WDPN31 PGTW 100300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (DANAS) WARNING 
NR 29//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 100000Z1 TO 130000Z4 SEP 01.
   A. TYPHOON (TY) 19W (DANAS), LOCATED APPROXIMATELY 210 NM SOUTH-
SOUTHWEST OF TOKYO, HAS TRACKED NORTH-NORTHWESTWARD AT 7 KNOTS 
DURING THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 092330Z7 
VISIBLE AND INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS 
BASED ON CURRENT SATELLITE INTENSITY ESTIMATES OF 77 AND 90 KNOTS.
ANIMATED VISIBLE SATELLITE IMAGERY DEPICTS A BANDING EYE. ANIMATED 
WATER VAPOR SATELLITE IMAGERY REVEALS THE UPSTREAM TROUGH BEGINNING 
TO INTERACT WITH THE SYSTEM.
   B. TY 19W IS UNDER THE STEERING INFLUENCE OF THE MID-LEVEL 
SUBTROPICAL RIDGE EAST-NORTHEAST OF THE SYSTEM. THE SYSTEM HAS BEGUN 
TO MOVE MORE NORTH-NORTHWESTWARD AS THE APPROACH OF THE MID-
LATITUDE TROUGH FROM THE WEST HAS WEAKENED THE RIDGE THAT HAS BEEN 
PRESENT NORTH OF THE SYSTEM. AFTER THE 12 HOUR POINT TY 19W WILL BE 
NORTH OF THE SUBTROPICAL RIDGE AXIS AND BEGIN RECURVING TO THE 
NORTHEAST. EXTRATROPICAL TRANSITION WILL BEGIN AT THE 36 HOUR POINT 
AS IT INTERACTS WITH THE BAROCLINIC ZONE. THE 5 MODEL DYNAMIC AIDS 
CONSENSUS CONSISTING OF NOGAPS (NGPS), THE GEOPHYSICAL FLUID 
DYNAMICS-NAVY (GFDN) MODEL, THE UK-MET OFFICE (EGRR) MODEL, JMA 
TYPHOON (JTYM) AND GLOBAL SPECTRAL (JGSM) MODELS ARE IN GOOD 
AGREEMENT THROUGH THE FIRST 48 HOURS. AFTER THIS POINT JGSM AND JTYM 
INDICATE A SLOWER SPEED OF ADVANCE WITH NOGAPS, GFDN AND EGRR 
TRACKING THE SYSTEM MORE RAPIDLY TO THE NORTHEAST AS THE SYSTEM 
BECOMES EXTRATROPICAL. THE OFFICIAL FORECAST IS BASED ON THE 
NUMERICAL CONSENSUS OF FIVE MODELS.  
   C. TY 19W IS EXPECTED TO MAINTAIN INTENSITY UNTIL LANDFALL AT THE 
12 HOUR FORECAST POSITION, AND THEN WILL WEAKEN RAPIDLY AS IT 
INTERACTS WITH LAND THROUGH THE REMAINDER OF THE FORECAST. 
   D. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE 
SIZE SYSTEM AND A RECENT QUIKSCAT GALE WIND ANALYSIS. 
FORECAST TEAM: CANTRELL/VILPORS/WAUGAMAN/SHERRY//