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000 FXUS62 KMFL 190127 AFDMFL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 927 PM EDT THU SEP 18 2008 .UPDATE... SCATTERED SHOWER/THUNDERSTORM ACTIVITY THAT DEVELOPED EARLIER TODAY...AS MID-LEVEL SHORTWAVE TROUGH AXIS APPROACHED SOUTH FLORIDA...WILL CONTINUE TO AFFECT MAINLY SOUTHERN PORTIONS OF THE FORECAST AREA OVERNIGHT. DESPITE WESTERLY COMPONENT TO FLOW ALOFT...LATEST VWP DATA FROM KAMX WSR 88-D SUGGESTS THAT INFLUENCE OF STRONG SURFACE RIDGING OVER THE GREAT LAKES REGION HAS ALREADY SPREAD OVER THE REGION...WITH NORTHEAST FLOW THROUGH THE LOWEST 8-10 KFT OF THE TROPOSPHERE. THIS WILL PERSIST OVERNIGHT...AND HAVE PLACED HIGHEST POPS OVER THE GULF WATERS AND ACROSS THE SOUTHERN TIP OF THE PENINSULA TO ACCOUNT FOR RECENT TRENDS IN RADAR IMAGERY. OTHERWISE...ADJUSTED WIND SPEEDS SLIGHTLY OVER THE ATLANTIC WATERS/BISCAYNE BAY/LAKE OKEECHOBEE TO REFLECT RECENT OBSERVATIONS. NO OTHER SIGNIFICANT CHANGES WILL BE MADE WITH THIS UPDATE. 70/DD && .AVIATION DISCUSSION... /ISSUED 817 PM EDT THU SEP 18 2008/ AVIATION...VFR CONDITIONS EXPECTED THROUGH 20/00Z. VCSH LEFT UNTIL 19/03Z FOR THE EAST COAST TERMINALS. A LIGHT NE FLOW AT ALL TERMINALS EXPECTED TO PICK UP TO AROUND 11 KTS BY 19/15Z. LEFT VCTS FOR THE EAST COAST ALSO BY 19/15Z. FOR KAPF...VCSH EXPECTED BY 19/15Z WITH A NE FLOW. /RIVERA .PREV DISCUSSION... /ISSUED 253 PM EDT THU SEP 18 2008/ DISCUSSION...MID/UPPER LEVEL TROUGH DIGGING DEEPER THAN EXPECTED INTO NORTHEAST GULF OF MEXICO AND NORTHERN FLORIDA. THE INFLUENCE THE THE ADVANCING DRYER AIR AND THE DEEPENING TROUGH, HAS ME HESITANT IN LOWERING THE POPS FOR THE REST OF THIS AFTERNOON. SOME OF THE DRIER AIR REACHES SOUTH FLORIDA BY FRIDAY AND HANGS AROUND FOR MOST OF THE WEEKEND. THIS CHANGES THE POP FORECAST A LITTLE. I CHANGED AFTN POPS OF 50 PERCENT FOR THE NEXT 3 AFTNS TO 40 PERCENT AND THAT MAY BE A BIT HIGH. FCSTD SOUNDINGS INDICATE PWAT`S REACHING 1.6" BY FRIDAY AND CLIMBS A BIT SATURDAY AND THEN TO AT LEAST 1.80 INCHES BY SUNDAY. BUT THE MID LEVELS LOOK A BIT WARM THROUGH THE PERIOD SO IF THIS TREND CONTINUES, THE WEEKEND MAY BE BETTER THAN EXPECTED ATTM. BY SUNDAY THE MID LEVEL HIGH PRESSURE BUILDS BACK IN AND PUSHES THE TROUGH NORTH AND EAST. THE LOW LEVEL TROUGH THAT WAS TALKED ABOUT PREVIOUSLY APPROACHING SOUTH FLORIDA EARLY SUNDAY DOESN`T HAVE AS MUCH MOISTURE WITH IT AND MUCH SHALLOWER EASTERLIES. BUT BY TUESDAY AND WEDNESDAY, MUCH DEEPER EASTERLIES RETURN AND PWAT`S CLIMB TO AROUND 2 INCHES AND HAVE UPPED THE POPS FOR THESE DAYS TO BE MORE IN LINE WITH THE MEXMOS. MARINE...WINDS WILL BE NE 5 TO 10 KNOTS TNGT THROUGH FRIDAY NIGHT AND THEN BASICALLY E 5 TO 10 KNOTS SAT THROUGH TUES. SPEEDS WILL BE A LITTLE HIGHER MONDAY NIGHT AND TUES SOUTHERN ATLANTIC WATERS AND SEAS WILL BE UP TO 4 FEET IN THE GULF STREAM. LOOKED AT THE WNAWAVE MODEL AND NOTICED A NE SIGNIFICANT WAVE HEIGHT OF 1.5 METERS FOR THIS WEEKEND. WITH THE MID LEVEL TROUGH MOVING OUT, IT DOES PRODUCE A LOW BUT NOT AS STRONG AS PREVIOUS RUNS SO WILL HAVE TO WAIT AND SEE IF THE WAVE WATCH MODEL CONTINUES THIS SCENARIO. FIRE WEATHER...NO CONCERNS HERE AS THE MINIMUM RH`S WILL BE ABOVE CRITICAL VALUES. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 76 88 75 89 / 30 40 30 40 FORT LAUDERDALE 78 89 77 88 / 40 40 30 40 MIAMI 78 90 77 89 / 50 40 30 40 NAPLES 73 90 73 90 / 50 40 20 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. GM...NONE. && $$ LONG TERM...70/DD SHORT TERM/AVIATION...47/RHG