000
WTPZ44 KNHC 102042
TCDEP4
HURRICANE FLOSSIE DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   EP092007
200 PM PDT FRI AUG 10 2007
 
THE FIRST SEVERAL VISIBLE IMAGES OF THE DAY REVEAL AN INCREASINGLY
DISTINCT EYE...DECENT OUTFLOW IN ALL QUADRANTS...AND THAT
CONVECTION HAS BEEN DEEPENING IN THE NORTHWESTERN QUADRANT WHERE IT
HAD PREVIOUSLY BEEN A BIT THIN.  AN SSMIS OVERPASS FROM 1714Z ALSO
DEPICTS A SOLID AND SYMMETRIC EYEWALL WRAPPING ESSENTIALLY ALL THE
WAY AROUND THE CENTER.  DVORAK INTENSITY ESTIMATES AT 18Z FROM TAFB
AND SAB WERE A CONSENSUS 77 KT...SO THE ADVISORY INTENSITY IS
ADJUSTED UPWARD TO 75 KT.  A QUIKSCAT OVERPASS AT 1525Z COULD NOT
RESOLVE ANY HURRICANE-FORCE WINDS...BUT IT DID CONFIRM THAT
FLOSSIE'S OVERALL WIND FIELD IS FAIRLY SMALL...WITH WINDS OF
TROPICAL STORM FORCE EXTENDING NO FARTHER FROM THE CENTER THAN
ABOUT 60 N MI.
 
FLOSSIE CONTINUES DUE WESTWARD OR 270 DEGREES AT ABOUT 11 KT...WITH
STEERING PROVIDED BY THE SUBTROPICAL RIDGE TO ITS NORTH.  ALL OF
THE MODEL GUIDANCE FORECASTS ENOUGH RIDGING TO PERSIST TO THE NORTH
OF FLOSSIE FOR THE NEXT FIVE DAYS TO FORCE THE SYSTEM GENERALLY
WESTWARD OR WEST-NORTHWESTWARD THROUGHOUT THAT PERIOD.  NOTABLE
DIFFERENCES EXIST BETWEEN THE MODELS...HOWEVER...ESPECIALLY IN THE
FUTURE LATITUDE OF FLOSSIE.  THE HWRF IS THE NORTHERN OUTLIER BUT
SEEMS TO TAKE THE CYCLONE TOO FAR NORTH EVEN EARLY ON IN THE
FORECAST.  MEANWHILE THE ECMWF AND UKMET ARE MUCH FARTHER
SOUTH...ON THE OTHER EXTREME OF THE GUIDANCE ENVELOPE.  THE NAVY
MODELS...GFS...AND THE CONSENSUS ARE ROUGHLY IN THE MIDDLE.  GIVEN
THE SIGNIFICANT MODEL SPREAD...AND THAT THE CONSENSUS IS CLOSE TO
THE PREVIOUS OFFICIAL FORECAST...NO SIGNIFICANT CHANGES HAVE BEEN
MADE IN THE NEW OFFICIAL TRACK.
 
OCEAN AND ATMOSPHERIC CONDITIONS APPEAR TO BE CONDUCIVE FOR A LITTLE
MORE INTENSIFICATION.  SEA-SURFACE TEMPERATURES ALONG THE FORECAST
TRACK SHOULD REMAIN AT LEAST 27C FOR ABOUT 24 MORE HOURS...WITHIN A
CONTINUED WEAK SHEAR ENVIRONMENT.  THE OFFICIAL FORECAST PEAKS AT
85 KT IN 24 HOURS IN CLOSE AGREEMENT WITH ALL AVAILABLE INTENSITY
GUIDANCE.  THE WATERS SHOULD GRADUALLY COOL BENEATH FLOSSIE BEYOND
24 HOURS...AND SOUTHERLY WIND SHEAR IS FORECAST BY THE GLOBAL MODELS
TO START INCREASING IN ABOUT THREE DAYS.  AS A RESULT...FLOSSIE IS
FORECAST TO SLOWLY WEAKEN ON DAYS TWO AND THREE...FOLLOWED BY MORE
WEAKENING AS A TROPICAL STORM LATE IN THE FORECAST PERIOD.  NONE OF
THE AVAILABLE INTENSITY GUIDANCE FORECASTS FLOSSIE TO BE A
HURRICANE BEYOND 72 HOURS.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      10/2100Z 12.6N 137.2W    75 KT
 12HR VT     11/0600Z 12.7N 139.0W    80 KT
 24HR VT     11/1800Z 13.1N 141.3W    85 KT
 36HR VT     12/0600Z 13.6N 143.6W    80 KT
 48HR VT     12/1800Z 14.1N 146.0W    75 KT
 72HR VT     13/1800Z 15.0N 150.5W    65 KT
 96HR VT     14/1800Z 16.5N 155.0W    55 KT
120HR VT     15/1800Z 18.0N 159.5W    45 KT
 
$$
FORECASTER KNABB