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| #9360 (Received by flhurricane at: 12:33 AM 21.Sep.2004) TCDAT2 HURRICANE KARL DISCUSSION NUMBER 18 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT MON SEP 20 2004 KARL HAS BEEN STRENGTHENING OVER THE PAST SIX HOURS AND DVORAK T-NUMBERS ARE ONCE AGAIN UP TO 6.5 FROM BOTH TAFB AND SAB WHILE REMAINING STEADY AT 5.5 FROM AFWA. CLOUD TOP TEMPERATURES TEND TO SHOW UP A LITTLE COOLER FOR MET-8 AS COMPARED TO GOES-12...WHICH PROBABLY EXPLAINS WHY TAFB AND SAB ARE A LITTLE HIGHER THAN AFWA. REGARDLESS...BOTH SATELLITES REPRESENTATIONS SHOW A WIDE BAND OF COOLING CLOUD TOPS SURROUNDING THE EYE. IN ADDITION...A 2207Z TRMM PASS REVEALED THAT THE STRENGTHENING EYEWALL IS BECOMING MORE ENCLOSED WITH ONLY A SMALL OPENING ON THE SOUTH SIDE. SINCE CI NUMBERS HAVE BEEN HOLDING STEADY BETWEEN 6.0 AND 6.5 FOR THE PAST 24 HOURS AND THE CONVECTIVE PATTERN IS IMPROVING...THE INITIAL INTENSITY IS SET AT 120 KT. THE INITIAL MOTION IS A LITTLE MORE TO THE RIGHT AT 315/9. THE MODEL GUIDANCE WANTS TO RUN KARL OUT OF THE GATES AT A FASTER PACE FOR THE FIRST 24 HOURS...MORE LIKE 12 KNOTS...BUT THE OFFICIAL FORECAST HOLDS IT BACK A BIT IN LINE WITH CURRENT TRENDS. HOWEVER... ACCELERATION IS ANTICIPATED OVER THE NEXT 24 HOURS AS THE SYSTEM MOVES AROUND THE MID-LEVEL RIDGE TO ITS EAST AND HEADS TOWARDS A DEEP TROUGH NEAR THE CANADIAN MARITIMES. KARL SHOULD CONTINUE TO STRENGTHEN OVER THE NEXT 6 HOURS AND RETAIN A MAXIMUM INTENSITY THROUGH 24 HOURS AS IT BEGINS TO ROUND THE POINT OF RECURVATURE. THE HURRICANE WILL THEN GRADUALLY WEAKEN BETWEEN 24 AND 48 HOURS...AND THEN MORE QUICKLY THEREAFTER AS SHEAR INCREASES AND SSTS COOL BELOW 26C AFTER 48 HOURS. EXTRATROPICAL TRANSITION IS EXPECTED BY 96 HOURS WITH KARL BECOMING INCORPORATED INTO THE DEEP POLAR VORTEX JUST EAST OF THE CANADIAN MARITIMES. FORECASTER BERG/JARVINEN FORECAST POSITIONS AND MAX WINDS INITIAL 21/0300Z 19.1N 47.4W 120 KT 12HR VT 21/1200Z 20.1N 48.5W 125 KT 24HR VT 22/0000Z 22.3N 49.8W 125 KT 36HR VT 22/1200Z 25.4N 50.1W 120 KT 48HR VT 23/0000Z 28.5N 49.0W 115 KT 72HR VT 24/0000Z 36.0N 45.0W 100 KT 96HR VT 25/0000Z 44.0N 44.5W 80 KT...EXTRATROPICAL 120HR VT 26/0000Z 49.0N 47.0W 60 KT...EXTRATROPICAL |
