000
WTNT44 KNHC 062048
TCDAT4
HURRICANE IVAN DISCUSSION NUMBER 18
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 PM EDT MON SEP 06 2004
THE HURRICANE HUNTERS FOUND PEAK FLIGHT LEVEL...700 MB...WINDS OF 94
KT AND 87 KT OVER THE NORTHWEST AND NORTHEAST QUADRANTS
RESPECTIVELY. THIS SUPPORTS A CURRENT INTENSITY OF 90 KT...WHICH IS
CONSISTENT WITH THE MINIMUM CENTRAL PRESSURE THEY MEASURED BY
DROPSONDE...969 MB. THE CENTRAL PRESSURE ESTIMATE FOR THIS ADVISORY
IS SLIGHTLY LOWER SINCE THE DROPSONDE SHOWED WINDS OVER 20 KT WHEN
IT HIT THE SURFACE...SUGGESTING THAT IT WAS NOT IN THE CENTER OF
THE EYE. SATELLITE IMAGES DEPICT A WELL-ORGANIZED HURRICANE...AND
THE UPPER-TROPOSPHERIC OUTFLOW REMAINS IMPRESSIVE. WE SEE NO
REASON WHY IVAN COULD NOT RESTRENGTHEN VERY SOON...AND THIS IS
REFLECTED IN THE OFFICIAL FORECAST.
INITIAL MOTION...285/19...IS NOT MUCH DIFFERENT FROM WHAT IT WAS
EARLIER TODAY. THE HURRICANE SHOULD CONTINUE TO BE STEERED
WEST-NORTHWESTWARD BY A STRONG EASTERLY TO EAST-SOUTHEASTERLY
CURRENT FOR THE NEXT FEW DAYS. THE DYNAMICAL TRACK MODEL
CONSENSUS...CONU...HAS BEEN SHIFTING A LITTLE TO THE WEST
TODAY...SO THE OFFICIAL FORECAST IS ALSO SHIFTED A LITTLE TO THE
LEFT OF THE PREVIOUS ONE. HOWEVER...IN THE 4-5 DAY TIME
FRAME...THERE IS A LOT OF UNCERTAINTY AS TO HOW MUCH MID-LEVEL
RIDGING WILL DEVELOP BETWEEN FRANCES...OR ITS REMNANTS OVER THE
EAST-CENTRAL UNITED STATES...AND IVAN. IF A SIGNIFICANT WEAKNESS
IS LEFT IN THE VICINITY OF FLORIDA...IVAN COULD VEER TOWARD THE
BAHAMAS NEAR THE END OF THE FORECAST PERIOD. IT IS SIMPLY TOO
EARLY TO BE MORE SPECIFIC REGARDING THE POTENTIAL THREAT TO THE
UNITED STATES COAST.
BASED ON THE AIRCRAFT DATA...THE WIND RADII HAVE BEEN ADJUSTED TO
SHOW A MORE ASYMMETRIC CIRCULATION.
FORECASTER PASCH
FORECAST POSITIONS AND MAX WINDS
INITIAL 06/2100Z 11.6N 55.3W 90 KT
12HR VT 07/0600Z 12.3N 58.1W 100 KT
24HR VT 07/1800Z 13.2N 61.5W 105 KT
36HR VT 08/0600Z 14.0N 64.4W 110 KT
48HR VT 08/1800Z 15.0N 67.4W 115 KT
72HR VT 09/1800Z 17.5N 72.5W 120 KT
96HR VT 10/1800Z 20.0N 76.5W 80 KT...INLAND
120HR VT 11/1800Z 23.0N 80.0W 75 KT...INLAND
$$
