Area Forecast Discussion
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FXUS62 KKEY 181845
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
245 PM EDT THU SEP 18 2014

.DISCUSSION...
.CURRENTLY...
SCATTERED SHOWERS WITH A FEW THUNDERSTORMS ARE MOVING TO THE EAST
ACROSS THE GULF AND BAY WATERS NORTH OF THE ISLAND CHAIN AT THIS
HOUR. WINDS OUTSIDE OF THESE SHOWERS ARE LIGHT AND OUT OF THE WEST.
PLENTY OF CLOUD COVER HAS REDUCED HEATING THUS FAR TODAY. THE
CLOUDINESS IS FROM A VERY WEAK TROUGH LINGERING NORTH OF THE KEYS.
VERY WEAK LOW LEVEL CONFLUENCE IS THE CULPRIT FOR THE DEVELOPING
SHOWERS.

.FORECAST...
THE EXISTING FORECAST IS HANDLING THE SCENARIO WELL THUS FAR SO THERE
WILL BE ONLY NUANCE CHANGES TO THIS ITERATION. THE EXPECTATION IS FOR
THE COPSE OF SHOWERS TO THE NORTH TO EXPAND OVERNIGHT DUE TO THE HIGH
MOISTURE CONTENT IN THE COLUMN AND SLIGHTLY BETTER LIFTING FOR THE
REST OF THE AFTERNOON AND OVERNIGHT. CONFLUENCE IN THE LOW
LEVELS...OUTFLOW BOUNDARIES...AND BETTER UP-GLIDE ACROSS THE ISENTROPES
ARE SEVERAL OF THE MECHANISMS FOR THE MODERATE TO HIGH CHANCE POPS.
THE TROUGH WILL SLOWLY LIFT OUT BEGINNING FRIDAY...WITH THE ENSEMBLE
MEMBERS SHOWING A WEAK SURFACE FEATURE MOVING NORTHEAST OFF THE EAST
COAST OF NORTH FLORIDA. THE SOUTHERN EXTENT OF THE MID TO UPPER
LEVEL TROUGH WILL REMAIN NEAR THE AREA...WITH ADDITIONAL TROPICAL
MOISTURE LIFTING THROUGH THE CONFLUENT ZONE. THIS WILL KEEP THE
THREAT FOR SHOWERS AND THUNDERSTORMS ABOVE CLIMATOLOGY THROUGH SUNDAY
NIGHT. THE WIND FORECAST IS STATUS QUO WITH LIGHT WINDS THROUGH
MONDAY....SHIFTING TO THE EAST TO SOUTHEAST SUNDAY WITH A LOW LEVEL
RIDGE SLIDES NORTH OF THE AREA. THE RIDGE WILL STRENGTHEN TUESDAY
LATE THROUGH WEDNESDAY INCREASING EAST WINDS AND PROVIDING A BETTER
CHANCE FOR SHOWERS AND THUNDERSTORMS TUESDAY NIGHT THROUGH WEDNESDAY.

&&

.MARINE...
WEAKNESS IN THE PRESSURE FIELD WILL CONTINUE THROUGH AT LEAST
SATURDAY RESULTING IN LIGHT WINDS WITH A FOCUS FROM THE
WEST...SOUTH TO SOUTHWEST TO NORTHWEST TO NORTH. A RIDGE WILL BUILD
IN NORTH OF THE AREA LATE IN THE WEEKEND SHIFTING WINDS BACK TO AN
EAST TO SOUTHEAST DIRECTION.

&&

.AVIATION...
UNTIL 12Z/19TH...OUTSIDE OF AN EPISODE OR TWO OF SUB-VFR
CONDITIONS...VFR CONDITIONS WILL PREVAIL AT THE KEY WEST AND
MARATHON TERMINALS. AWAY FROM SHOWERS...THUNDERSTORMS OR OUTFLOW
BOUNDARIES...MOSTLY WEST WINDS OF LESS THAN 10 KNOTS ARE EXPECTED.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...1926...THE GREAT MIAMI
HURRICANE MADE LANDFALL ON MIAMI BEACH EARLY MORNING SEPTEMBER 18TH.
MAXIMUM SUSTAINED WINDS IN MIAMI WERE REPORTED AROUND 145 MPH WITH A
MINIMUM CENTRAL PRESSURE OF 930 MB OR 27.46 INCHES OF MERCURY. IN KEY
WEST THE PEAK WIND WAS 52 MPH WITH A MINIMUM PRESSURE 998 MB OR
29.48 INCHES OF MERCURY.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  78  87  79  87 / 40 40 50 50
MARATHON  78  88  79  88 / 40 40 50 50

&&

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

$$

PUBLIC/MARINE.........BWC
AVIATION/NOWCASTS.....APA
DATA COLLECTION.......VICKERY

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