Area Forecast Discussion
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112
FXUS62 KKEY 110948
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
448 AM EST THU FEB 11 2016

.DISCUSSION...
CHANGES TO FORECAST -- VERY FEW CHANGES WERE MADE. RAIN CHANCES WERE
DROPPED FROM 10 TO 5 PERCENT TUESDAY NIGHT-WEDNESDAY NIGHT...AND A
FEW TWEAKS WERE MADE TO THE DIGITAL FORECAST DATABASE. GULF STREAM
INFORMATION WAS UPDATED IN THE COASTAL WATERS FORECAST SYNOPSIS.

CURRENT SITUATION/ANALYSIS -- A DEEP LONG WAVE TROUGH PERSISTS OVER
THE EASTERN UNITED STATES...WITH A TROUGH AXIS EXTENDING FROM EASTERN
CANADA SOUTHWESTWARD TO SOUTHERN MEXICO. A WIDESPREAD DRY AND STABLE
ARCTIC OR POLAR AIR MASS COVERS MOST OF THE CONTINENTAL UNITED STATES
AND ADJACENT COASTAL WATERS...INCLUDING THE FLORIDA KEYS WHERE AIR
TEMPERATURES CURRENTLY ARE IN THE 50S AND DEWPOINT TEMPERATURES ARE
45-50F. CLOUD COVER OVER THE KEYS HAS THINNED CONSIDERABLY DURING THE
LAST 10 HOURS. STRATOCUMULUS CEILINGS ARE GONE...AND ONLY SCATTERED
HIGHER CIRRUS REMAINS. LOCAL DOPPLER RADAR SCANS ARE VOID OF
PRECIPITATION ECHOES. LOCAL SEA SURFACE TEMPERATURES RANGE FROM 63F
AT LONG KEY IN FLORIDA BAY...TO 72F AT MOLASSES REEF OFF KEY LARGO.

PROGNOSTIC OVERVIEW -- FORECAST REASONING HAS NOT CHANGED TOO MUCH
DURING THE LAST 24 HOURS. THE LARGE-SCALE EASTERN U.S. TROUGH AND ITS
DEEP AND EXPANSIVE CYCLONIC FLOW FIELD WILL PERSIST FOR ANOTHER FEW
DAYS. AT THE SURFACE...A WEAK...LOW-LATITUDE HIGH PRESSURE CELL WILL
MIGRATE EASTWARD ACROSS THE GULF BASIN AND FLORIDA PENINSULA TODAY
THROUGH FRIDAY. MEANWHILE...A STRONG ARCTIC ANTICYCLONE WILL PLUNGE
EQUATORWARD FRIDAY NIGHT AND SATURDAY...BEFORE HEADING EASTWARD
THROUGH MONDAY. COOL...CLEAR...DRY...AND RAIN-FREE WEATHER WILL
PERSIST IN THE FLORIDA KEYS FROM TODAY THROUGH SATURDAY AS INCOMING
AIR TRAJECTORIES REMAINED ROOTED IN THE MODIFIED CONTINENTAL POLAR
AIR. HOWEVER...BY SUNDAY...VEERING LOW-LEVEL TRAJECTORIES OFF THE
WARMER SUBTROPICAL ATLANTIC WILL PROMOTE THE ONSET OF WEAK WARM
THERMAL AND MOISTURE ADVECTION AND ASSOCIATED LOWER-TROPOSPHERIC
LIFT...DESTABILIZATION...AND SLIGHT SHOWER CHANCES. SLIGHTLY HIGHER
RAIN CHANCES ARE FORECAST FOR MONDAY-TUESDAY AS WARM ADVECTION
PERHAPS INTENSIFIES SOMEWHAT IN ADVANCE OF A MIGRATING MIDLATITUDE
SHORT-WAVE TROUGH AND ASSOCIATED CYCLOGENESIS BETWEEN FROM THE GULF
COAST TO THE CAROLINAS. A FRONTAL PASSAGE IS PLAUSIBLE LOCALLY ON
TUESDAY OR TUESDAY NIGHT...BUT CONFIDENCE IN TIMING OR ASSOCIATED
WEATHER AND TEMPERATURE CHANGES IS LOW AT THIS STAGE...FIVE TO SIX
DAYS OUT.
&&

.MARINE...
NO MORE SMALL CRAFT ADVISORIES ARE IN EFFECT -- THEY WERE
DISCONTINUED WEDNESDAY EVENING. HOWEVER...SMALL CRAFT SHOULD EXERCISE
CAUTION FOR 15-20-KNOT WINDS IN THE STRAITS OF FLORIDA. SEAS OF 5-6
FEET DUE TO WEST SWELLS ARE EXPECTED IN THE LOWER STRAITS...SOUTH OF
THE REEF TRACT FROM THE SEVEN MILE BRIDGE WESTWARD PAST THE DRY
TORTUGAS.
&&

.AVIATION...
TODAY...VFR CONDITIONS WILL PREVAIL AT BOTH THE KEY WEST AND
MARATHON TERMINALS. WINDS WILL AVERAGE AROUND 9-12 KTS FROM 350-020
DEG. A FEW-SCT CLOUDS WILL BE FOUND AOA FL025-030 & FL040-050
RESPECTIVELY...WITH CIRRUS AOA FL200-250. SKIES WILL BECOME CLEAR
LATE IN THE DAY.
&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  65  60  72  62 / 0 0 0 0
MARATHON  65  60  72  60 / 0 0 0 0
&&

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

$$

PUBLIC/MARINE.........KASPER
AVIATION/NOWCASTS.....FUTTERMAN
DATA COLLECTION.......FUTTERMAN

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