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| #111689 (Received by flhurricane at: 10:31 PM 18.Sep.2006) TCDAT3 HURRICANE HELENE DISCUSSION NUMBER 27 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082006 1100 PM EDT MON SEP 18 2006 ALTHOUGH THE CLOUD PATTERN OF HELENE IS SLIGHTLY ELONGATED TO THE NORTH...THE SATELLITE PRESENTATION OF THE CORE OF THE HURRICANE HAS BECOME MORE IMPRESSIVE OVER THE PAST FEW HOURS. CENTRAL CONVECTION IS COOLING AND THE EYE IS BECOMING BETTER DEFINED. CIRRUS OUTFLOW IS RATHER SYMMETRICAL AND EXPANDING. DVORAK T-NUMBERS OF 5.5 FROM ALL AGENCIES SUPPORT KEEPING THE INTENSITY AT 100 KT AT THIS TIME. THE HURRICANE WILL CONTINUE TO MOVE OVER WARM OCEAN WATERS AND THE VERTICAL SHEAR IS EXPECTED TO REMAIN WEAK OVER THE NEXT COUPLE OF DAYS. STRENGTHENING IS LIKELY AND THE OFFICIAL WIND SPEED FORECAST IS SLIGHTLY HIGHER THAN THE SHIPS...GFDL...AND FSU SUPERENSEMBLE INTENSITY GUIDANCE. INDEED...GIVEN THE INCREASING ORGANIZATION OF THE INNER CORE...THIS INTENSITY FORECAST COULD BE CONSERVATIVE... AND HELENE CERTAINLY HAS THE POTENTIAL TO BECOME A CATEGORY 4 HURRICANE. HELENE IS MOVING SLOWLY WEST-NORTHWESTWARD...300/7. A MORE WESTWARD COMPONENT OF MOTION IS EXPECTED DURING THE NEXT DAY OR SO AS A MID-TROPOSPHERIC RIDGE TEMPORARILY BUILDS TO THE NORTH OF THE TROPICAL CYCLONE. THE GFDL MODEL EVEN DEPICTS A TURN TOWARD THE WEST-SOUTHWEST IN 12 HOURS OR SO. BY 48 HOURS...HOWEVER...A VERY LARGE 500 MB TROUGH MOVING EASTWARD NEAR THE U.S. EAST COAST SHOULD INDUCE A TURN TOWARD THE NORTHWEST AND NORTH-NORTHWEST. IN 3 TO 5 DAYS HELENE SHOULD BEGIN TO BE STEERED BY THE FLOW ON THE SOUTHERN PART OF THE TROUGH AND TURN TOWARD THE NORTH AND NORTHEAST. THE OFFICIAL FORECAST FOR THIS ADVISORY PACKAGE IS IN REASONABLE AGREEMENT WITH THE DYNAMICAL MODEL CONSENSUS AS WELL AS THE GFDL...AND ALSO SIMILAR TO THE PREVIOUS NHC TRACK. FORECAST POSITIONS AND MAX WINDS INITIAL 19/0300Z 24.2N 51.4W 100 KT 12HR VT 19/1200Z 24.6N 52.7W 105 KT 24HR VT 20/0000Z 25.0N 54.4W 110 KT 36HR VT 20/1200Z 25.4N 55.9W 110 KT 48HR VT 21/0000Z 26.7N 57.1W 110 KT 72HR VT 22/0000Z 31.0N 58.0W 100 KT 96HR VT 23/0000Z 35.5N 56.0W 90 KT 120HR VT 24/0000Z 39.0N 51.0W 80 KT $$ FORECASTER PASCH |
