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000
FXUS62 KKEY 252003
AFDKEY

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
403 PM EDT SAT MAY 25 2013

.DISCUSSION...
LATEST DOPPLER RADAR TRENDS SHOW AN ISOLATED CLUSTER OF SHOWERS AND
THUNDERSTORMS MOVING WESTWARD OFF EAST CAPE SABLE. ISOLATED
CONVECTIVE CELLS HAVE BEEN ABLE TO DEVELOP TODAY AGAIN WHERE
SUFFICIENT SURFACE CONVERGENCE HAS BEEN AVAILABLE...DESPITE SOME VERY
DRY AIR ALOFT...INCLUDING AT LOW ALTITUDES. IT SEEMS WEAKER
ENVIRONMENTAL SHEAR COMBINED WITH A SLIGHTLY CONFLUENT FLOW PATTERN
ON THE SYNOPTIC SCALE MAY BE ALLOWING THE CELLS TO DEVELOP AS SIMILAR
THERMODYNAMIC CONDITIONS ON DAYS WITH SLIGHTLY DIFFERENT SYNOPTIC
SETUPS RESULT IN COMPLETE SUPPRESSION OF CONVECTIVE ACTIVITY.
ANYWAY...SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL PERSIST
OVER PORTIONS OF THE GULF ZONES THIS EVENING...BEFORE DISSIPATING
LATE TONIGHT...WITH ONLY SLIGHT SHOWER CHANCES IN FLORIDA KEYS ISLAND
COMMUNITIES.

THE FORECAST FOR THE COMING WEEK WILL FEATURE A GENERALLY BREEZY
EASTERLY FLOW THROUGHOUT AS A LARGE HIGH PRESSURE CELL VACILLATES IN
BOTH POSITION AND INTENSITY NORTH OF THE KEYS. WE ARE FAIRLY CERTAIN
THAT EVEN DRIER AIR UPSTREAM WILL FILTER INTO THE REGION LATER
TONIGHT AND SUNDAY...THEREBY LARGELY SHUTTING DOWN DEEP...MOIST
CONVECTION AND KEEPING MEASURABLE RAIN CHANCES VERY LOW. A LARGE-
SCALE TROUGH IN THE WESTERLIES WILL APPROACH EARLY IN THE WEEK
RESULTING IN BOTH GEOPOTENTIAL HEIGHT FALLS/WEAK ASCENT OVER THE
FLORIDA PENINSULA DURING THE MONDAY NIGHT-THURSDAY TIME FRAME AS WELL
AS A SLIGHTLY MORE EAST-SOUTHEAST FLOW AT LOW LEVELS RESULTING IN
DEEPER CARIBBEAN MOISTURE ADVECTING IN. THE COMBINATION OF THESE
FACTORS SHOULD PRODUCE MORE CLOUDS AND PRECIPITATION WITH MESOSCALE
FEATURES GOVERNING DAILY PATTERNS. THEREFORE...WE HAVE INCREASED RAIN
CHANCES FOR THE MID-WEEK TIME FRAME.
&&

.MARINE...
SMALL CRAFT ADVISORIES ARE BEING POSTED FOR ALL ZONES DUE TO
INCREASING WINDS AND SEAS TONIGHT. WIND AND/OR WAVE CONDITIONS WILL
FLIRT WITH ADVISORY CRITERIA FOR MUCH OF THE WEEK. SHOWER AND STORM
CHANCES WILL INCREASE MID WEEK.
&&

.AVIATION...
THROUGH THIS EVENING...VFR CONDITIONS ARE EXPECTED TO PREVAIL AT
BOTH THE KEY WEST AND MARATHON TERMINALS. ISOLATED SHOWERS ARE
POSSIBLE IN THE LOWER KEYS LATE THIS AFTERNOON AND EARLY
EVENING...WHICH INCLUDES THE KEY WEST TERMINAL. THEREFORE...BRIEF
MVFR CONDITIONS MAY BE POSSIBLE AT THE KEY WEST TERMINAL FROM
PASSING SHOWERS DURING THESE HOURS. HOWEVER... NO RESTRICTIONS TO
VISIBILITY WILL BE INCLUDING IN THE TERMINAL FORECAST BECAUSE OF LOW
CONFIDENCE IN SHOWERS REACHING KEY WEST...AS WELL AS UNCERTAINTY IN
THE TIMING OF THE SHOWERS. WILL AMEND TAF IF NECESSARY. SURFACE
WINDS AT BOTH TERMINALS WILL BE GENERALLY EAST NEAR 10 KNOTS WITH
GUSTS OF 15 TO 20 KNOTS.
&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  78  87  78  87 / 10 10 20 20
MARATHON  78  90  78  90 / 10 10 20 20
&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY IN EFFECT FOR GMZ031-GMZ032-GMZ033-GMZ034-
     GMZ042-GMZ043-GMZ044-GMZ052-GMZ053-GMZ054-GMZ055-GMZ072-GMZ073-
     GMZ074-GMZ075.
&&

$$

PUBLIC/MARINE.........KASPER
AVIATION/NOWCASTS.....DEVANAS
DATA COLLECTION.......BWC

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