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| #149158 (Received by flhurricane at: 4:43 PM 02.Sep.2007) TCDAT1 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 |
