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000
FXUS62 KKEY 021839
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
245 PM EDT THU JUL 2 2015

.DISCUSSION...IN THE MID AND UPPER LEVELS...(700-200 MB)...LATEST
AVAILABLE IR IMAGERY OVERLAID WITH MODEL STREAMLINE ANALYSIS AS OF
200 PM CONTINUES TO SHOW LOW AMPLITUDE LARGE SCALE TROUGHING ACROSS
THE EASTERN CONUS...AND LARGE SCALE RIDGING ACROSS THE WESTERN
CONUS...WITH THE CENTER OF THIS WARM CORE SYNOPTIC SCALE ANTICYCLONE
LOCATED NEAR THE 4 CORNERS REGION. ACROSS THE LOWER LATITUDES AND
CLOSER TO THE FLORIDA KEYS...THE AXIS OF AN UPPER TROUGH...AT 250 MB
IS POSITIONED FROM THE SOUTHEASTERN GULF OF MEXICO SOUTHWEST ACROSS
WESTERN CUBA INTO THE NORTHWEST CARIBBEAN SEA. AT 500 MB...WEAK
BROAD TROUGHING IS EVIDENT ACROSS SOUTHEAST GULF OF MEXICO. THE
LATEST UNIVERSITY OF WISCONSIN CIMMS SAL (SAHARAN AIR ANALYSIS)
IMAGERY SHOWS THE LEADING EDGE OF THE MOST CONCENTRATED DUST IS
ENCROACHING UPON THE SOUTHEAST BAHAMAS AND DOMINICAN REPUBLIC
LONGITUDE. CIMMS PWAT ANALYSIS SHOWS SLIGHTLY MORE MOISTURE IN THE
COLUMN ACROSS SOUTH FLORIDA AND THE KEYS ATTM.

AT THE SURFACE AND IN THE LOWER TO MID LEVELS...AS OF 200
PM...SURFACE TO 700 MB...A 1020 MB SURFACE RIDGE IS LOCATED FROM THE
EASTERN GULF OF MEXICO SOUTHEAST TO ACROSS SOUTH FLORIDA THENCE INTO
THE NORTHERN BAHAMAS. ACROSS THE TROPICS...WEAK...BROAD SURFACE
TROUGHING EXISTS ACROSS THE NORTHWEST CARIBBEAN SEA.

.CURRENTLY...AS OF 200 PM...SKIES ARE MOSTLY SUNNY.TEMPERATURES
ACROSS THE ISLANDS HAVE REACHED AROUND 90 DEGREES WITH DEWPOINTS IN
THE UPPER 80S ACROSS THE ISLANDS. RADAR DETECTS A BAND OF SHOWERS
AND ISOLATED THUNDERSTORMS ACROSS THE CENTRAL FLORIDA STRAITS. C-MAN
STATIONS ALONG THE REEF ARE REGISTERING EAST TO SOUTHEAST WINDS AT
10 KNOTS OR LESS...WITH LAPS SURFACE ANALYSIS SUGGESTING THAT WINDS
ARE 10 TO 15 KNOTS ACROSS THE OUTERMOST FLORIDA STRAITS.

.SHORT TERM...TONIGHT THRU FRIDAY NIGHT...AN NEARLY STATIONARY UPPER
LEVEL LOW IN COMBINATION WITH BROAD MIDDLE LEVEL TROUGHING WILL
LINGER ACROSS THE SOUTHEAST GULF OF MEXICO NORTH OF PINAR DEL RIO.
LATEST AVAILABLE MODEL FORECAST SOUNDINGS...12Z GFS AND 00Z ECMWF
ILLUSTRATE COLUMNAR PWAT(PRECIPITABLE WATER) REMAINS BETWEEN 1.75 TO
2.00 THROUGH THE PERIOD. 1020 MB SURFACE RIDGING WILL REMAIN ACROSS
THE PENINSULA...WITH WEAK LOW LEVEL TROUGHING ACROSS THE FLORIDA
STRAITS AND POINTS WESTWARD. WEAKER UPPER LEVEL DIFFLUENCE AND LOWER
LEVEL CONFLUENT FLOW WILL CONTRIBUTE TO LOW CHANCES FOR SHOWERS AND
STORMS TONIGHT...MIDDLE OF THE ROAD CHANCES ON FRIDAY AND LOW
CHANCES FRIDAY NIGHT. LESS EVIDENCE OF ANY OF THIS TROUGHING AND THE
UPPER SYSTEM TO THE SOUTHWEST SHOULD EXIST BY FRIDAY NIGHT. HIGH AND
LOW TEMPERATURES WILL CONTINUE TO BE A COUPLE DEGREES ABOVE
SEASONABLE AVERAGES.

.INDEPENDENCE DAY THROUGH NEXT WEEK...THE SAL (SAHARAN AIR LAYER)
ANALYSIS DETECTS THE DEEPER CONCENTRATION TIMED TO BE ABOUT 3
PERIODS UPSTREAM OF THE KEYS ATTM. A SURFACE RIDGE IS PROGGED TO
REMAIN NORTH OF THE KEYS ACROSS THE PENINSULA THRU THE PERIOD...BUT
GIVEN THE TYPICAL INSTABILITY REMAINING IN THE BOUNDARY LAYER...BUT
WILL MAINTAIN ISOLATED SHOWERS AND THUNDER THROUGH THE PERIOD...WITH
SLIGHTLY BELOW NORMAL RAIN AND THUNDER CHANCES...AT 20 PERCENT.
DAYTIME HIGH AND OVERNIGHT LOW TEMPERATURES WILL CONTINUE TO BE MORE
TYPICAL OF AUGUST THAN EARLY JULY. RUNNING NEAR IN IN EXCESS OF
90...AND PROBABLY ABOVE 80 EACH NIGHT.

&&

.MARINE...GENTLE TO MODERATE WINDS ACROSS KEYS WATERS TONIGHT
THROUGH FRIDAY NIGHT. A LITTLE MORE BREEZE SEEMS POSSIBLE IN
RESPONSE TO A NOCTURNAL SURGE SATURDAY MORNING AND LATE SATURDAY
NIGHT THROUGH THE MIDDLE OF NEXT WEEK...BUT THIS WOULD BE ONLY
ACROSS THE OUTER STRAITS WELL AWAY FROM THE INFLUENCE OF LAND
MASSES. GENTLE TO MODERATE BREEZES WILL PREVAIL...HENCE NO HEADLINES
OR ADVISORIES.

&&

.AVIATION... MOSTLY VFR CONDITIONS WILL PREVAIL AT BOTH THE KEY WEST
AND MARATHON INTERNATIONAL TERMINALS THROUGH 03/18Z. VERY BRIEF MVFR
CEILINGS...OR VISIBILITIES MAY OCCUR AS WEAK LOW TOPPED SHOWERS MOVE
NORTHWEST NEAR 15 KNOTS.

&&

.CLIMATE... ON THIS DATE IN KEYS WEATHER HISTORY...1935...4.12
INCHES OF RAIN FELL IN KEY WEST. THIS SET THE DAILY RECORD RAINFALL
FOR KEY WEST ON JUNE 2ND...WHICH STANDS 80 YEARS LATER. RAINFALL
RECORDS FOR KEY WEST DATE BACK TO 1871.
&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  81  89  81  89 / 30 40 30 20
MARATHON  82  91  81  91 / 30 40 30 20

&&

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

$$

PUBLIC/MARINE.........FUTTERMAN
AVIATION/NOWCASTS.....BWC
DATA COLLECTION.......VICKERY/FLING

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