826
WTNT42 KNHC 090247
TCDAT2
HURRICANE FRED DISCUSSION NUMBER 6
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL072009
1100 PM AST TUE SEP 08 2009
THE LATEST FEW INFRARED IMAGES FROM METEOSAT-9 INDICATE THAT FRED
HAS DEVELOPED AN EYE...FOLLOWING THE TREND OBSERVED IN 1934 UTC
WINDSAT DATA AND 2112 UTC SSM/IS DATA FROM EARLIER THIS EVENING.
THE EYE IS SURROUNDED BY DEEP CONVECTION WITH VERY COLD CLOUD TOPS
TO -80 C...AND THE CENTRAL DENSE OVERCAST IS EXPANDING AND BECOMING
MORE AXISYMMETRIC. TWO RECENT AMSU OVERPASSES YIELDED INTENSITY
ESTIMATES OF 68 KT AND 70 KT FROM UW-CIMSS...AND FRED IS BEING
UPGRADED TO A 65-KT HURRICANE IN THIS ADVISORY.
FRED HAS BEGUN TO SLOW DOWN AND TURN TOWARD THE WEST-NORTHWEST WITH
AN ESTIMATED INITIAL MOTION OF 295/10. THE NARROW RIDGE THAT HAS
BEEN NORTH OF THE HURRICANE IS NOW BREAKING DOWN DUE TO TWO
SHORTWAVE MID- TO UPPER-LEVEL TROUGHS LOCATED NEAR 27N 37W AND NEAR
THE CANARY ISLANDS. AS A RESULT...FRED WILL CONTINUE TO TURN
TOWARD THE NORTHWEST THEN NORTH OVER THE NEXT 48-72 HOURS. THE
MODEL ENVELOPE REMAINS TIGHTLY-CLUSTERED...AND THE NEW OFFICIAL
FORECAST DID NOT HAVE TO BE ADJUSTED FROM THE PREVIOUS FORECAST BY
MUCH. INTERESTINGLY...THE GFDL AND HWRF HAVE BOTH CONSISTENTLY
BEEN ON THE WESTERN EDGE OF THE MODEL ENVELOPE...AND THEY HAVE DONE
A BETTER JOB THAN THE OTHER MODELS BY NOT PULLING FRED NORTHWARD TOO
SOON. THIS COULD BE AN INDICATION THAT FRED MIGHT NOT TURN AS
SHARPLY TO THE NORTH AS INDICATED IN THE OFFICIAL FORECAST...AND
FUTURE FORECASTS MAY REQUIRE SOME SHIFTING TO THE WEST.
FRED APPEARS TO HAVE A CLEAR PATH FOR CONTINUED STRENGTHENING FOR
THE NEXT 24 HOURS OR SO DUE TO SUFFICIENTLY WARM SSTS AND LOW
SHEAR. HOWEVER...NONE OF THE GUIDANCE SHOWS FAST STRENGTHENING...
AND THE SHIPS RAPID INTENSIFICATION INDEX IS ONLY 21 PERCENT AT THE
MOMENT. THEREFORE...THE OFFICIAL FORECAST CONTINUES TO PEAK FRED
AT 80 KT IN 24 HOURS...FOLLOWED BY GRADUAL WEAKENING BEGINNING AT
36 HOURS ONCE SOUTHWESTERLY SHEAR BEGINS TO INCREASE. SSTS ONLY
DECREASE GRADUALLY NORTH OF FRED...AND IT APPEARS THAT THE SHEAR
AND A DRIER MID-LEVEL ENVIRONMENT WILL PLAY THE BIGGEST ROLE IN
MODULATING THE INTENSITY BEYOND 72 HOURS.
FORECAST POSITIONS AND MAX WINDS
INITIAL 09/0300Z 12.6N 30.6W 65 KT
12HR VT 09/1200Z 13.3N 31.7W 75 KT
24HR VT 10/0000Z 14.5N 33.1W 80 KT
36HR VT 10/1200Z 15.7N 34.0W 75 KT
48HR VT 11/0000Z 16.8N 34.2W 70 KT
72HR VT 12/0000Z 18.3N 34.0W 60 KT
96HR VT 13/0000Z 20.0N 33.5W 45 KT
120HR VT 14/0000Z 23.0N 34.0W 30 KT
FORECASTER BERG
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