486
FXUS62 KKEY 181940
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
330 PM EDT TUE JUN 18 2013

...LITTLE CHANCE FOR RAINFALL WEDNESDAY THROUGH THURSDAY NIGHT...

.DISCUSSION...
.CURRENTLY...
SKIES ARE PARTLY CLOUDY WITH TEMPERATURES HOVERING AROUND 90 DEGREES
ALONG THE ISLAND CHAIN. LOCAL RADARS ARE DETECTING CYCLICAL ISOLATED
SHOWERS AND THUNDERSTORMS SURROUNDING THE FLORIDA KEYS....WITH THE
MAJORITY AND STRONGEST ACTIVITY 5 TO 20 NM NORTH OF THE LOWER KEYS.
SURFACE WISE...A WESTERN ATLANTIC RIDGE IS HOLDING ACROSS SOUTH
CENTRAL FLORIDA...WITH SOUTHEAST WINDS OF AROUND 10 KNOTS WITH GUSTS
NEAR 15 KNOTS ALONG THE REEF.

.SHORT TERM (TONIGHT THROUGH FRIDAY)...
AN EAST-WEST ORIENTED...DEEP TROPOSPHERIC ANTICYCLONE ALIGNED ACROSS
THE SOUTHERN PORTION OF THE FLORIDA PENINSULA WILL HELP DRIVE A
SAHARAN AIR LAYER WESTWARD AND INTO OUR AREA LATE TONIGHT AND
ESPECIALLY WEDNESDAY THROUGH THURSDAY. THIS SEASONABLE SYNOPTIC
SCALE REGIME IS WELL DEPICTED BY FORECAST SOUNDINGS WHICH REVEAL
BELOW NORMAL MOISTURE (PWAT 1.30 INCHES OR LESS)...A STRENGTHENING
LOW LEVEL INVERSION BELOW 850 MB ALONG WITH A FAIRLY STEEP...NEARLY
ADIABATIC LAPSE RATE ABOVE. WITH THAT SAID...WILL MAINTAIN ONLY
ISOLATED POPS THROUGH THE PERIOD...BUT IT APPEARS THAT RAIN CHANCES
WILL LIKELY BE REMOVED THURSDAY AND THURSDAY NIGHT.
OTHERWISE...RESPLENDENT SUNSHINE...ALBEIT MILKY SKIES AT
TIMES...WILL ALLOW HIGH TEMPERATURES TO SOAR TO NEAR 90 DEGREES WITH
OVERNIGHT LOWS MAINLY IN THE LOWER 80S DUE TO MODERATE EAST WINDS
AND LITTLE IF ANY PRECIPITATION.

&&

.LONG TERM (FRIDAY NIGHT THROUGH TUESDAY)...
MEDIUM RANGE GUIDANCE CONTINUES TO INDICATE A LOW AND MID LEVEL
UNDULATION...ALBEIT IN VARY DEGREES OF INTENSITY OVER THE BAHAMAS
FRIDAY NIGHT MIGRATING WEST AND TRACKING ACROSS OUR REGION SATURDAY
AND SATURDAY NIGHT...BEFORE EMERGING INTO THE SOUTHEAST GULF OF
MEXICO SUNDAY. MEANWHILE...THE PERSISTENT AND CLIMATOLOGICAL FAVORED
DEEP LAYERED WESTERN ATLANTIC RIDGE WILL RELOCATE SLIGHTLY INTO
NORTH FLORIDA AND STRENGTHEN. WITH THIS IN MIND...THE UNCERTAINTY ON
THE LOW LEVEL VORTICITY AND MOISTURE CONTENT WILL PROMPT LOW CHANCE
POPS TO BE RETAINED THROUGH SUNDAY...WITH SOME DRIER AIR FILTERING
IN TO MAINTAIN ISOLATED 20 PERCENT POPS THEREAFTER. TEMPERATURE
WISE...AMPLE INTENSE INSOLATION WILL ALLOW TEMPERATURES TO CLIMB
NEAR 90 DEGREES WITH OVERNIGHT LOWS NEAR 80 AWAY FROM ANY
DOWNPOURS.

&&

.MARINE...
GENTLE TO MODERATE EAST TO SOUTHEAST WINDS WILL PREVAIL ON KEYS
COASTAL WATERS TONIGHT AND WEDNESDAY...BEFORE WINDS GRADUALLY
INCREASE ON THURSDAY AND ESPECIALLY THURSDAY EVENING WHEN MODERATE
TO FRESH EAST WINDS WITH THE HIGHEST EXPECTED BEYOND 20 NM SOUTH OF
THE ISLAND CHAIN. WITH THAT SAID...AN EXERCISE CAUTION HEADLINE MAY
BE REQUIRED FOR THE FLORIDA STRAITS LATE THURSDAY INTO FRIDAY.
THEREAFTER...GENTLE TO MODERATE EAST WINDS SHOULD PREDOMINATE THIS
WEEKEND...WITH NO HEADLINES OR ADVISORIES ANTICIPATED.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL THROUGH AT LEAST 18/06Z AT BOTH THE KEY
WEST INTERNATIONAL AND MARATHON ISLAND TERMINALS. DUE TO
SOUTHEASTERLY LOW LEVEL FLOW...AND MOISTURE TRAPPED IN THE LOWER
LEVELS...EXPECT A FEW SHOWERS TO DEVELOP IN CLOUD STREETS ORIENTED
SOUTHEAST TO NORTHWEST THROUGH 19/00Z. NO MENTION IN TAF DUE TO THE
DIFFICULTY IN TIMING OF THE ISOLATED VARIETY OF PULSING SHOWERS.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1972...2.67 INCHES OF RAIN
FELL IN KEY WEST. THIS SET THE DAILY RECORD FOR RAINFALL ON JUNE
18TH...WHICH STANDS 41 YEARS LATER.


&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  82  89  83  89 / 20 10 10 10
MARATHON  84  92  84  92 / 20 10 10 10
&&

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

$$

PUBLIC/MARINE.........APA
AVIATION/NOWCASTS.....BWC
DATA ACQUISITION......MP/LK

VISIT US ON THE WEB AT WWW.WEATHER.GOV/KEYWEST