ZCZC MIATCDAT2 ALL TTAA00 KNHC DDHHMM HURRICANE KARL DISCUSSION NUMBER 16 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT MON SEP 20 2004 SATELLITE IMAGES INDICATE THAT KARL IS NOT AS CIRCULAR AS YESTERDAY WITH THE CLOUD SHIELD SHOWING ASYMMETRIES IN THE EASTERN AND NORTHERN SEMICIRCLES. THIS PATTERN SUGGESTS SOME SHEAR IS PRESENT...CONFIRMED BY THE GFS AND CIMSS ANALYSES SHOWING ABOUT 10-15 KT OF SHEAR FROM THE SOUTHWEST. THE CLOUD PATTERN NEAR THE INNER CORE REMAINS RAGGED AND T-NUMBERS ARE FALLING. HOWEVER A RECENT SSMI OVERPASS SHOWED NO EVIDENCE OF THE INNER EYEWALL SEEN ON EARLIER MICROWAVE IMAGES. THIS SUGGESTS THAT THE PREVIOUS EYEWALL CYCLE IS COMPLETE. ON THE OTHER HAND THE EYE WAS ALSO OPEN ON THE SOUTH SIDE. GIVEN THE ABOVE FACTORS...THE INTENSITY IS DECREASED A BIT TO 105 KT FOR THIS ADVISORY. A MIDDLE TO UPPER LEVEL TROUGH ALONG 54W IS APPROACHING THE CYCLONE. THE GFS INDICATES THAT SHEAR WILL REMAIN NEAR CURRENT LEVELS UNTIL AFTER 24 HOURS WHEN THE TROUGH RETROGRADES AWAY FROM KARL. THIS SCENARIO SHOULD PROVIDE A PERIOD OF VERY LOW SHEAR OVER WARM WATER NEAR THE CYCLONE'S RECURVATURE POINT... ALL INGREDIENTS FOR INTENSIFICATION BETWEEN 24-48 HOURS. THE OFFICIAL FORECAST IS A COMPROMISE BETWEEN THE SHIPS AND PREVIOUS INTENSITY FORECAST. WIND RADII HAVE BEEN INCREASED BASED ON A 0900 UTC QUIKSCAT PASS AND THIS LARGE SIZE IS HELD CONSTANT THOUGH THE PERIOD. KARL IS STILL MOVING WEST-NORTHWEST OVER THE PAST 6-12 HOURS BUT RECENT SATELLITE PICTURES SUGGEST THAT A MORE NORTHWESTERLY MOTION MAY HAVE BEGUN. THERE REMAINS NO SIGNIFICANT CHANGE TO THE TRACK FORECAST PHILOSOPHY. A DEEP-LAYERED TROUGH CURRENTLY OVER THE WESTERN ATLANTIC IS FORECAST TO DIG SOUTHWARD AND BECOME ANCHORED ALONG 55W. THE OFFICIAL FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY AND IS IN BETWEEN CONU AND THE PREVIOUS FORECAST. THE FORECAST TRACK SHOWS A BIT OF A BEND TO THE LEFT BEYOND 3 DAYS TO REFLECT A DEEP MID-LATITUDE CYCLONE CAPTURING KARL RATHER THAN THE TROPICAL CYCLONE STAYING A SEPARATE ENTITY. FORECASTER BLAKE/LAWRENCE FORECAST POSITIONS AND MAX WINDS INITIAL 20/1500Z 17.9N 46.3W 105 KT 12HR VT 21/0000Z 18.7N 47.4W 105 KT 24HR VT 21/1200Z 20.4N 48.8W 110 KT 36HR VT 22/0000Z 22.5N 49.7W 120 KT 48HR VT 22/1200Z 25.0N 49.8W 120 KT 72HR VT 23/1200Z 32.0N 47.0W 110 KT 96HR VT 24/1200Z 41.0N 44.0W 90 KT 120HR VT 25/1200Z 51.0N 45.0W 65 KT...EXTRATROPICAL $$ NNNN
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Page last modified: Monday, 20-Sep-2004 14:53:57 UTC