[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT41 KNHC 280227
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


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