Area Forecast Discussion
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000
FXUS62 KKEY 220636
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
236 AM EDT FRI AUG 22 2014

.DISCUSSION...
.CURRENTLY...
THE ISLANDS AND COASTAL WATERS ARE ON THE SOUTHERN PERIPHERY OF
RIDGING OVER THE GULF AND WESTERN ATLANTIC AS EASTERLY WINDS CAN
BE FOUND THROUGHOUT THE DEPTH OF OUR EVENING SOUNDING. THERE IS A
WEAKNESS OFF THE SOUTHEAST COAST AND OVER THE BAHAMAS BETWEEN HIGH
PRESSURE SITTING OVER THE SOUTHEAST AND THE WESTERN ATLANTIC
RIDGE...WHICH IS THE LIKELY PATH OF AL96 ACCORDING TO LATEST MODEL
GUIDANCE. THE EVENING SOUNDING FOUND PWV IN EXCESS OF TWO
INCHES...AND THE GSD GPS PWV SHOW THAT MOISTURE IS STILL IN THAT
NEIGHBORHOOD. KEY WEST RADAR IS DETECTING ISOLATED TO SCATTERED
SHOWER AND THUNDERSTORM COVERAGE IN THE STRAITS WITH SOME
POSSIBILITY THIS COULD MAKE IT TO THE MIDDLE KEYS IN THE NEXT FEW
HOURS.

.SHORT TERM...
TODAY THROUGH FRIDAY...GUIDANCE HAS BEEN CONSISTENT THE PAST FEW
RUNS SHOWING DRYING AND SUBSIDENCE THROUGH A FAIRLY DEEP LAYER
WHICH SHOULD SERVE TO INHIBIT CONVECTION.

SATURDAY AND SUNDAY...THE DRIER AIR THROUGH THE BOUNDARY LAYER
SHOULD PERSIST AS WE WILL BE IN THE WESTERN SUBSIDENCE REGION OF
AL96. HOWEVER...MUCH DEPENDS ON WHETHER MAINLAND CONVECTION FIRES
SINCE OUR FLOW WILL BE GENERALLY NORTHEASTERLY THROUGH A DEEP
LAYER. THIS COULD RESULT IN LAND BREEZE OR OUTFLOW BOUNDARIES
TRIGGERING CONVECTION THAT COULD REACH THE ISLANDS AND COASTAL
WATERS. THE SLIGHT CHANCE POPS FOR THE FORECAST PERIOD ASSUMES
CONVECTION ON THE MAINLAND WILL STRUGGLE.

&&

.LONG TERM...
MONDAY THROUGH THURSDAY...AS THE TROPICAL SYSTEM PULLS OFF TO THE
NORTH THE MOISTURE PROFILE SHOULD RETURN TO A MORE NORMAL STATE
AND THE SUBSIDENCE WILL WANE. WITH THE DISTURBANCE MOVING OFF TO
THE NORTH THE AREA WILL BE IN A GENERAL COL BETWEEN TROUGHING TO
THE EAST AND RIDGING OVER THE SOUTHEASTERN STATES. BECAUSE OF
THIS...BOUNDARY LAYER FLOW WILL BE RELATIVELY LIGHT...WHICH SHOULD
FAVOR CLOUD LINES AND MESOSCALE INTERACTIONS. WILL BRING POPS BACK
UP TO CLIMATOLOGY FOR THIS PERIOD.

&&

.MARINE...
GENTLE TO MODERATE EASTERLY BREEZES SHOULD PERSIST THROUGH FRIDAY
ON ALL KEYS COASTAL WATERS. ISOLATED SHOWERS AND THUNDERSTORMS ARE
POSSIBLE THROUGH THE MORNING HOURS FOLLOWING SUNRISE...BUT SHOULD
DECREASE IN COVERAGE THROUGH THE AFTERNOON. ON SATURDAY AND SUNDAY
EXPECT NORTHEASTERLY GENTLE TO MODERATE BREEZES...AND ONLY A FEW
SHOWERS AND THUNDERSTORMS.

&&

.AVIATION...
HAVE A SHORT PERIOD OF MVFR CONDITIONS TEMPOED AT THE MARATHON
AIRPORT EARLY THIS MORNING DUE TO THE SMALL SHOWERS UPSTREAM.
OTHERWISE...THE PROBABILITY OF SUB-VFR CONDITIONS AT EITHER MARATHON
OR KEY WEST IS LOW ENOUGH TO KEEP OUT OF THE REMAINDER OF THE
FORECAST PERIOD. EXPECT EASTERLY BREEZES AVERAGING 10 KNOT OR LOWER
AT BOTH LOCATIONS.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1975...1.61 INCHES OF RAIN
WAS RECORDED IN KEY WEST. THIS SET THE DAILY RAINFALL RECORD FOR
AUGUST 22 IN KEY WEST. RAINFALL RECORDS FOR KEY WEST DATE BACK TO
1872.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  92  83  92  83 / 20 20 20 20
MARATHON  94  83  94  83 / 20 20 20 20

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...NONE.
&&

$$

PUBLIC/MARINE.........DEVANAS
AVIATION/NOWCASTS.....11

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