FXUS62 KMFL 042010
AFDMFL
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
310 PM EST FRI DEC 4 2009
.DISCUSSION...A QUASI-STATIONARY FRONTAL BOUNDARY IS CURRENTLY
STRETCHED FROM THE YUCATAN ACROSS S FL AND INTO THE ATLANTIC WHILE
MULTIPLE PERTURBATIONS IN THE UPPER FLOW CONTINUE TO MOVE ACROSS FL
AROUND THE BASE OF THE TROUGH OVER THE SOUTHERN AND CENTRAL
PLAINS. THIS FRONT IS CURRENTLY LOCATED FROM AROUND EVERGLADES
CITY TO JUST NORTH OF WEST PALM BEACH. THIS SHALLOW AND ONLY
SLIGHTLY COOL AIRMASS DID NUDGE DOWN TO MIA EARLY THIS MORNING AS
NOTED ON THE 12 MFL SOUNDING BUT AS SINCE PUSHED BACK NORTH, AND
WILL CONTINUE TO DO SO THIS EVENING AND TONIGHT AS A SURFACE LOW
GETS ORGANIZED OVER THE WESTERN GULF AND PUSHES EAST. ALSO OF NOTE
IS THE VERY SOUPY 2.2" PWAT ON THE MORNING SOUNDING AND THE NOW 77
DEWPOINT AT MIA AS WARM AND MOIST AIR PUSH NORTH AT THE SURFACE
BEHIND THE WARM FRONT. AN EVEN MORE INTERESTING IS THAT IF THE 12Z
MFL SOUNDING IS MODIFIED TO THE CURRENT T/TD FROM MIA IT YIELD A
WHOPPING 5,100 J/KG CAPE AND A LI OF -9.3!... LUCKILY THE BEST
SURFACE CONVERGENCE HAS LIFTED NORTH WITH THE FRONT, AND A BIT OF
WARM/DRY AIR HAS MOVED INTO THE MID LVLS SUPPRESSING WHAT WOULD
OTHERWISE BE A VERY ACTIVE AFTERNOON, BUT A FEW STORMS CAN STILL
NOT BE RULED OUT IN BROWARD AND MIAMI-DADE COUNTIES. THE BIGGER
FOCUS FOR PRECIP THROUGH THE AFTERNOON AND EARLY EVENING WILL BE
FROM AROUND APF TO THE LAKE REGION, BEHIND THE FRONT WHERE
ISENTROPIC LIFT WILL KEEP THE RAIN GOING. LATE TONIGHT S FL WITH
BE IN A FAVORABLE QUAD OF THE JET ALONG WITH GOOD BACKING OF
WINDS... THIS WILL LEAD TO A SLIGHT RISK OF SVR WX NAMELY
TORNADOES. THIS WILL MAINLY OCCUR CLOSER TO THE FRONTAL BOUNDARY...
AROUND THE LAKE REGION... WHERE LIFT WILL BE THE GREATEST. AS THE
LOW TRAVERSES THE GULF AND THE SE STATES TOMORROW THIS WILL ALLOW
THE FRONT TO PUSH BACK SOUTH AND ALSO ALLOW THE TOR THREAT TO TURN
MORE INTO A WIND THREAT AS THE FRONT NEARS THE SE COAST METRO.
BEHIND THE FRONT A MODERATE AMOUNT OF CAA WILL OCCUR WITH LO TEMPS
DROPPING ABOUT 10 DEGREES ON SUN MORN COMPARED TO THE PRIOR 24HRS.
THROUGH THE REMAINDER OF THE PERIOD THE TROF RETURNS NORTH WITH A
MODEST INCREASE IN POPS FOR MON FOLLOWED BY A RETURN IN THE SE
FLOW INTO THE END OF THE WEEK AS ANOTHER SYSTEM ORGANIZES IN THE
PLAINS. THIS NEXT FRONT MAY APPROACH THE AREA THURS OR EARLY FRI.
&&
.AVIATION...BASED ON LATEST RADAR TRENDS...FEEL THAT LIGHT/MODERATE SHRA
ACTIVITY WILL BE CONFINED TO APF/PBI FOR REMAINDER OF
AFTERNOON...AND WILL INCLUDE VCSH FOR ONLY THESE TERMINALS.
OTHERWISE...EXPECT PREVAILING MVFR CONDS WITH BKN SC DECK NOW
BEING REPORTED AT MOST TERMINALS AND CIGS GENERALLY RANGING FROM
1500-2500 FT. SKY CONDS MAY IMPROVE FROM LATE AFTERNOON THRU EARLY
EVENING...BUT EXPECT DETERIORATION ONCE AGAIN EARLY SATURDAY
MORNING AS CONVECTION DEVELOPS INVOF SURFACE LOW MOVING ACROSS
CENTRAL FLORIDA. THREAT FOR SIGNIFICANT TSRA DEVELOPMENT WILL
INCREASE AS EARLY AS 06Z APF/PBI...WITH CHANCES INCREASING FURTHER
TO THE SOUTH (BROWARD AND MIAMI-DADE TERMINALS) BETWEEN 09-11Z.
WILL UTILIZE VCTS/CB FOR NOW AND INDICATE MVFR CIGS...WITH GUSTY
SSE WINDS PREVAILING OUTSIDE OF STORMS. PREFRONTAL TROUGH WILL BE
PUSHING ACROSS SOUTH FLORIDA AFTER DAWN...WITH WINDS SHIFTING TO
SOUTHWEST AND INCREASING TO 15G25 KNOTS. BEST ESTIMATE ON TIMING
IS 14Z APF/PBI...16Z FLL/FXE...AND 17Z MIA/TMB/OPF. ALTHOUGH CIGS
MAY IMPROVE TO VFR DURING THIS PERIOD...WILL MAINTAIN VCTS/CB AS
THERE AS UNCERTAINTY ON WHEN STORM CHANCES WILL END.
70/DD
&&
.MARINE...A FRONTAL BOUNDARY REMAINS STALLED FROM AROUND WEST PALM
BEACH TO EVERGLADES CITY... NORTH OF THE BOUNDARY WINDS ARE NE AND
SOUTH OF THE BOUNDARY, SE WINDS. SPEEDS ARE GENERALLY LESS THAN
15KTS. THIS BOUNDARY WILL SLOWLY LIFT NORTH TONIGHT THEN PUSH
SOUTH AND THROUGH THE AREA SATURDAY. WINDS MAY BRIEFLY INCREASE TO
AROUND 20KTS BEHIND THE FRONT TOMORROW, BUT DURATION IS SHORT AND
WILL ALLOW THIS TO FALL TO NEXT SHIFTS TO EXAMINE NEED OF SCA.
LATE IN THE WEEKEND A LOW MAY DEVELOP OFF THE N FL COAST AND ZIP
NE POSSIBLY SENDING SMALL SWELL INTO THE COASTAL ATLANTIC THROUGH
THE FIRST PART OF THE COMING WEEK.
&&
.FIRE WEATHER...NO PROBLEMS OR CONCERNS.
&&
.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH 71 81 55 76 / 60 80 10 10
FORT LAUDERDALE 72 82 60 76 / 40 70 10 10
MIAMI 73 83 61 78 / 40 60 10 10
NAPLES 68 76 53 74 / 90 80 - -
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&
$$
LONG TERM...04/AT
SHORT TERM/AVIATION...70/DD
