Hurricane FELIX

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HURRICANE FELIX DISCUSSION NUMBER   9
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL062007
500 PM EDT SUN SEP 02 2007
 
THERE HAS BEEN RAPID STRENGTHENING OF THE HURRICANE TODAY.  FELIX
HAS A SPECTACULAR PRESENTATION ON SATELLITE IMAGES WITH A WELL-
DEFINED EYE EMBEDDED IN A CIRCULAR CENTRAL DENSE OVERCAST.  THE
HURRICANE HUNTER CREW REPORTED A STADIUM EFFECT IN THE EYE AND THAT
THE EYE DIAMETER HAD SHRUNK TO 12 N MI.  THE AIR FORCE PLANE ALSO
MEASURED A PEAK 700 MB FLIGHT LEVEL WIND OF 132 KT AND...FOR A
SYSTEM OF SUCH CONVECTIVE VIGOR...THE 90 PER CENT RATIO OF SURFACE
TO FLIGHT LEVEL WINDS SHOULD CERTAINLY APPLY HERE.  THIS WOULD
EQUATE TO PEAK SURFACE WINDS OF ABOUT 120 KT.  A GPS DROPSONDE IN
THE NORTHERN EYEWALL MEASURED A SURFACE WIND OF 128 KT BUT THIS IS
A SPOT WIND THAT IS NOT NECESSARILY REPRESENTATIVE OF A 1-MINUTE
AVERAGE.  THUS THE CURRENT INTENSITY IS SET AT 120 KT.  A CENTRAL
PRESSURE OF 957 MB WAS MEASURED BY DROPSONDE...WITH 15 KT WINDS AT
THE SURFACE.  SO THE MINIMUM PRESSURE IS ESTIMATED TO BE SLIGHTLY
LOWER OR 956 MB.  THIS CORRESPONDS TO A FALL IN CENTRAL PRESSURE AT
A RATE OF 3.4 MB PER HOUR OVER THE PAST 7 HOURS OR SO...WHICH IS
ONE OF THE MORE RAPID DEEPENING RATES WE HAVE OBSERVED.  FELIX WILL
REMAIN IN A VERY LOW SHEAR TROPOSPHERIC ENVIRONMENT AND WILL BE
PASSING OVER WATERS OF EXTREMELY HIGH OCEANIC HEAT CONTENT OVER THE
NEXT COUPLE OF DAYS.  IN ADDITION...TO EXACERBATE THE SITUATION...
THERE IS A WARM EDDY OVER THE CENTRAL CARIBBEAN THAT FELIX IS
PROJECTED TO MOVE OVER IN 12 HOURS OR SO.  THE OFFICIAL INTENSITY
FORECAST COULD BE CONSERVATIVE AND THERE IS CERTAINLY THE POTENTIAL
FOR US TO HAVE ANOTHER CATEGORY FIVE HURRICANE ON OUR HANDS BEFORE
ALL IS SAID AND DONE.

A SWIFT WEST-NORTHWESTWARD MOTION...285/17...CONTINUES.  I HAVE MADE
ESSENTIALLY NO CHANGE TO THE TRACK FORECAST AND THE REASONING
BEHIND IT.  A WELL-ESTABLISHED DEEP LAYER RIDGE TO THE NORTH OF
FELIX SHOULD MORE OR LESS MAINTAIN THE CURRENT MOTION FOR THE NEXT
DAY OR TWO.  SOME SLOWING OF THE FORWARD SPEED IS CALLED FOR BY DAY
3 AS THE RIDGE WEAKENS.  THE EXACT FATE OF FELIX OVER THE GULF OF
MEXICO REMAINS SOMEWHAT UNCERTAIN SINCE THERE IS SOME POSSIBILITY
THAT A TROUGH OVER THE CENTRAL U.S. COULD ERODE THE RIDGE MORE THAN
CURRENTLY ANTICIPATED.  HOWEVER IT SHOULD BE NOTED THAT NONE OF THE
DYNAMICAL TRACK GUIDANCE MODELS TURN FELIX SIGNIFICANTLY TO THE
RIGHT THROUGH 120 HOURS.  IN FACT...THE LATEST GFDL MODEL RUN HAS
SHIFTED WELL TO THE SOUTH OF THE OTHER GUIDANCE.  AGAIN...BECAUSE
OF THE UNCERTAINTIES...WE ADVISE AGAINST PUTTING TOO MUCH EMPHASIS
ON THE EXACT NHC FORECAST TRACK AT 4 AND 5 DAYS. 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      02/2100Z 13.6N  72.0W   120 KT
 12HR VT     03/0600Z 14.1N  74.5W   125 KT
 24HR VT     03/1800Z 14.8N  78.0W   130 KT
 36HR VT     04/0600Z 15.4N  81.1W   135 KT
 48HR VT     04/1800Z 16.0N  83.5W   135 KT
 72HR VT     05/1800Z 17.3N  87.7W   135 KT
 96HR VT     06/1800Z 19.5N  91.5W    80 KT
120HR VT     07/1800Z 21.5N  95.0W    90 KT
 
$$
FORECASTER PASCH
 
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