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000 FXUS62 KMFL 250538 AFDMFL AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MIAMI FL 138 AM EDT THU SEP 25 2008 .AVIATION...KEPT VCSH FOR ALL EASTERN TERMINAL THROUGH THE NIGHT AS SHRA CONTINUE TO MOVE IN FROM ATLANTIC, AND KEPT APF DRY, BUT MOSTLY VFR CONDITIONS ARE STILL EXPECTED AT ALL TERMINAL WITH BRIEF PERIOD OF MVFR POSSIBLE. WINDS ARE EXPECTED TO REMAIN GENERALLY NORTHEASTERLY THROUGH THE PERIOD AS WELL EXPECT FOR AT APF WHERE A SEA BREEZE MAY DEVELOP DURING THE AFTERNOON. /TINGLER && .PREV DISCUSSION... /ISSUED 928 PM EDT WED SEP 24 2008/ UPDATE...LATEST ANALYSIS SHOWS PERSISTENT CONVERGENT BANDS OFFSHORE MIAMI DADE WITH PERSISTENT SHOWER ACTIVITY MOVING ONSHORE ACROSS PORTIONS OF EASTERN MIAMI DADE. RADAR ESTIMATES CLOSE TO AN INCH OVER THE PAST COUPLE OF HOURS WITH THESE SHOWERS ACROSS PORTIONS OF EAST CENTRAL MIAMI DADE COUNTY. THE LOCAL WRF MODEL INDICATES THIS ACTIVITY COULD LINGER INTO THE MORNING HOURS ON AND OFF AS FLOW INLAND DECOUPLES AND COASTAL CONVERGENCE PERSISTS. SO UPDATED FORECAST TO REFLECT SCATTERED SHOWERS INTO THE EARLY MORNING HOURS FOR BROWARD AND MIAMI DADE COUNTIES. ON THE MARINE SIDE BUOYS OFFSHORE EAST CENTRAL FLORIDA INDICATE SWELLS OF 9 TO 12 FEET WITH PERIODS OF 13 TO 14 SECONDS. THAT SHOULD RESULT IN SWELLS OF AROUND 6 FEET (HIGHER OFFSHORE) WITH A PERIOD OF 15 TO 17 SECONDS REACHING THE PALM BEACH COAST IN ABOUT 7 TO 8 HOURS. BUT SINCE THOSE CONDITIONS HAVE BEEN OBSERVED SINCE EARLIER TODAY, THESE SWELLS SHOULD BE ABOUT TO BEGIN IF NOT ALREADY IMPACTING PORTIONS OF THE COAST. THOSE KIND OF SWELLS SHOULD RESULT IN BREAKERS OF ABOUT 10 FEET STARTING TONIGHT AND THROUGH TOMORROW. SWELLS SHOULD BE SLIGHTLY LESS FARTHER SOUTH ACROSS BROWARD COUNTY BUT GIVEN THE NORTHERLY COMPONENT OF THE SWELLS THEY WILL LIKELY STILL EXPERIENCE ROUGH SURF. SO WILL PUT UP A COASTAL STATEMENT FOR BROWARD FOR RIP CURRENTS AND MINOR BEACH EROSION. PREV DISCUSSION... /ISSUED 738 PM EDT WED SEP 24 2008/ UPDATE...KPBI, KFXE AND KFLL WILL STAY PREDOMINANTLY VFR MOST OF THE NIGHT. KOPF, KMIA AND KTMB WILL BE TEMPO IN MVFR SHOWERS TIL ARND 03Z. KAPF WILL BE VFR THROUGH THE PERIOD. PUT IN A VCSH AFTER 07-09Z FOR ALL EAST TERMINALS. WINDS WILL BE GUSTY IN SHOWERS UNTIL 03Z FOR THE EAST TERMINALS. PREV DISCUSSION... /ISSUED 235 PM EDT WED SEP 24 2008/ DISCUSSION... SCATTERED SHOWERS...SOME WITH HEAVY RAINFALL CONTINUE TO PUSH SLOWLY SOUTHWEST ACROSS SOUTH FLORIDA EARLY THIS AFTERNOON. THESE SHOWERS ARE BEING DRIVEN BY STRONG NORTHEAST WINDS JUST NORTH OF THE LOCAL AREA ALONG THE EAST CENTRAL FLORIDA COAST AND ADJACENT COASTAL WATERS WHICH ARE CONVERGING WITH WEAKER WINDS ACROSS THE LOCAL AREA AS THE STRONG NORTHEAST FLOW HAS FAILED TO MAKE MUCH HEADWAY INTO SOUTH FLORIDA. MODELS SEEM TO HAVE HAD DIFFICULTY IN HANDLING THE EVOLUTION OF THIS PATTERN AS CAN BE EXPECTED WITH A COMPLEX SYSTEM OFF THE CAROLINAS. AS A RESULT I`VE GONE SLIGHTLY ABOVE GUIDANCE FOR RAIN CHANCES TONIGHT AS AT LEAST SOME ONSHORE COMPONENT TO THE LOW LEVEL FLOW WILL REMAIN THIS EVENING BEFORE A DRAINAGE WIND SETS UP OVERNIGHT CREATING CONVERGENCE ALONG THE EAST COAST...WHICH COULD LEAD TO MORE SHOWER GENERATION. WESTERN AREAS SHOULD DRY OUT BY THIS EVENING WITH MORE STABILITY TAKING HOLD AND DRIER AIR FILTERING IN FROM THE NORTH IN THE LOW LEVELS. TEMPS WILL BE SLIGHTLY COOLER TONIGHT ESPECIALLY ACROSS THE INTERIOR...WITH LOWS IN THE MID TO UPPER 60S VERSUS LOWER 70S ACROSS THE EAST COAST METRO AREAS. FOR THURSDAY AND FRIDAY...LIGHT WINDS AND PARTLY CLOUDY SKIES WILL BEGIN THE DAYS...BUT MODELS NOW SUGGEST SOME LOW-LEVEL MOISTURE WILL REMAIN ACROSS SOUTHERN AREAS. THIS COULD COMBINE WITH A WEAK AFTERNOON SEA BREEZE TO SET OFF AN ISOLATED SHOWER OR TWO DESPITE INCREASING MID-LEVEL SUBSIDENCE. NORTHWEST INTERIOR AREAS AS WELL AS COLLIER COUNTY MAY REMAIN DRY AS THE STRONGEST PUSH OF DRY AIR IMPACTS THESE LOCATIONS...WITH DEWPOINTS MIXING DOWN THROUGH THE 60S WHICH WILL BE A NICE BREAK FROM THE HUMIDITY...WITH EVEN SOME SUBTLE BUT NOTICEABLY LOWER HUMIDITY LEVELS ACROSS THE EAST COAST. LOW TEMPS COULD DIP INTO THE LOWER 60S ACROSS SOME OF THE NORMALLY COOLER NORTHWEST INTERIOR AREAS THURSDAY AND FRIDAY NIGHTS...WITH LOWER IN THE UPPER 60S TO AROUND 70 ACROSS THE EAST COAST METRO AND NAPLES AREAS. THE GFS HAS CHANGED SOME ON THE 12Z RUN THIS MORNING...MOVING DEEP-LAYERED MOISTURE AND THE REMNANT SURFACE TROUGH BACK NORTH THROUGH THE REGION A LITTLE QUICKER SATURDAY AND SUNDAY WITH INCREASING RAIN CHANCES. WILL NOT MAKE MANY ADJUSTMENTS TO THE WEEKEND FORECAST JUST YET AS THIS IS THE FIRST HINT OF THIS. MODERATE SWELLS WITH LARGE BREAKERS CAN BE SEEN ALONG THE NORTHERN PALM BEACH COAST AT JUPITER INLET EARLY THIS AFTERNOON WITH AN INCREASE NOTED THROUGH THE DAY SO FAR. UPSTREAM OBS SHOW 10FT/12S SWELLS AT BUOYS 41009 AND 41010 WHICH HAVE BEEN PRETTY STEADY THROUGH THE DAY. THIS SHOULD LEAD TO PEAK SWELLS BETWEEN 5 AND 6FT TONIGHT AND TOMORROW ALONG COASTAL PALM BEACH COUNTY BEFORE DECREASING TOMORROW NIGHT. SOME MINOR COASTAL FLOODING WILL BE POSSIBLE AT THE HIGH TIDE CYCLES ESPECIALLY AROUND 5AM TOMORROW MORNING AND BEACH EROSION IS POSSIBLE ESPECIALLY IN AREAS MADE VULNERABLE BY SWELL EVENTS THE PAST FEW YEARS. CURRENT FORECAST AND HIGH SURF ADVISORY REFLECT THE CURRENT AND EXPECTED CONDITIONS WELL. MARINE... NO CHANGES TO THE MARINE FORECAST IN THE SHORT TERM. WINDS CONTINUE TO BLOW AROUND 20KTS SUSTAINED ON LAKE OKEECHOBEE WITH HIGHER GUSTS ESPECIALLY IN RAIN. CURRENT FORECAST HAS SEAS PEAKING AROUND 10-11FT ACROSS THE GULF STREAM OFFSHORE PALM BEACH COUNTY LATE TONIGHT/TOMORROW AND GIVEN CURRENT UPSTREAM TRENDS AND WAVE WATCH GUIDANCE WHICH HAS BEEN VERY CONSISTENT AND ACCURATE SO FAR THIS SEEMS REASONABLE. FOR FRIDAY AND SATURDAY...I SLOWED THE RATE OF DECAY IN THE SEAS SOME AS WAVE WATCH SHOWS SWELLS LINGERING A BIT LONGER ESPECIALLY ACROSS THE NORTHERN ATLANTIC WATERS. FIRE WEATHER... DEWPOINTS SHOULD DECREASE TOMORROW AND LINGER IN THE LOWER 60S ACROSS NORTHWEST INTERIOR SECTIONS INTO FRIDAY AFTERNOON. THIS COULD LEAD TO RH`S DROPPING TO AROUND 40 PERCENT FOR AN HOUR OR TWO AROUND PEAK HEATING...BUT IF EVEN DRIER AIR CAN MIX DOWN FROM JUST ABOVE THE SURFACE THEN RH`S COULD DROP TO SLIGHTLY LOWER LEVELS. && .PRELIMINARY POINT TEMPS/POPS... WEST PALM BEACH 87 67 87 71 / 10 10 10 20 FORT LAUDERDALE 87 70 87 72 / 10 10 10 20 MIAMI 87 71 86 72 / 10 10 10 20 NAPLES 86 67 88 71 / 10 10 10 20 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...HIGH SURF ADVISORY UNTIL 8 AM EDT FRIDAY FOR FLZ168. AM...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 AM EDT FRIDAY FOR AMZ650-AMZ651-AMZ670-AMZ671. SMALL CRAFT ADVISORY UNTIL 4 AM EDT EARLY THIS MORNING FOR AMZ610. GM...NONE. && $$