AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
639 AM EST TUE DEC 4 2012

.AVIATION…
FORECAST CONTINUES TO BE MAINLY VFR WITH VERY SHORT LIVED MVFR
POSSIBLE ALONG WITH ISOLATED RAIN SHOWERS. THIS IS DUE TO HIGH
PRESSURE TO THE NORTH BRINGING A MOIST…EASTERLY FLOW TO THE
REGION. LIGHT WINDS EARLY THIS MORNING WILL INCREASE TO 10 TO 15
KTS WITH OCCASIONAL HIGHER GUSTS BY LATE MORNING.

&&

.PREV DISCUSSION… /ISSUED 208 AM EST TUE DEC 4 2012/

DISCUSSION…DEEP LAYER RIDGE WILL CONTINUE ACROSS SOUTH FLORIDA
THROUGH WEDNESDAY WITH THE AXIS OF THE MID LAYER RIDGE STRETCHING
FROM THE FLORIDA STRAITS AND SOUTH FLORIDA INTO THE ATLANTIC. THE
SURFACE RIDGE IS LOCATED FROM THE SOUTHEAST STATES AND NORTH
FLORIDA INTO THE ATLANTIC. THUS, THE EASTERLY FLOW WILL ALSO
CONTINUE WITH A FEW SHOWERS FROM TIME TO TIME. THE EAST WIND WILL
DIMINISH SOMEWHAT ON WEDNESDAY AS THE SURFACE RIDGE SHIFTS
SLIGHTLY SOUTH IN RESPONSE TO A WEAKENING COLD FRONT THAT WILL
MOVE INTO NORTHERN GEORGIA WHICH IN TURN WILL RELAX THE GRADIENT
ACROSS OUR AREA. NEAR AVERAGE TEMPERATURES ARE EXPECTED WITH
AFTERNOON MAXIMUMS IN THE UPPER 70S TO AROUND 80 AND MINIMUMS IN
THE MID 50S TO MID 60S.

THERE WILL BE A NEED TO MAKE A SLIGHT CHANGE TO THE FORECAST
BEYOND THE WEDNESDAY TIME FRAME. THE NAM, GFS AND ECMWF HAVE ALL
KEYED IN ON A WEAK MID LEVEL TROUGH THAT WILL MOVE INTO THE
SOUTHERN PLAINS STATES TODAY THEN INTO THE NORTHEAST GULF
WEDNESDAY NIGHT AND ACROSS SOUTH FLORIDA ON THURSDAY. AS THIS
OCCURS, MOISTURE WILL BEGIN TO RETURN FROM THE CARIBBEAN AHEAD OF
THE TROUGH. HOWEVER, THIS IS WHERE THE SIMILARITIES IN THE MODELS
END WITH ALL THREE HAVING A DIFFERENCE IN OPINION AS TO WHAT THE
EFFECTS ON SOUTH FLORIDA WILL BE WITH THIS FEATURE. SOME COOLING
ALOFT IS EXPECTED WHICH WILL DESTABILIZE THE ATMOSPHERE WITH THE
GFS BEING THE MOST AGGRESSIVE AND IT SHOWS A GOOD CHANCE FOR
THUNDER TO OCCUR EITHER LATE WEDNESDAY NIGHT OR THURSDAY. THE NAM
IS MUCH LESS AGGRESSIVE KEEPING MOST OF THE DEEP LAYER MOISTURE
WELL TO OUR EAST OVER THE BAHAMAS. THE ECMWF LIES IN BETWEEN
SHOWING MARGINAL MOISTURE AND INSTABILITY. DUE TO THESE
DISCREPANCIES, WILL INCREASE THE POPS FOR WEDNESDAY NIGHT AND
THURSDAY BUT WILL GO MUCH LOWER THAN THE MAV STAYING CLOSER TO THE
MET NUMBERS. ALSO, DO NOT PLAN TO ADD THUNDER AT THIS TIME BUT
THIS WILL NEED TO BE MONITORED IN LATER SHIFTS AS THE MODELS COME
IN CLOSER AGREEMENT TO THE EVOLUTION OF THIS TROUGH.

LOOKING INTO THE EXTENDED PERIOD FOR LATE THIS WEEK AND INTO EARLY
NEXT WEEK, AS THE MID LEVEL TROUGH LIFTS TO THE EAST THURSDAY NIGHT
SOUTH FLORIDA WILL RETURN TO A NEAR ZONAL FLOW PATTERN WITH A
SURFACE RIDGE REBUILDING ACROSS NORTH FLORIDA WITH A DRY PATTERN
ONCE AGAIN SETTLING IN OVER THE REGION.

MARINE…THE EAST WIND WILL SLOWLY BE DIMINISHING THROUGH THE
MIDDLE OF THIS WEEK AS THE PRESSURE GRADIENT RELAXES LEADING TO
CALMER SEAS AND LESSER RISK OF RIP CURRENTS AT THE BEACHES. HIGH
PRESSURE WILL BUILD AGAIN LATE THIS WEEK INTO THE WEEKEND WITH
RETURN TO A STRONGER EASTERLY FLOW.

FIRE WEATHER…NO PROBLEMS OR CONCERNS AS LOW LEVEL MOISTURE
REMAINS AMPLE WITH RELATIVE HUMIDITIES STAYING WELL ABOVE CRITICAL
THRESHOLDS.