Area Forecast Discussion
Issued by NWS Miami, FL

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FXUS62 KMFL 251814
AFDMFL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIAMI FL
214 PM EDT FRI JUL 25 2014

.SHORT TERM (TONIGHT-SUNDAY NIGHT)...
DEEP LAYER RIDGE CURRENTLY STRETCHES ACROSS SOUTH FLORIDA INTO THE
ATLANTIC WITH ANOTHER STRONG RIDGE OVER THE SOUTHERN PLAINS.
SANDWICHED IN BETWEEN THESE TWO HIGHS IS A WEAK TROUGH AND THIS HAS
CAUSED SOME DESTABILIZATION TO THE AIRMASS ACROSS SOUTH FLORIDA THIS
MORNING. THIS WILL CREATE A MORE ACTIVE AFTERNOON FOR THUNDERSTORMS
THAN YESTERDAY BUT THE STEERING FLOW WILL KEEP MOST ACTIVITY INLAND
AWAY FROM THE COASTS. HOWEVER, STEERING FLOW IS NEARLY PARALLEL TO
THE COASTS SO SOME CONVECTION WILL FIRE UP JUST INLAND FROM THE
COASTS BEFORE THE SEA BREEZES PUSH THE ACTIVITY WELL INLAND. MUCH
DRIER AIR ALOFT IS CURRENTLY LOCATED ACROSS THE CENTRAL BAHAMAS, AND
IN THE CIRCULATION AROUND THE BASE OF THE RIDGE WILL BEGIN TO MOVE
INTO SOUTH FLORIDA ON SATURDAY AND ESPECIALLY ON SUNDAY. THE GFS IS
MUCH FASTER WITH THE LEADING EDGE OF THE DRIER AIR WITH THE NAM NOT
SHOWING IT TO REACH THE SOUTHEAST COASTAL AREA UNTIL LATE SATURDAY
AFTERNOON. STILL, THE FORECAST SOUNDINGS ARE SHOWING PWAT LOWERING
TO AROUND 1.5 INCHES DURING THE COURSE OF THE DAY AND THIS WILL
LIMIT THE OVERALL COVERAGE OF THUNDERSTORMS. THE ATMOSPHERE WILL
REMAIN VERY UNSTABLE HOWEVER WITH PLENTIFUL LOW LEVEL MOISTURE SO
SCATTERED STORMS OVER THE INTERIOR WILL STILL BE ANTICIPATED. THE
STEERING FLOW WILL BE MORE EASTERLY BUT AT 5 MPH OR LESS SO SOME
STORMS COULD AGAIN FORM JUST INLAND FROM THE COASTS BEFORE PUSHING
TO THE INTERIOR AREAS. THE MODELS ARE IN GOOD AGREEMENT THAT THE
DRIEST AIR WILL ARRIVE BY SUNDAY WITH FORECAST SOUNDINGS SHOWING
PWAT DOWN TO LESS THAN 1.2 INCHES SO ACTIVITY WILL BE MUCH LESS. THE
500MB TEMPERATURES ARE ALSO DEPICTED TO WARM BACK TO AROUND -5 TO -
6C WHICH ALSO WILL ACT TO LIMIT THUNDERSTORM DEVELOPMENT.

.LONG TERM (MONDAY-FRIDAY)...
A STRONG AND DEEP MID/UPPER LEVEL TROUGH WILL DEVELOP ACROSS THE
EASTERN U.S. NEXT WEEK WITH A COLD FRONTAL BOUNDARY ENTERING NORTH
FLORIDA BY TUESDAY OR WEDNESDAY. THIS SET UP WILL LIKELY DESTABILIZE
THE AIRMASS OVER SOUTH FLORIDA ONCE AGAIN ALTHOUGH NEITHER THE GFS
NOR ECMWF SHOW SIGNIFICANT COOLING ALOFT AT THIS TIME AND NEITHER
INCREASE MOISTURE SUBSTANTIALLY. SO IT REMAINS UNCERTAIN AT THIS
TIME JUST HOW MUCH INFLUENCE THIS SYSTEM WILL HAVE ON SOUTH FLORIDA
BUT THE STEERING FLOW WILL TURN MORE SOUTH TO SOUTHWEST WITH THE
INTERIOR AND EAST COAST HAVING THE BETTER CHANCES FOR THE
THUNDERSTORMS.

ON A SIDE NOTE, THERE IS A SAHARAN DUST LAYER (SAL) ACROSS THE
CARIBBEAN AND THE CENTRAL ATLANTIC. THE MODELS KEEP MOST OF THIS TO
OUR SOUTH AND EAST BUT ARE SHOWING A DIFFUSE PART OF IT REACHING
SOUTHEAST TIP OF THE PENINSULA LATE THIS WEEKEND OR EARLY NEXT WEEK.
NO MAJOR EFFECTS ARE EXPECTED ALTHOUGH IT COULD MAKE THE SKY APPEAR
HAZIER THAN NORMAL.

&&

.AVIATION...
ALTHOUGH SHOWER AND STORM DEVELOPMENT HAS REMAINED LIMITED...THE FEW
THAT HAVE FORMED HAVE BEEN RIGHT NEAR THE EAST COAST TAF SITES. IT
IS POSSIBLE THAT NO OTHER SHOWERS OR STORMS FORM NEAR THE TAF SITES
THIS AFTERNOON...BUT KEPT VCTS THROUGH 22Z. SOUTHEAST WINDS 5-10
KNOTS ARE FORECAST THROUGH THE AFTERNOON AT THE EAST COAST TAF
SITES...WITH A WEST SOUTHWEST FLOW AT KAPF. DRIER AIR IS FORECAST BY
ALL THE MODELS TO BEGIN MOVING TOWARDS SOUTH FLORIDA ON SATURDAY.
HOWEVER...A FEW SHOWERS OR STORMS COULD FORM NEAR THE END OF THE TAF
PERIOD ALONG THE EAST COAST SEA BREEZE BEFORE THE DRIER AIR PUNCHES
FULLY INTO SOUTH FLORIDA.

&&

.MARINE...
TRANQUIL MARINE CONDITIONS WILL CONTINUE WITH A LIGHT EAST TO
SOUTHEAST WIND LESS THAN 15 KNOTS AND SEAS OF 2 FEET OR LESS.

&&

.PRELIMINARY POINT TEMPS/POPS...
WEST PALM BEACH  77  89  78  90 /  30  40  20  20
FORT LAUDERDALE  80  91  80  91 /  20  30  10  20
MIAMI            80  90  80  91 /  20  30  10  20
NAPLES           76  91  77  90 /  20  30  20  20

&&

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

$$

SHORT TERM...84/AK
LONG TERM....30/KOB
AVIATION...84/AK


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