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000
FXUS62 KMFL 111357
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
957 AM EDT SAT MAY 11 2013

.UPDATE...
CHANGES ARE NOT BEING PLANNED FOR THE MORNING UPDATES AT THIS
TIME. CONVECTIVE PARAMETERS LOOK SIMILAR TO YESTERDAY WITH SOME
MINOR FLUCTUATIONS. A MID LAYER INVERSION REMAINS ALTHOUGH IT IS
AT A LOWER LEVEL AROUND 700 MB VERSUS 500 MB FROM YESTERDAY
MORNING. STILL, THE LOW LEVELS REMAIN QUITE UNSTABLE SO THIS WOULD
SUGGEST THAT DEEP CONVECTION WILL ONCE AGAIN BE DELAYED. THIS ALSO
IS WHAT THE HRRR IS DEPICTING WITH STRONG CONVECTIVE ACTIVITY
DEVELOPING AROUND THE 20-21Z TIME FRAME. STORM MOTION WILL AGAIN
BE VERY SLOW WITH A DRIFT TOWARDS THE EAST. THE MAX CAPE TODAY IS
A LITTLE LOWER AT LESS THAN 2000 J/KG BUT THE 500 MB TEMPERATURE
COOLED BY 1 DEGREE CELSIUS WHICH OFFSETS THE INSTABILITY. SO ALL
THINGS CONSIDERED, FORECAST WILL REMAIN UNCHANGED.

KOB

&&

.PREV DISCUSSION... /ISSUED 818 AM EDT SAT MAY 11 2013/

AVIATION...
GENERALLY...VFR CONDITIONS WILL PREVAIL THROUGH THE WEEKEND. MOSTLY
CLEAR SKIES AND CALM WINDS EARLY THIS MORNING WILL GIVE WAY TO
INCREASING CUMULUS AND SOUTHEAST WINDS AT 10-15 KTS.  SCATTERED
SHOWERS AND THUNDERSTORMS ARE EXPECTED TO DEVELOP THIS AFTERNOON AND
PERSIST THROUGH EARLY EVENING. CURRENT CONFIDENCE IN TIMING/LOCATION
OF CONVECTION IS NOT HIGH...SO HAVE ONLY PLACED VCSH IN TAFS FOR 12Z
ISSUANCE. BEST CHANCE OF THUNDERSTORMS IS KPBI AND RISK OF SHOWERS
ARE LOWEST IN KAPF...WHERE POP BELOW 20 PERCENT DIDNT WARRANT
MENTION IN TAF.  ANY THUNDERSTORMS COULD HAVE GUSTY WINDS AND
SIGNIFICANT BUT BRIEF FLIGHT RESTRICTIONS. THIS EVENING...ACTIVITY
SHOULD DIMINISH AND A RETURN TO MOSTLY CLEAR SKIES AND LIGHT WINDS.

PREV DISCUSSION... /ISSUED 411 AM EDT SAT MAY 11 2013/

DISCUSSION...
WATER VAPOR AND NAM ANALYSIS FROM THIS MORNING SHOWED AN UPPER
RIDGE STRETCHING FROM THE SOUTHERN GULF AND WESTERN CARIBBEAN
NORTHEASTWARD OVER SOUTH FLORIDA INTO THE WESTERN ATLANTIC. AN
UPPER LEVEL TROUGH WAS DIGGING INTO THE PLAINS...AND A CUT OFF
UPPER LOW REMAINED OVER BAJA CALIFORNIA AND WESTERN MEXICO. AT THE
SURFACE...THE RIDGE REMAINED OVER THE WESTERN ATLANTIC...WITH THE
RIDGE AXIS OVER NORTH CENTRAL FLORIDA.

THE UPPER LEVEL RIDGE WILL SHIFT EAST AND FLATTEN OUT OVER SOUTH
FLORIDA TODAY AS THE UPPER LEVEL TROUGH DIGS INTO THE SOUTHEAST.
TEMPERATURES AT 500MB AND ABOVE WILL WARM TODAY...SO THE HAIL
THREAT WILL BE SLIGHTLY LOWER THAN ON FRIDAY. HOWEVER...0-6KM
SHEAR WILL INCREASE TO AROUND 30 KNOTS...WITH SOMEWHAT DRIER AIR
IN THE MID LEVELS. SO THE WIND THREAT MAY ACTUALLY BE
HIGHER...WITH STRONG TO ISOLATED SEVERE STORMS POSSIBLE. SPC HAS
ALSO ADDED THE EAST COAST IN 5 PERCENT WIND AND HAIL THREAT FOR
TODAY. THE FLOW AT 850MB AND ABOVE WILL BE LIGHT OUT OF THE WEST
TO NORTHWEST. SO STORMS WILL FORM CLOSER TO THE EAST COAST...AND
MOVE BACK TOWARDS THE EAST COAST THIS AFTERNOON. STORM MOTION WILL
BE SLOW...SO LOCALLY HEAVY RAINFALL IS POSSIBLE WHERE STORMS
DEVELOP. MODELS INDICATE DECENT AMOUNTS OF QPF...BUT POP GUIDANCE
IS 20-30 PERCENT. THE POP GUIDANCE HAS BEEN WAY TOO LOW THE PAST
SEVERAL DAYS...SO WENT ABOVE GUIDANCE THE NEXT SEVERAL DAYS...IN
THE 30-50 PERCENT RANGE ACROSS THE INTERIOR AND EAST.

AN MCS IS SUPPOSED TO DEVELOP ACROSS THE NORTH CENTRAL GULF THIS
AFTERNOON AND TRACK EAST INTO NORTHERN AND CENTRAL FLORIDA LATE
THIS AFTERNOON. MODELS DO NOT HANDLE THESE FEATURES ALL THAT
WELL...SO IT IS POSSIBLE THE TAIL END OF THE SHOWERS AND STORMS
COULD MOVE INTO THE OFFSHORE GULF WATERS LATE THIS AFTERNOON INTO
THE EVENING...SO HAVE SLIGHT CHANCE POPS FOR THIS POSSIBILITY.
SHOWERS AND THUNDERSTORMS ACROSS THE EASTERN HALF OF THE AREA WILL
WIND DOWN THIS EVENING WITH THE LOSS OF DAYTIME HEATING. TEMPS
WILL BE WARM TODAY AND TONIGHT...WITH HIGHS IN THE MID 80S TO
LOWER 90S AND LOWS IN THE MID 60S TO MID 70S.

A COLD FRONT WILL MOVE INTO NORTHERN FLORIDA ON SUNDAY. FLOW ALOFT
WILL BE LIGHT OUT OF THE WEST...SO STORMS WILL CONCENTRATE ACROSS
THE INTERIOR AND TOWARDS THE EAST COAST. TEMPS ALOFT WILL WARM
SLIGHTLY...AND SHEAR WILL BE LESS...BUT THERE COULD BE SOME STRONG
STORMS. TEMPS WILL REMAIN SIMILAR TO SATURDAY.

THE UPPER LEVEL TROUGH WILL DIG DOWN INTO THE FLORIDA PENINSULA ON
MONDAY...AND THE FRONT WILL ALSO MOVE INTO SOUTH FLORIDA. THE
REGION WILL ALSO BE IN THE RIGHT ENTRANCE REGION OF 90-100KT JET
STREAK. THE GFS IS INDICATING 30 KT 0-6KM BULK SHEAR IN THE
AFTERNOON. HOWEVER...CAPE IS EXPECTED TO BE MUCH LOWER THAN THE
OVER THE WEEKEND. SO THE BEST CHANCE OF STORMS WILL BE ACROSS THE
NORTH AND NORTHEAST IN THE MORNING TO EARLY AFTERNOON...AND THEN
ACROSS THE SOUTHEAST AND ESPECIALLY MIAMI-DADE COUNTY IN THE
AFTERNOON.

COOLER AND MUCH DRIER AIR WILL THEN MOVE INTO THE REGION MONDAY
NIGHT AND TUESDAY...AND CONDITIONS WILL REMAIN MOSTLY DRY THROUGH
THE END OF THE WEEK. HIGH PRESSURE WILL BUILD INTO THE SOUTHEAST
AND WESTERN ATLANTIC TUESDAY...WITH INCREASING NORTHEASTERLY FLOW
OVER THE LOCAL WATERS. HIGH TEMPERATURES ARE EXPECTED TO ONLY BE
IN THE LOW TO MID 80S THROUGH THE END OF WEEK. LOW TEMPERATURES
WILL DROP OFF INTO THE 50S ACROSS THE INTERIOR EACH NIGHT...WITH
60S TO AROUND 70 DEGREES FOR THE METRO AREAS.

MARINE...
MOSTLY SOUTHEAST TO SOUTH WIND THROUGH THE WEEKEND AT LESS THAN 15
KNOTS WITH SEAS LESS THAN 3 FEET. HIGH PRESSURE BEGINS TO BUILD
NORTH OF THE REGION EARLY NEXT WEEK WITH WINDS AND SEAS BUILDING
BUT REMAINING BELOW ADVISORY CRITERIA.

FIRE WEATHER...
SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH AFTERNOON
THIS WEEKEND ACROSS THE INTERIOR AND TOWARDS THE EAST COAST.
MINIMUM RELATIVE HUMIDITY VALUES WILL REMAIN WELL ABOVE CRITICAL
VALUES EACH DAY THIS WEEKEND. DRIER AIR WILL BEGIN TO FILTER INTO
THE REGION MONDAY AFTERNOON...AND MINIMUM RELATIVE HUMIDITY VALUES
ARE EXPECTED TO BE NEAR 35 PERCENT ACROSS THE NORTHWEST INTERIOR
TUESDAY AFTERNOON.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  87  73  87  71 / 40 30 50 30
FORT LAUDERDALE  87  72  87  74 / 40 30 50 20
MIAMI            89  74  88  73 / 40 30 40 20
NAPLES           87  72  85  71 / 10 20 20 20

&&

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

$$