Hurricane IVAN
ZCZC MIATCDAT4 ALL TTAA00 KNHC DDHHMM HURRICANE IVAN DISCUSSION NUMBER 14 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT SUN SEP 05 2004 LATEST SATELLITE IMAGERY INDICATES THAT IVAN HAS INTENSIFIED AND MAXIMUM WINDS ARE ESTIMATED TO BE NEAR 110 KT. AS NOTED EARLIER...IT IS UNPRECEDENTED TO HAVE A HURRICANE THIS STRONG AT SUCH A LOW LATITUDE IN THE ATLANTIC BASIN. THE EYE IS EMBEDDED IN CLOUD TOPS COLDER THAN -70 DEG C AND THE UPPER-LEVEL OUTFLOW IS QUITE SYMMETRIC AND STRONG. THE OFFICIAL WIND SPEED FORECAST IS CONSERVATIVE BECAUSE OF OUR LIMITED SKILL IN PREDICTING INTENSITY CHANGE...AND OBVIOUSLY IVAN COULD BECOME STRONGER THAN INDICATED HERE. INITIAL MOTION IS WNW...285/18. A STRONG DEEP-LAYER HIGH IS LIKELY TO BE MAINTAINED TO THE NORTH OF THE HURRICANE...AND THIS PATTERN SHOULD MAINTAIN ABOUT THE SAME STEERING FLOW FOR IVAN OVER THE NEXT FEW DAYS. LATE IN THE PERIOD...GLOBAL MODELS FORECASTS AT THE 500 MB LEVEL ARE SHOWING A TROUGH OVER THE EAST-CENTRAL UNITED STATES AND AN ANTICYCLONE OVER THE WESTERN ATLANTIC WITH A RIDGE EXTENDING TO FLORIDA. HOWEVER THE DETAILS VARY FROM MODEL TO MODEL...AND THERE IS UNCERTAINTY IN HOW MUCH IVAN WILL TURN TOWARD THE NORTHWEST BY DAY 5. THE OFFICIAL FORECAST IS CLOSE TO A CONSENSUS OF THE DYNAMICAL MODELS WHICH EXCLUDES THE GFS. THE LATTER MODEL IS INITIALIZING THIS TROPICAL CYCLONE TOO WEAK AND SHALLOW...SO ITS MORE SOUTHERN TRACK IS CONSIDERED UNREALISTIC. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 05/2100Z 10.4N 47.7W 110 KT 12HR VT 06/0600Z 11.0N 50.4W 115 KT 24HR VT 06/1800Z 11.9N 54.0W 120 KT 36HR VT 07/0600Z 12.8N 57.5W 125 KT 48HR VT 07/1800Z 13.6N 61.0W 125 KT 72HR VT 08/1800Z 15.5N 66.5W 125 KT 96HR VT 09/1800Z 18.5N 71.5W 70 KT...INLAND 120HR VT 10/1800Z 21.5N 76.0W 75 KT...OVER WATER $$ NNNN