HOME	ACTIVE CYCLONES	FORECASTS	IMAGERY	ABOUT TPC	RECONNAISSANCE

ZCZC MIATCDEP4 ALL
TTAA00 KNHC DDHHMM
TROPICAL STORM IRWIN DISCUSSION NUMBER   5
NATIONAL WEATHER SERVICE MIAMI FL
2 PM PDT SAT OCT 09 1999
 
THE INITIAL MOTION FROM RADAR AND SATELLITE IMAGERY IS NOW 300/6...
AND IRWIN IS PULLING AWAY FROM THE MEXICAN COAST.  TROPICAL STORM
WARNINGS WERE DISCONTINUED BY THE MEXICAN GOVERNMENT AT 1800Z. 
MODEL GUIDANCE IS A BIT DIVERGENT...WITH THE UKMET AND LBAR GIVING A
WESTWARD TRACK...AND THE NOGAPS AND BAM MODELS SHOWING A
SOUTHWESTERLY MOTION.  THE LATTER SCENARIO IS PROBABLY THE RESULT OF
A FRAUDULENT VORTEX SPIN-UP BEHIND IRWIN.  THE OFFICIAL FORECAST
FOLLOWS THE UKMET AND IS SIMILAR TO...BUT SLIGHTLY FASTER THAN...THE
PREVIOUS ADVISORY.

THE CENTER IS ON THE NORTHEASTERN EDGE OF THE DEEP CONVECTION.  THE
SYSTEM LOOKS A LITTLE BIT MORE VIGOROUS THAN THIS MORNING AND THE
OFFICIAL INTENSITY IS INCREASED TO 50 KT...WITH DVORAK INTENSITY
ESTIMATES OF 55 AND 45 KT FROM TAFB AND SAB RESPECTIVELY.  THE SHIPS
INTENSITY MODEL FORECASTS THAT IRWIN WILL APPROACH HURRICANE
STRENGTH AS THE SHEAR LESSENS OVER THE NEXT 24 HOURS. THE OFFICIAL
FORECAST ALLOWS SOME MODEST INCREASE IN INTENSITY BUT NOT QUITE AS
MUCH AS SHIPS.  AFTER 24-36 HOURS...COOLER TEMPERATURES SHOULD BEGIN
TO LIMIT DEEP CONVECTION AND SPIN DOWN THE VORTEX.
 
FRANKLIN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     09/2100Z 19.1N 107.2W    50 KTS
12HR VT     10/0600Z 19.4N 108.2W    50 KTS
24HR VT     10/1800Z 19.5N 109.4W    55 KTS
36HR VT     11/0600Z 19.5N 111.0W    50 KTS
48HR VT     11/1800Z 19.5N 113.0W    45 KTS
72HR VT     12/1800Z 19.5N 117.0W    35 KTS
 
 
NNNN