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000
FXUS62 KMFL 120124
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
924 PM EDT SAT MAY 11 2013

.DISCUSSION...
A QUICK UPDATE ON THE FORECAST TO ADJUST POPS AND WIND FOR WHAT IS
HAPPENING IN THE SHORT TERM. ALL ELSE IS ON TRACK.

&&

.PREV DISCUSSION... /ISSUED 731 PM EDT SAT MAY 11 2013/

UPDATE...
THUNDERSTORMS CONTINUE TO MOVE EASTWARD, TOWARDS THE MIAMI/DAD
METRO AREA. HAVE UPDATED THE FORECAST TO REFLECT THIS FOR THE NEXT
FEW HOURS. ALSO HAVE REDUCED POPS OVER PALM BEACH COUNTY TO SHOW
SCATTERED COVERAGE. COVERAGE SHOULD REDUCE WITHIN THE NEXT THREE
HOURS AS DAYTIME HEATING IS LOST.

PREV DISCUSSION... /ISSUED 728 PM EDT SAT MAY 11 2013/

AVIATION...
ONGOING CONVECTION JUST INLAND OF THE BROWARD AND MIAMI-DADE
TERMINALS WILL CONTINUE TO DRIFT EASTWARD TOWARD THE TERMINALS
THROUGH THE MID-EVENING HOURS. HAVE INCLUDED TEMPO GROUPS TO
SUPPORT THIS AND WILL UPDATE IF NEEDED. THIS ACTIVITY SHOULD TREND
DOWN THROUGH THE MID TO LATE EVENING HOURS. ELSEWHERE...ANOTHER
QUIET NIGHT IS ANTICIPATED WITH WINDS BECOMING LIGHT. SIMILAR
CONDITIONS EXPECTED ONCE AGAIN ON SUNDAY WITH AFTERNOON CONVECTION
FAVORING THE EAST COAST WITH THE SW FLOW IN PLACE UP TO 10 KFT.

PREV DISCUSSION... /ISSUED 210 PM EDT SAT MAY 11 2013/

CORRECTED LONG RANGE TIME FRAME...

SHORT TERM (TONIGHT THROUGH MONDAY NIGHT)...
SOUTH FLORIDA IS CURRENTLY UNDER NEAR ZONAL FLOW WITH A MID LEVEL
RIDGE TO THE EAST AND A LARGE CUT-OFF LOW OVER NORTHERN MEXICO. A
FAST MOVING WAVE IS EMBEDDED IN THE ZONAL FLOW PATTERN CURRENTLY
MOVING INTO THE FLORIDA PANHANDLE WITH A LARGE CLUSTER OF CONVECTION
ASSOCIATED WITH IT. THE PROXIMITY OF THIS WAVE ALONG WITH PLENTY OF
SUNSHINE EARLY TODAY AND INSTABILITY WILL CAUSE ANOTHER ROUND OF
LATE AFTERNOON AND EARLY EVENING THUNDERSTORMS DEVELOPING OVER THE
INTERIOR AND THEN WILL DRIFT BACK TOWARDS THE EAST COAST. AT THE
SURFACE, A RIDGE IS LOCATED ACROSS SOUTH FLORIDA PRODUCING A LOW
LEVEL SOUTHERLY FLOW WHICH WILL TEND TO KEEP THE INITIATION OF
CONVECTION WELL INLAND FROM THE COASTS OF MIAMI-DADE AND COLLIER
COUNTIES.

LOOKING UPSTREAM, A MAJOR MID LEVEL TROUGH WILL DEEPEN ACROSS
EASTERN NORTH AMERICA THROUGH MONDAY WITH ITS ASSOCIATED WEAKENING
COLD FRONT MOVING INTO NORTH FLORIDA ON SUNDAY AND INTO SOUTH
FLORIDA BY LATE MONDAY. THIS WILL PROVIDE A CONTINUED THREAT FOR
MAINLY AFTERNOON AND EVENING CONVECTION FAVORING THE INTERIOR AND
EAST COAST. FORECAST SOUNDINGS SHOW SLOW STORM MOTION AGAIN ON
SUNDAY BUT A STRONGER WESTERLY STEERING FLOW ON MONDAY AS THE TROUGH
DEEPENS FURTHER. THE PWAT IS ALSO FORECAST TO REMAIN IN THE RANGE OF
1.5-1.7 INCHES WHICH IS ABOVE THE AVERAGE FOR MID MAY. IN ADDITION,
500 MB TEMPERATURES ARE FORECAST TO HOVER AROUND -10 TO -11 CELSIUS
THROUGH MONDAY AND THIS IS ONE TO TWO DEGREES BELOW THE AVERAGE SO
ALSO ADDING FUEL TO THE MIX. THE COLD FRONT WILL PUSH OFF THE
SOUTHEAST COAST MONDAY EVENING AND BRING A REFRESHING FEELING TO
THE AIR WITH TEMPERATURES FALLING TO ABOUT 8-10 DEGREES BELOW
NORMAL MONDAY NIGHT.

LONG TERM (TUESDAY THROUGH SATURDAY)... THE TROUGH WILL BEGIN TO
SHIFT EAST ON TUESDAY WITH A RIDGE BUILDING ACROSS THE GULF OF
MEXICO WHICH WILL FILTER A MUCH DRIER AIR MASS INTO SOUTH FLORIDA
CONTINUING THROUGH MUCH OF THE WEEK. THERE IS HOWEVER ONE
DISCREPANCY IN THE LONG RANGE MODELS BY THE END OF THE FORECAST.
BOTH THE ECMWF AND GFS SHOW THE CUT-OFF LOW CURRENTLY OVER
NORTHERN MEXICO TO BEGIN LIFTING EASTWARD BY THE MIDDLE OF THE
WEEK. HOWEVER, THE 00Z RUN OF THE ECMWF SHOWS THIS LOW SHIFTING
NEARLY DUE EAST AND ACROSS NORTH FLORIDA BY FRIDAY AND SATURDAY
WHICH WOULD TEND TO DESTABILIZE SOUTH FLORIDA ONCE AGAIN WHILE THE
LAST FEW RUNS OF THE GFS HAVE SHOWN THE LOW LIFTING MORE TO THE
NORTHEAST WELL NORTH OF THE PENINSULA. THE 12Z RUN HAS SHIFTED A
TAD FARTHER TO THE SOUTH BUT WILL WAIT FOR MORE CONSISTENT RUNS
BEFORE ADJUSTING THE FORECAST KEEPING IT DRY FOR NOW INTO NEXT
WEEKEND.

MARINE...
TRANQUIL WIND AND SEAS WILL CONTINUE THROUGH THE
WEEKEND OUTSIDE OF ISOLATED STRONG CONVECTION. A COLD FRONT WILL
MOVE ACROSS THE SOUTH FLORIDA WATERS LATE MONDAY WITH STRONG HIGH
PRESSURE BUILDING BEHIND THE FRONT WITH INCREASING WIND AND SEAS
MONDAY NIGHT INTO MID WEEK.

FIRE WEATHER...
NO PROBLEMS OR CONCERNS WITH AMPLE TROPICAL MOISTURE THROUGH MONDAY.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  74  86  73  85 / 60 50 30 30
FORT LAUDERDALE  77  86  74  85 / 40 50 20 50
MIAMI            76  87  75  87 / 40 40 20 50
NAPLES           73  87  73  85 / 10 20 20 20

&&

.MFL WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
AM...NONE.
GM...NONE.
&&

$$

DISCUSSION/MARINE/FIRE...13/SI
AVIATION/RADAR...85/AG