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#9665 (Received by flhurricane at: 4:50 AM 23.Sep.2004) TCDAT4 TROPICAL STORM IVAN DISCUSSION NUMBER 69 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT THU SEP 23 2004 IVAN REMAINS A POORLY-ORGANIZED TROPICAL STORM...WITH MOST OF THE DEEP CONVECTION BEING SHEARED TO THE NORTHEAST OF THE LOW-LEVEL CENTER. THERE IS STILL A POSSIBILITY OF THE SHEAR RELAXING...AND SOME INTENSIFICATION...BEFORE THE CENTER CROSSES THE COAST. HOWEVER...THE WINDOW OF OPPORTUNITY FOR THIS TO HAPPEN IS CLOSING. LATEST CENTER FIXES INDICATE AN INCREASE IN FORWARD SPEED AND THE INITIAL MOTION ESTIMATE IS 300/13. IVAN IS BEING STEERED MAINLY BY A LOW- TO MID-LEVEL RIDGE TO ITS NORTH...WHICH THE GFS MODEL PREDICTS TO WEAKEN WITHIN THE NEXT 24 HOURS. THUS SOME SLOWING OF THE FORWARD SPEED IS ANTICIPATED. THE GLOBAL MODELS SHOW A SHARP LEFTWARD TURN IN 24 TO 48 HOURS IN RESPONSE TO A MID- TO UPPER-LEVEL TROUGH OVER THE SOUTHWESTERN GULF. THE OFFICIAL FORECAST ASSUMES THAT IVAN WILL NOT BE A DEEP ENOUGH CYCLONE TO RESPOND SIGNIFICANTLY TO THIS TROUGH. THE CURRENT OFFICIAL TRACK IS A LITTLE TO THE LEFT OF THE PREVIOUS ONE...AND IN BETWEEN THE MEDIUM AND SHALLOW LAYER BAM TRACKS. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 23/0900Z 28.2N 91.6W 35 KT 12HR VT 23/1800Z 29.2N 93.4W 40 KT 24HR VT 24/0600Z 30.1N 95.0W 35 KT...INLAND 36HR VT 24/1800Z 30.7N 96.1W 30 KT...INLAND 48HR VT 25/0600Z 31.0N 97.0W 20 KT...INLAND...DISSIPATING 72HR VT 26/0600Z 31.1N 98.0W 20 KT...INLAND...REMNANT LOW 96HR VT 27/0600Z...DISSIPATED |