Area Forecast Discussion
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000
FXUS62 KKEY 260907
AFDKEY

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KEY WEST FL
407 AM EST MON JAN 26 2015

.DISCUSSION...
DURING THE EARLY EVENING HOURS...WINDS COLLAPSED AS EXPECTED WHICH
ALLOWED RADIATIONAL COOLING WITH TEMPERATURES DROPPING INTO THE LOWER
50S AT BIG PINE KEY TO MID TO UPPER 50S IN SOME LOCATIONS IN THE
LOWER AND MIDDLE KEYS. SINCE THEN...WEST WINDS HAVE SLOWLY INCREASED
WHICH HAS ALLOWED TEMPERATURES TO SLOWLY CLIMB AT MOST LOCATIONS DURING
THE OVERNIGHT HOURS. CURRENTLY...SKIES ARE PARTLY CLOUDY WITH
TEMPERATURES RANGING FROM 52 DEGREES AT BIG PINE KEY TO THE LOWER AND
MID 60S AT MOST LOCATIONS. MEANWHILE...LOCAL RADARS ARE NOT DETECTING
ANY PRECIPITATION ECHOES IN OUR ENTIRE REGION. SURFACE WISE...A
LARGE...BUT SLOWLY CONSOLIDATING  AREA OF LOW PRESSURE (1004 MB) IS
CENTERED OVER THE KENTUCKY...NORTH CAROLINA AND SOUTH CAROLINA
REGION...WITH AN ATTENDENT COLD FRONT DRAPED SOUTHWARD INTO THE
SOUTHEAST GULF OF MEXICO. ACROSS OUR MARINE DISTRICT...WINDS ARE
MOSTLY WEST NEAR 15 KNOTS.

.SHORT TERM...(TODAY THROUGH WEDNESDAY NIGHT)...
SURFACE LOW PRESSURE IN THE EASTERN TENNESSE VALLEY WILL RACE SWIFTLY
EASTWARD AND INTENSIFY ALONG THE MID ATLANTIC COAST...PULLING AN
ASSOCIATED COLD FRONT THROUGH OUR ENTIRE REGION DURING THIS AFTERNOON.
THIS RAPID CYCLOGENESIS WILL BE IN RESPONSE TO A VIGOROUS MID AND
UPPER LEVEL SHORT WAVE TROUGH IN THE SOUTHEAST UNITED STATES LIFTING
NORTHEASTWARD...AS A JET STREAK IN THE UPPER GREAT PLAINS DIVES
SOUTHEASTWARD. WITH THAT SAID...FORECAST SOUNDINGS REVEAL INCREASING
MOISTURE UP TO 700 MB WITH A STRONG INVERSION LIFTING AND ERODING
THIS MORNING AND EARLY THIS AFTERNOON. THIS SEEMS REASONABLE WITH
SOME SCALE ASCENT DUE TO A LOBE OF DIFFERENTIAL VORTICITY AND A
ROBUST JET STREAK JUST TO OUR NORTH. WITH THIS IN MIND...LOW LEVEL
CONFLUENCE WITH THE AFOREMENTIONED FRONT SHOULD GENERATE A BROKEN AND
FAIRLY NARROW SWATH OF SHOWERS TO PUSH THROUGH THIS AFTERNOON.
OTHERWISE...A TIGHTENING AND CYCLONIC PRESSURE GRADIENT COMBINED
WITH LOW LEVEL COLD AIR ADVECTION WILL PROVIDE WINDY CONDITIONS THIS
AFTERNOON AND EARLY TONIGHT...BEFORE DECREASING INTO THE BREEZY
CATEGORY ON TUESDAY INTO WEDNESDAY. OTHERWISE...ANOTHER SUBTLE AND
EXTREMELY MOISTURE STARVED COLD FRONT WILL PASS THROUGH OUR AREA LATE
TUESDAY NIGHT AND EARLY WEDNESDAY...MAINTAINING BELOW NORMAL
TEMPERATURES. SO OUTSIDE OF A 30 PERCENT CHANCE OF A BRIEF SHOWER
TODAY...DRY AND BELOW NORMAL TEMPERATURES CAN BE EXPECTED BEGINNING
TONIGHT.

.LONG TERM...(THURSDAY THROUGH SUNDAY)...
A WESTERN ATLANTIC SURFACE RIDGE EXTENDING ACROSS THE SUNSHINE STATE
WILL SAG SOUTHWARD...AS A DECAYING COLD FRONT SETTLES DOWN THE
FLORIDA PENINSULA BEFORE BECOMING STATIONARY NEXT WEEKEND. GIVEN A
ZONAL MID AND UPPER LEVEL FLOW...SCANT MOISTURE AND BELOW NORMAL
TEMPERATURES WILL GRADUALLY INCREASE AS A PERSISTENT AND STRONG
INVERSION JUST ABOVE THE BOUNDARY LAYER SLOWLY ERODES AND LIFTS TO
NEAR 700 MB. WITH THAT SAID...WILL MAINTAIN ONLY NICKLE POPS IN THE
GRIDS THROUGH THE PERIOD FOR NOW. TEMPERATURES WILL FINALLY REACH
THE UPPER 70S ON SUNDAY...BUT UNTIL THEN...LOW TEMPERATURES WILL
AVERAGE BETWEEN 60 TO 65 WITH HIGH TEMPERATURES IN THE LOWER TO MID
70S ALONG WITH COMFORTABLE HUMIDITY VALUES.

&&

.MARINE...
WEST WINDS WILL FRESHEN QUICKLY THIS MORNING...BEFORE BECOMING STRONG
ESPECIALLY ON THE WATERS NORTH OF THE ISLAND CHAIN AND ADJACENT TO
THE UPPER KEYS. HENCE...A SMALL CRAFT ADVISORY IS IN EFFECT FOR OUR
ENTIRE MARINE DISTRICT. STRONG NORTHWEST WINDS EARLY TONIGHT WILL
SLOWLY ABATE OVERNIGHT...WITH MODERATE TO FRESH NORTHWEST WINDS ON
TUESDAY. WINDS WILL INCREASE AGAIN TUESDAY NIGHT INTO WEDNESDAY
MORNING WHEN A SMALL CRAFT ADVISORY/EXERCISE CAUTION HEADLINE WILL
LIKELY BE REQUIRED. THEREAFTER...WINDS WILL SLACKEN INTO THE GENTLE
TO MODERATE RANGE FOR THE BALANCE OF THIS WEEK.

&&

.AVIATION...
...26/09Z TAF AMENDMENTS...VFR IS EXPECTED TO PREVAIL THROUGH THE
PERIOD. WESTERLY WINDS WILL RAMP TO 20G30KT ALONG THE IMPENDING
FRONTAL PASSAGE...AND THERE IS A DEBATABLE CHANCE FOR THE OCCURRENCE
OF SHOWERS ALONG THE SWIFTLY PASSING BOUNDARY WHICH MAY CREATE A FEW
BRIEF MVFR CIGS. OUTSIDE OF SHOWER ACTIVITY... SKIES WILL BE CLOUDY
AT TIMES THROUGH THIS AFTERNOON...BUT CIGS SHOULD GENERALLY BE ABOVE
3KFT.

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY IN EFFECT FOR ALL KEYS COASTAL WATERS.
GM031>035-042>044-052>055-072>075.

&&

$$

PUBLIC/MARINE.........APA
AVIATION/NOWCASTS.....MSB

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