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000
FXUS62 KKEY 240238
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
1038 PM EDT TUE SEP 23 2014

.DISCUSSION...
.CURRENTLY...
AFTER WAITING ALL EVENING FOR A WORKED OVER ATMOSPHERE TO INITIATE
AGAIN WITH SHOWERS AND THUNDERSTORMS...THE LAST FEW VOLUME SCANS HAVE
SHOWED INTENSIFYING SHOWERS AND A FEW THUNDERSTORMS ACROSS THE LOWER
KEYS...AND EXTENDING WESTWARD...AS WELL AS SOUTH OF THE UPPER KEYS.
MOTION OF ALL SHOWER AND STORMS ARE TO THE NORTH-NORTHWEST AT 10 TO
15 KNOTS. REGIONAL NIGHTTIME SATELLITE PRESENTATION SHOWS A
CONVOLUTED PATTERN. BUT THE TWO MOST NOTABLE FEATURES ARE A DEEP
CONVERGENCE BOUNDARY THAT STRETCHES FROM THE CAROLINAS SOUTHWEST
ACROSS CENTRAL FLORIDA...AND INTO THE YUCATAN CHANNEL. THE OTHER
FEATURE IS A BROAD TROPICAL WAVE THAT IS CURRENTLY CENTERED ACROSS
EASTERN CUBA AND THE SOUTHERN BAHAMAS. CLOSER TO HOME...WINDS IN ALL
MARINE LOCATIONS HAVE BEEN NEAR 10 KNOTS THIS EVENING OUTSIDE OF
SHOWER ACTIVITY. TEMPERATURES ARE NEAR SEASONAL VALUES OUTSIDE OF
SHOWER ACTIVITY...AND IN THE UPPER 70S INSIDE OF AREAS IMPACTED BY
SHOWERS. EVENING SOUNDING CONTINUED THE MOIST AND UNSTABLE
PATTERN...AND HINTED AT THE MOST SUBTLE OF VEERING PROFILES. SLIGHT
AMOUNTS OF REDUCED INSTABILITY ARE INTERPOLATED FROM MODEST COOLING
NEAR THE SURFACE AND MODEST WARMING NEAR 500 MB FROM 24 HOURS AGO.

.SHORT TERM...
VERY FEW CHANGES ARE WARRANTED IN EITHER TEXT OR GRIDDED FORECASTS
FOR THE OVERNIGHT TIME PERIOD. THE LOW LEVEL TROPICAL WAVE IS QUICKLY
APPROACHING THE OUTER FLORIDA STRAITS SOUTH AND WEST OF THE
BAHAMAS...AND AN ANTICIPATED SURGE IN WINDS IS EXPECTED TO BE
ACCOMPANIED BY THIS WAVE. MODELS HAVE BEEN FRAUGHT WITH CONVECTIVE
FEEDBACK FOR THE PAST TWO DAYS MAKING IT DIFFICULT TO PLACE ANY
CONFIDENCE IN MESOSCALE INTERPOLATED FEATURES. MODEL SOUNDINGS
OVERNIGHT HOWEVER KEEP THE ISENTROPIC VEERING PROFILE AS A NOTABLE
FEATURE. THIS COMBINED WITH A STILL DEEPLY MOIST AND UNSTABLE
ENVIRONMENT...AND AN ACCOMPANYING WIND SURGE MORE THAN JUSTIFIES HIGH
END CHANCE POPS ACROSS THE REGION. CURRENT LIGHTNING TRENDS...AND
GRADUAL STABILIZATION OF THE EVENING SOUNDING BOTH SUPPORTED A CHANGE
TO ISOLATED THUNDER RATHER THAN EARLIER SCATTERED CHANCES. ALL OTHER
FORECAST VALUES LOOK WELL ON TRACK AT THIS TIME.

&&

.MARINE...
A RATHER ABRUPT SURGE IN WINDS IS EXPECTED TO ARRIVE SHORTLY AFTER
MIDNIGHT TONIGHT...BOTH INCREASING GRADIENT WINDS ACROSS THE REGION
AND ALSO ENCOURAGING INCREASED SHOWER ACTIVITY DUE TO INCREASED
BOUNDARY LAYER TURBULENCE. HAVE OPTED TO NOT INCLUDE "WINDS AND SEAS
HIGHER" WORDING AROUND THESE THUNDERSTORMS AS MIDLEVEL FLOW STILL
REMAINS RATHER TEPID...BUT AN ISOLATED CELL OR TWO MAY STILL CONTAIN
GUSTY WINDS. NO CHANGES REQUIRED BEYOND THE FIRST PERIOD.

&&

.AVIATION...OVERNIGHT AND WEDNESDAY...VFR CONDITIONS WILL PREVAIL AT
BOTH THE KEY WEST AND MARATHON ISLAND TERMINALS. SHOWERS ARE
UPSTREAM OF THE EYW TERMINAL SO THERE IS AN AMEND IN PLACE. A
WESTWARD LOW LEVEL IMPULSE WILL ALLOW FOR BRIEF MVFR/IFR CIGS AT
BOTH TERMINALS THROUGH TOMORROW. ADDITIONAL AMENDMENTS WILL BE
ISSUED AS NECESSARY. SURFACE WINDS WILL AVERAGE FROM 070-100 DEGREES
AOA 8 TO 10 KNOTS THRU 14Z...INCREASING TO 12 KNOTS AND GUSTY
THEREAFTER...EXCEPT GUSTS TO BETWEEN 20 AND 25 KNOTS IN STRONGER
SHOWERS.


&&

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

$$

PUBLIC/MARINE.........MSB
AVIATION/NOWCASTS.....FUTTERMAN
DATA COLLECTION.......VICKERY

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