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| #6261 (Received by flhurricane at: 10:40 PM 27.Aug.2004) TCDAT1 HURRICANE FRANCES DISCUSSION NUMBER 13 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT FRI AUG 27 2004 BASED UPON SSMI IMAGES AND INFRARED SATELLITE ANIMATION...FRANCES APPEARS TO HAVE GONE THROUGH AN EYEWALL REPLACEMENT CYCLE WITH THE NET RESULT BEING A LARGER EYE DIAMETER AND A LIKELY DECREASE IN WIND SPEED. THIS IS SOMEWHAT CONFIRMED BY THE FACT THAT TAFB DETERMINED A T5.5 AND SAB A T5.0...COMPARED TO TAFB HAVING THE SAME INTENSITY AND SAB DOWN ONE-HALF T NUMBER FROM 6 HOURS AGO. GLOBAL WEATHER ALSO CAME IN WITH A T5.0 FOR THIS FORECAST CYCLE THE INITIAL INTENSITY WILL REMAIN AT 100 KTS. GENERALLY...THE NEXT PHASE AFTER ONE OF THESE CYCLES IS INTENSIFICATION. THE MOTION IS 310/10. FRANCES CONTINUES MOVING TOWARD THE NORTHWEST AND IS RIGHT ON THE OFFICIAL FORECAST TRACK. AS MENTIONED IN THE PREVIOUS DISCUSSION...THE MOTION TO THE NORTHWEST IS EXPECTED TO BE SHORT LIVED AS THE SHORTWAVE TROUGH LOCATED DUE NORTH OF FRANCES MOVES EASTWARD AND THE RIDGE BUILDS BACK IN BEHIND THE TROUGH. THIS SHOULD TURN FRANCES BACK TO THE WEST-NORTHWEST ON SATURDAY. ALL OF THE MODELS NOW AGREE THAT THE HIGH ZONAL FLOW FORECAST TO DEVELOP ACROSS THE NORTHERN U.S. AND THE NORTH ATLANTIC AFTER 48HR WILL ALLOW FOR A STRONG SUBTROPICAL RIDGE TO THE SOUTH TO EXTEND EAST-WEST FROM THE AZORES TO BERMUDA AND INTO THE SOUTHEASTERN U.S. THE NHC MODEL SUITE IS A LITTLE MORE DIVERGENT IN THE 4 AND 5 DAY TIME PERIODS THAN THE PREVIOUS PACKAGE...BUT THE CONSENSUS MODEL IS ALMOST UNCHANGED. THE OFFICIAL FORECAST FOR THIS CYCLE FOLLOWS THE PREVIOUS OFFICIAL OUT TO 72 HOURS BUT GENTLY SHIFTS THE 4 AND 5 DAY FORECAST POSITIONS CLOSER TO THE GUNA POSITIONS. THIS FORECAST IS ALSO VERY CLOSE TO THE UKMET SOLUTION. FRANCES IS FORECAST TO REMAIN IN A LOW SHEAR ENVIRONMENT AND OVER INCREASING SSTS THROUGHOUT THE PERIOD. THE SHIPS INTENSITY MODEL CONTINUES TO KEEP FRANCES A MAJOR HURRICANE FOR THE NEXT FIVE DAYS. THERE WILL LIKELY BE SEVERAL FLUCTUATIONS...AS MENTIONED ABOVE...IN THE INTENSITY OVER THIS PERIOD OF TIME...BUT CATEGORY FOUR INTENSITY SEEMS LIKELY SOME TIME DURING THAT PERIOD...AND CATEGORY 5 STRENGTH IS EVEN POSSIBLE. FORECASTER JARVINEN FORECAST POSITIONS AND MAX WINDS INITIAL 28/0300Z 16.3N 50.5W 100 KT 12HR VT 28/1200Z 17.2N 51.7W 105 KT 24HR VT 29/0000Z 18.3N 53.3W 110 KT 36HR VT 29/1200Z 19.1N 54.9W 115 KT 48HR VT 30/0000Z 19.8N 56.8W 115 KT 72HR VT 31/0000Z 20.9N 60.9W 115 KT 96HR VT 01/0000Z 22.1N 65.4W 115 KT 120HR VT 02/0000Z 23.5N 70.0W 115 KT |
