HOME	ARCHIVES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDEP5 ALL
TTAA00 KNHC DDHHMM
HURRICANE HERNAN DISCUSSION NUMBER  14
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT MON SEP 02 2002
 
HERNAN REMAINS AN IMPRESSIVE HURRICANE DESPITE THE SLOW WEAKENING 
THAT HAS OCCURRED. THE INITIAL INTENSITY OF 110 KT IS BASED DVROAK 
CURRENT INTENSITY ESTIMATES OF 115 KT...T6.0...FROM ALL THREE 
AGENCIES AND THE WARMING EYEWALL CLOUD TOPS.
 
THE INITIAL MOTION ESTIMATE IS 280/10. HERNAN HAS MADE A SLIGHT JOG 
TO THE WEST DURING THE PAST 6 HOURS...BUT THIS IS EXPECTED TO BE A 
TEMPORARY MOTION GIVEN THE INCREASING SOUTHWESTERLY MID- AND 
UPPER-LEVEL FLOW NOTED IN WATER VAPOR IMAGERY WEST OF 125W 
LONGITUDE. ALL OF THE NHC MODEL GUIDANCE REMAINS IN GOOD AGREEMENT 
ON HERNAN GRADUALLY MOVING NORTHWEST BY 36 HOURS AND THEN NORTHWARD 
AND POSSIBLY BEGINNING RECURVATURE TO THE NORTHEAST AFTER 48 HOURS 
AS THE HURRICANE MOVES THROUGH A BREAK IN THE SUBTROPICAL RIDGE. AN 
APPROACHING MID TO UPEPR-LEVEL TROUGH WILL ALSO HELP TO ACCELERATE 
THE SYSTEM TO THE NORTHEAST. THE OFFICIAL TRACK IS CLOSE TO THE AVN 
AND AVN ENSEMBLE MODELS.

HERNAN SHOULD CONTINUE TO WEAKEN THROUGHOUT THE PERIOD AS THE 
CYCLONE MOVES OVER COOLER SSTS AND ENCOUNTERS INCREASING 
SOUTHWESTERLY UPEPR-LEVEL SHEAR. THE OFFICIAL INTENSITY FORECAST 
SHOWS A FASTER WEAKENING TREND THAN THE PREVIOUS FORECAST...BUT NOT 
AS FAST AS THE SHIPS MODEL WHICH BEGINS TO DISSIPATE HERNAN BY 
AROUND 72 HOURS. THE INTENSITY WAS HELD HIGHER THAN SHIPS SINCE 
HERNAN HAS MOVED WESTWARD...WHICH WILL KEEP THE HURRICANE OVER 
WARMER WATER A LITTLE LONGER THAN WHAT SHIPS IS INDICATING.
 
FORECASTER STEWART
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     02/1500Z 18.5N 115.9W   105 KTS
12HR VT     03/0000Z 18.9N 117.5W   100 KTS
24HR VT     03/1200Z 19.7N 119.5W    90 KTS
36HR VT     04/0000Z 20.9N 121.3W    75 KTS
48HR VT     04/1200Z 22.2N 122.8W    60 KTS
72HR VT     05/1200Z 25.0N 124.5W    45 KTS
 
 
NNNN