[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT44 KNHC 101443
TCDAT4
HURRICANE IVAN DISCUSSION NUMBER  33
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT FRI SEP 10 2004

VISIBLE SATELLITE IMAGES SHOW THAT THE CLOUD PATTERN ASSOCIATED WITH
IVAN DOES NOT APPEAR AS WELL ORGANIZED AS IT WAS YESTERDAY.
HOWEVER...THERE ARE PLENTY OF BANDING FEATURES AND WELL-ESTABLISHED
OUTFLOW.  YOU CAN SEE THE CONVECTIVE RING ASSOCIATED WITH THE
EYEWALL ON HIGH RESOLUTION VISIBLE IMAGES.  SUPER RAPID SCAN IR
IMAGES SHOW THE VERY STRONG CONVECTIVE RING CURRENTLY RE-DEVELOPING
AROUND THE EYE. DATA FROM A RECONNAISSANCE PLANE INDICATE THAT THE
SURFACE PRESSURE HAS RISEN TO 934 MB BUT THE FLIGHT LEVEL WINDS
REMAIN AT 144 KNOTS. THIS SUPPORTS AN INITIAL INTENSITY OF 125
KNOTS.  SOME FLUCTUATIONS IN INTENSITY ARE LIKELY BEFORE IVAN MOVES
NEAR OR OVER JAMAICA WHERE THE EFFECTS OF THE HIGH TERRAIN MAY
WEAKEN THE HURRICANE. IT IS POSSIBLE THAT IVAN WILL RE-STRENGTHEN
SOME BETWEEN THE CAYMAN ISLANDS AND CUBA WHERE THE OCEAN IS QUITE
WARM. ONCE IN THE GULF OF MEXICO...THE SHEAR IS FORECAST TO
INCREASE AND IVAN SHOULD GRADUALLY WEAKEN. IVAN IS EXPECTED TO
REMAIN A DANGEROUS HURRICANE UNTIL IT REACHES THE UNITED STATES.

THE HURRICANE IS MOVING TOWARD THE WEST-NORTHWEST OR 300 DEGREES AT
10 KNOTS...STEERED BY THE SUBTROPICAL RIDGE OVER THE BAHAMAS. AS
THE RIDGE WEAKENS...THE STEERING CURRENTS SHOULD WEAKEN TOO...AND
THE HURRICANE WILL LIKELY CONTINUE ON A WEST-NORTHWEST TO NORTHWEST
TRACK WITH A DECREASE IN FORWARD SPEED. THERE IS STILL HIGH
CONFIDENCE IN THIS EARLY PORTION OF THE FORECAST BUT...IT BECOMES
UNCERTAIN AFTER THE HURRICANE CROSSES CUBA WHEN GUIDANCE SHOWS THAT
THE HURRICANE COULD CONTINUE OVER THE GULF OF MEXICO OR COULD TURN
NORTH-NORTHEAST OVER FLORIDA. IN FACT...THIS HAS BEEN THE CASE FOR
THE PAST COUPLE OF DAYS. THE OFFICIAL FORECAST DOES NOT FAVOR ONE
SCENARIO MORE THAN THE OTHER...AND BRINGS THE HURRICANE NORTHWARD
OVER THE GULF OF MEXICO VERY NEAR AND EVENTUALLY OVER FLORIDA.

FORECASTER AVILA

FORECAST POSITIONS AND MAX WINDS

INITIAL      10/1500Z 16.5N  75.1W   125 KT
 12HR VT     11/0000Z 17.2N  76.5W   125 KT
 24HR VT     11/1200Z 18.3N  78.0W   115 KT NEAR JAMAICA
 36HR VT     12/0000Z 19.2N  79.0W   120 KT
 48HR VT     12/1200Z 20.5N  80.2W   125 KT APPROACHING CUBA
 72HR VT     13/1200Z 23.5N  82.0W   110 KT
 96HR VT     14/1200Z 28.0N  83.0W   100 KT
120HR VT     15/1200Z 32.5N  82.5W    40 KT INLAND


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