HAVE SUBSIDED...LINGERING URBAN FLOODING HAS BEEN REPORTED ACROSS THE KENDALL AREA OF MIAMI DADE COUNTY WITH AN URBAN FLOOD ADVISORY IN EFFECT UNTIL LATER THIS MORNING. THE RECENT GUIDANCE CONTINUES TO INDICATE A SHARP SOUTH TO NORTH MOISTURE GRADIENT ACROSS THE REGION....WITH DEEPER TROPICAL MOISTURE ACROSS THE SOUTHERN HALF OF THE PENINSULA AND ADJACENT WATERS AND LESS MOISTURE ACROSS THE NORTHERN THIRD OF THE PENINSULA. THIS IS CONSISTENT WITH RECENT SATELLITE TRENDS OF THE PWAT ACROSS THE REGION. THE SOUTH TO NORTH GRADIENT IS EXPECTED TO CONTINUE TODAY WITH FORECAST PWAT`S FOR THE SOUTHERN PORTIONS OF THE PENINSULA IN EXCESS OF TWO INCHES AND ACROSS THE NORTHEASTERN PORTIONS AROUND 1.6 INCHES. GIVEN THIS FEATURE...THE FORECAST FOR TODAY INDICATES A SOUTH TO NORTH GRADIENT IN RAINFALL POTENTIAL WITH THE GREATEST COVERAGE OF SHOWERS EXPECTED ACROSS THE SOUTHERN HALF OF THE PENINSULA AND ADJACENT WATERS AND MORE ISOLATED ACTIVITY ACROSS THE NORTHERN PORTIONS. IN ADDITION...THE HEAVY RAINS THAT AFFECTED MIAMI DADE COUNTY YESTERDAY EVENING AND EARLIER THIS MORNING WILL LIKELY LEAVE A LINGERING BOUNDARY THAT COULD SPAWN ADDITIONAL SHOWERS TODAY IN THE SAME GENERAL AREA. RECENT MESO-SCALE MODEL RESULTS INDICATE THAT IS A POSSIBLE SCENARIO TODAY. GIVEN ALL THESE FACTORS...THERE COULD BE THE POTENTIAL FOR ISOLATED AREAS TO RECEIVE LOCALLY HEAVY RAINFALL TODAY WITH THE MAIN AREAS OF CONCERN BEING THE SOUTHERN PORTIONS OF THE PENINSULA WHERE NUMEROUS SHOWERS ARE FORECAST WITH THUNDERSTORM ACTIVITY EXPECTED TO BE ISOLATED. BY FRIDAY THE DEVELOPING AREA OF LOW PRESSURE IN THE NORTHWEST CARIBBEAN IS FORECAST TO ENTER THE CENTRAL GULF WITH THE MOISTURE GRADIENT SHIFTING TO A MORE WEST TO EAST ORIENTATION WITH THE DEEPER MOISTURE SHIFTING TO THE GULF REGION AND THE WESTERN PORTIONS OF THE SOUTH FLORIDA PENINSULA. THE FORECAST FOR SHOWERS FOLLOWS THIS GRADIENT WITH SCATTERED SHOWERS AND THUNDERSTORMS BY THE AFTERNOON WITH THE GREATEST COVERAGE EXPECTED IN THE INTERIOR AND WESTERN PORTIONS OF THE INTERIOR. A SIMILAR SCENARIO IS EXPECTED ON SUNDAY ALTHOUGH COVERAGE OF AFTERNOON SHOWERS AND THUNDERSTORMS IS EXPECTED TO BE LESS. BY SUNDAY AND INTO THE EARLY PORTIONS OF NEXT WEEK A CHANCE OF MAINLY AFTERNOON SHOWERS AND THUNDERSTORMS WILL CONTINUE ACROSS THE REGION AS THE AFOREMENTIONED DEVELOPING LOW PRESSURE SYSTEM IS FORECAST TO RAPIDLY ACCELERATE TO THE NORTHEAST AS IT GETS EMBEDDED IN A LARGE AMPLITUDE UPPER LEVEL TROUGH DEVELOPING ACROSS THE NORTHERN GULF. THIS SCENARIO WOULD CONTINUE TO BRING DEEPER MOISTURE ACROSS THE REGION WITH A MORE SOUTHERLY FLOW...ALLOWING FOR AFTERNOON SHOWERS AND THUNDERSTORMS. BUT OF COURSE THERE IS THE USUAL UNCERTAINTY AND WILL WAIT AND SEE HOW THIS SCENARIO PLAYS OUT AND REFINE THE FORECAST ACCORDINGLY. MARINE... WINDS ACROSS THE REGIONAL WATERS TODAY INTO THE UPCOMING WEEKEND ARE FORECAST TO BE MAINLY EASTERLY IN THE 10 TO 15 KNOT RANGE WITH REGIONAL SEAS OF 3 FEET OR LESS THROUGH THAT PERIOD. ALTHOUGH THERE IS SOME UNCERTAINTY IN THE EXTENDED FORECAST...SIMILAR CONDITIONS ARE FORECAST. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 87 76 87 76 / 20 20 20 10 FORT LAUDERDALE 85 77 87 78 / 50 20 20 10 MIAMI 87 77 87 77 / 60 20 30 10 NAPLES 88 74 88 74 / 60 40 50 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ DISCUSSION/MARINE/FIRE...57/DG AVIATION/RADAR...13/SI