Coastal Flood Statement 5, NWS Key West, FL

AREA FORECAST DISCUSSION FOR THE FLORIDA KEYS
NATIONAL WEATHER SERVICE KEY WEST FL
303 PM EDT THU OCT 7 2010

.DISCUSSION...
.CURRENTLY...
NOTHING TO DISCUSS FROM THE KBYX RADAR THIS AFTERNOON. AN AREA OF
ALTOCU EXTENDS ALONG THE FLORIDA EAST COAST...EAST OF THE UPPER KEYS
AND ACROSS CENTRAL CUBA. THE WESTWARD PROGRESS OF THE CLOUD COVER HAS
BEEN DUPED BY THE MID AND UPPER LEVEL WESTERLY FLOW ALOFT. WITH CLEAR
SKIES AND NORTHEAST WINDS NEAR THE SURFACE THE AIR MASS HAS REMAINED
DRY THIS AFTERNOON. THE GEIGER KEY INTEGRATED PWAT INDICATES AROUND
0.6 INCHES WITH 1.05 INCHES FROM THE MORNING SOUNDING DATA MAKES IT
VERY DRY AND COMFORTABLE FOR EARLY OCTOBER. ON THE LARGER SCALE
TROPICAL STORM OTTO IS EAST OF THE BAHAMAS WITH AN UPPER LEVEL LOW
OVER THE CANADIAN MARITIMES AND A TROUGH EXTENDING FROM CANADA
SOUTHWARD ACROSS CUBA INTO THE CARIBBEAN SEAS BETWEEN. AN ADDED
FEATURE IS THE LARGE AREA OF HIGH PRESSURE CENTERED OVER CENTRAL
TEXAS PUSHING THE TROUGH EASTWARD. THE GRADIENT AROUND THE RIDGE OF
HIGH PRESSURE IS THE CAUSE FOR THE HIGH WINDS OVER THE AREA.

.SHORT TERM (TONIGHT THROUGH FRIDAY NIGHT)...
THE LARGE RIDGE OF HIGH PRESSURE OVER CENTRAL TEXAS WILL MOVE
EASTWARD AS THE UPPER LOW OVER THE NEW ENGLAND STATES AND CANADIAN
MARITIMES PULLS OUT TO THE NORTHEAST. THE TROUGH FROM THE UPPER LOW
TO THE NORTH EXTENDS SOUTHWARD ACROSS THE BAHAMAS AND CENTRAL CUBA.
THIS TROUGH AND THE RIDGE OF HIGH PRESSURE NORTHWEST OF THE KEYS WILL
BE THE BLOCKING MECHANISM KEEPING NOW TROPICAL STORM OTTO EAST OF THE
BAHAMAS AND HEADING NORTH. 15 TO 20 MPH WINDS ACROSS THE ISLAND
TERMINALS WITH HIGHER GUSTS AND NEAR 20 KNOTS WITH GUSTS NEAR 25 KNOTS
AND SOME UP TO 30 KNOTS WILL CONTINUE THIS EVENING FROM THE NORTHEAST
TO EAST. WINDS WILL HOLD ON OVERNIGHT AS DRAINAGE WINDS KEEP THE COOL
AIR ADVECTION ACROSS THE UPPER KEYS ESPECIALLY. THE RIDGE WILL SHIFT
EASTWARD TONIGHT AND EASE THE PRESSURE GRADIENT ACROSS THE KEYS AREA
RESULTING IN WINDS RELAXING A BIT TONIGHT INTO THE MORNING. THE RIDGE
CONTINUES TO MOVE TO THE EAST AND SLIGHTLY SOUTHWARD WITH THE
GRADIENT RELAXING MORE ON FRIDAY BUT THERE WILL BE ONE MORE NIGHT OF
SURGING WINDS FRIDAY NIGHT DUE TO THE COOL AIR DRAINAGE OFF THE
MAINLAND. HAVE REDUCED TEMPERATURES SLIGHTLY WITH UPPER 60S TO NEAR
70 ALONG THE UPPER KEYS AND 70 TO 75 FROM THE MIDDLE KEYS WEST. NO
POPS IN THE FORECAST THROUGH FRIDAY NIGHT AS PWATS ARE BELOW 1 INCH
AT THE GEIGER KEY INTEGRATED PWAT SOUNDER...AND NEAR 1 INCH FROM THE
MORNING SOUNDING...AND MODEL PWATS STAY WELL BELOW NORMAL FOR THIS
TIME OF YEAR.

&&

.LONG TERM (SATURDAY THROUGH THURSDAY)...
THE RIDGE OF HIGH PRESSURE WILL WEAKEN AS IT MOVES EASTWARD OVER THE
WESTERN NORTH ATLANTIC. THE WINDS WILL RELAX WITH THE WEAKENING OF
THE RIDGE WITH GENTLE TO MODERATE BREEZES ARRIVING LATE SATURDAY TO
EARLY SUNDAY. A WEAK AREA OF LOWER PRESSURE SOUTH OF CUBA IN THE
WESTERN CARIBBEAN SEA WILL RIDE ALONG THE REMNANT TROUGH PROVIDING A
BIT MORE MOISTURE INTO THE FORECAST FOR SUNDAY AND MONDAY...20
PERCENT POPS...AND MORE SO TUESDAY AND WEDNESDAY...WITH 30 PERCENT
POPS. THE FALL SEASON ASTRONOMICAL HIGH TIDES SHOULD ARRIVE THIS
WEEKEND WITH TIDES RUNNING BETWEEN 1.8 AND 2.2 FEET ABOVE MEAN HIGH
TIDE. THE ANTICIPATED IMPACTS WILL BE TIDE WATERS FLOWING INTO THE
DRAINAGE SYSTEMS AND POOLING IN THE TYPICAL LOW LYING AREAS AROUND THE
ISLAND CHAIN. DRIVERS SHOULD TAKE CARE DRIVING THROUGH THESE AREAS.

&&

.MARINE...
A SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR ALL KEYS COASTAL WATERS
DUE TO FRESH TO STRONG NORTH TO NORTHEAST WINDS THIS MORNING. WINDS
WILL LULL SLIGHTLY THIS AFTERNOON WITH ANOTHER WIND SURGE EXPECTED
THIS EVENING. HIGH PRESSURE OVER THE SOUTHEAST UNITED STATES AND
FLORIDA PENINSULA WILL SLOWLY ERODE FRIDAY THROUGH THE WEEKEND
SLACKENING WINDS THROUGH THE PERIOD. BY SATURDAY...NO EXERCISE
CAUTION HEADLINES OR ADVISORIES WILL BE NECESSARY FOR ALL KEYS
COASTAL WATERS.

&&

.AVIATION...
WE EXPECT VFR CONDITIONS THIS EVENING AT OUR TERMINALS. NORTHEAST
WINDS TO 20 KNOTS MAY CREATE CROSSWINDS GREATER THAN 10 KNOTS ON THE
EAST-WEST RUNWAYS.

&&

.CLIMATE...
ON THIS DATE IN KEYS WEATHER HISTORY...IN 1989...THE HIGH TEMPERATURE
AT THE KEY WEST INTERNATIONAL AIRPORT WAS 90 DEGREES. THIS SET THE
RECORD HIGH TEMPERATURE FOR KEY WEST 21 YEARS AGO.

&&

.PRELIMINARY POINT TEMPS/POPS...
KEY WEST  73  84  75  85 / 0 0 0 0
MARATHON  70  84  74  85 / 0 0 0 0

&&

.KEY WATCHES/WARNINGS/ADVISORIES...
FL...NONE.
GM...SMALL CRAFT ADVISORY UNTIL 6 AM EDT FRIDAY FOR GMZ031-GMZ032-GMZ033-
     GMZ052-GMZ053-GMZ054-GMZ072-GMZ073-GMZ074-GMZ075.

&&

PUBLIC/MARINE.........BWC
AVIATION/NOWCASTS.....DFM
DATA COLLECTION.......ROSS

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