[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT44 KNHC 111448
TCDAT4
HURRICANE IVAN DISCUSSION NUMBER  37
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT SAT SEP 11 2004

SATELLITE IMAGES SHOW THAT IVAN CONTINUES TO BE WELL-ORGANIZED WITH
A DISTINCT EYE SURROUNDED BY VERY DEEP CONVECTION. AN ELONGATED
UPPER-LOW OVER THE BAHAMAS IS DISRUPTING THE OUTFLOW A LITTLE BIT
IN THE NORTHERN SEMICIRCLE. THE OUTFLOW IS WELL-ESTABLISHED
ELSEWHERE. INITIAL INTENSITY IS REDUCED TO 125 KNOTS ASSUMING SOME
WEAKENING DUE TO THE INTERACTION WITH JAMAICA. A BETTER ESTIMATE OF
THE INITIAL INTENSITY WILL BE AVAILABLE WHEN ANOTHER RECONNAISSANCE
PLANE REACHES THE AREA LATER TODAY. THE SHEAR IS LOW AND THE
HURRICANE WILL BE MOVING OVER AN AREA OF HIGH OCEAN HEAT CONTENT.
THEREFORE IVAN COULD GAIN SOME STRENGTH BEFORE REACHING CUBA.

THE AVERAGE MOTION DURING THE PAST FEW HOURS HAS BEEN BASICALLY
WESTWARD...PARALLELING THE SOUTH COAST OF JAMAICA. WATER VAPOR
IMAGES SHOW A MID-LEVEL HIGH PRESSURE SYSTEM OVER THE EASTERN GULF
OF MEXICO AND FLORIDA. THIS FEATURE MAY KEEP THE HURRICANE ON A
SLOW WEST TO WEST-NORTHEAST TRACK FOR A LITTLE LONGER.
THEREAFTER...A RIDGE IS FORECAST TO STRENGTHEN OVER THE WESTERN
ATLANTIC AND THE BAHAMAS AND A WEAKNESS SHOULD DEVELOP OVER THE
GULF OF MEXICO. THIS PATTERN CALLS FOR A GRADUAL TURN OF THE
HURRICANE TO THE NORTHWEST AND NORTH-NORTHWEST THROUGH 72 HOURS. A
GENERAL NORTHWARD TRACK IS EXPECTED THEREAFTER. THE OFFICIAL
FORECAST HAS BEEN SHIFTED A LITTLE BIT WESTWARD BASED ON
THE LATEST MODEL GUIDANCE HEAVILY WEIGHTED ON THE GLOBAL MODEL
CONSENSUS.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      11/1500Z 17.9N  78.7W   125 KT
 12HR VT     12/0000Z 18.5N  79.8W   135 KT
 24HR VT     12/1200Z 19.6N  81.0W   135 KT
 36HR VT     13/0000Z 21.0N  82.0W   135 KT
 48HR VT     13/1200Z 22.8N  83.0W   125 KT  OVER WESTERN CUBA
 72HR VT     14/1200Z 27.0N  84.5W   115 KT
 96HR VT     15/1200Z 31.5N  83.9W    65 KT...INLAND
120HR VT     16/1200Z 36.0N  82.0W    25 KT...INLAND


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