688
WTNT42 KNHC 101435
TCDAT2
HURRICANE FRED DISCUSSION NUMBER 12
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072009
1100 AM AST THU SEP 10 2009
VISIBLE SATELLITE IMAGERY SHOWS THAT FRED STILL HAS AN EYE
SURROUNDED BY DEEP CONVECTION...ALTHOUGH IT IS NOT AS DISTINCT AS
IT WAS YESTERDAY. THE CLOUD PATTERN HAS BECOME A LITTLE BIT
ELONGATED DUE TO SOUTHERLY SHEAR THAT IS BEGINNING TO AFFECT THE
HURRICANE. T-NUMBERS HAVE COME DOWN AND SUPPORT AN INITIAL
INTENSITY OF 85 KNOTS. BECAUSE FRED IS HEADING TOWARD A HOSTILE
ENVIRONMENT OF STRONG SHEAR AND COOL WATERS...THE OFFICIAL FORECAST
CALLS FOR A GRADUAL WEAKENING. FRED COULD BECOME A REMNANT LOW BY
THE END OF THE FORECAST PERIOD OF EVEN EARLIER. THIS IS IN GOOD
AGREEMENT WITH THE SHIPS MODEL WHICH DISSIPATES THE CYCLONE AT 96
HOURS. BOTH THE GFDL AND HWRF MODELS MAINTAIN FRED AS STRONG
TROPICAL STORM OR HURRICANE BUT WITH SUCH PREVAILING HOSTILE
ENVIRONMENT...THIS IS NOT REALISTIC.
THE BEST ESTIMATE OF THE INITIAL MOTION IS 320 DEGREES AT 6 KNOTS.
HOWEVER...THE STEERING CURRENTS ARE FORECAST TO COLLAPSE AND FRED
IS EXPECTED TO SLOW DOWN AND DRIFT NORTHWARD OR MOST LIKELY IT WILL
MEANDER FOR TWO OR THREE DAYS. BY THEN...A RIDGE IS FORECAST TO
DEVELOP NORTH OF FRED...FORCING THE CYCLONE TO TAKE A MORE
WEST-NORTHWEST PATH AS INDICATED IN THE OFFICIAL FORECAST. MOST OF
THE TRACK GUIDANCE...PRIMARILY THE GLOBAL GFS AND THE ECMWF ARE
FORECASTING THE WESTWARD BEND. BY THEN...GIVEN THE PREVAILING
STRONG SHEAR FRED IS EXPECTED TO BE NO MORE THAN A WEAK DISTURBANCE
STEERED BY THE LOW-LEVEL FLOW.
FORECAST POSITIONS AND MAX WINDS
INITIAL 10/1500Z 16.8N 35.1W 85 KT
12HR VT 11/0000Z 17.5N 35.4W 75 KT
24HR VT 11/1200Z 18.0N 35.5W 65 KT
36HR VT 12/0000Z 18.2N 35.2W 55 KT
48HR VT 12/1200Z 18.6N 34.8W 45 KT
72HR VT 13/1200Z 20.5N 35.0W 35 KT
96HR VT 14/1200Z 22.0N 38.0W 30 KT
120HR VT 15/1200Z 24.0N 42.0W 25 KT...REMNANT LOW
FORECASTER AVILA
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page