WDPN32 PGTW 180300
MSGID/GENADMIN/NAVPACMETOCCEN PEARL HARBOR HI/JTWC// 
SUBJ/PROGNOSTIC REASONING FOR SUPER TYPHOON 19W (PHANFONE) WARNING/
NR 29// 
RMKS/ 
1. FOR METEOROLOGISTS. 
2. PROGNOSTIC REASONING FOR 180000Z9 AUG TO 210000Z3 AUG 02.
   A. TYPHOON (TY) 19W (PHANFONE), LOCATED APPROXIMATELY 330 NM 
SOUTH-SOUTHWEST OF TOKYO, JAPAN HAS TRACKED NORTHWESTWARD AT 05 
KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 
172330Z6 MULTISPECTRAL SATELLITE IMAGERY. THE WARNING INTENSITY 
IS BASED ON SATELLITE CURRENT INTENSITY ESTIMATES OF 90 AND 102 
KNOTS. ENHANCED INFRARED IMAGERY DEPICTS A 43 NM EYE. ANIMATED 
VISIBLE SATELLITE IMAGERY SUGGESTS THE ENTRAINMENT OF DRY AIR IN THE 
WESTERN QUADRANTS.
   B. TY 19W HAS PROPAGATED TO A WEAKNESS IN THE SUBTROPICAL RIDGE 
AND HAS NOW SLOWED ITS ADVANCE. TY 19W WILL NOW BECOME IMPACTED 
INCREASINGLY BY THE MIDLATITUDE WESTERLIES TO TRACK IT TO THE 
NORTHEAST THROUGH THE FORECAST PERIOD. TY19W SHOULD START 
EXTRATROPICAL TRANSITION AFTER 24 HOURS AND SHOULD COMPLETE 
TRANSITION AT 72 HOURS WELL TO THE EAST OF JAPAN. THE AVAILABLE 
DYNAMIC AIDS, CONSISTING OF NCEP AVIATION (AVN), NOGAPS (NGPS), 
UKMET GLOBAL (EGRR), AFWA MM5, COAMPS, GFDN, AND THE JAPANESE GLOBAL 
(JGSM) AND TYPHOON (JTYM) MODELS ARE IN FAIR AGREEMENT WITH THIS 
SCENARIO. THE PRIMARY DIFFERENCE IN THE AIDS IS THE EXTENT OF THE 
INTERACTION WITH THE MID TO HIGH-LEVEL LOW MOVING OVER NORTHERN 
JAPAN. OUR FORECAST IS BASED ON PERSISTENCE AND A BLEND OF ALL THE 
AVAILABLE DYNAMIC MODELS.
   C. TY 19W HAS SHOULD START BEGIN TO WEAKEN WITH THE ENTRAINMENT 
OF DRY AIR OVER THE NEXT 12 TO 18 HOURS. TY 19W WILL THEN CONTINUE 
TO WEAKEN WITH DRY AIR ENTRAINMENT AND INCREASING VERTICAL SHEAR OF 
THE MIDLATITUDE WESTERLIES.  
   D. CURRENT WIND RADII AND FORECASTED WIND RADII ARE BASED ON 
CLIMATOLOGY FOR A LARGE SIZED SYSTEM.
FORECAST TEAM: LEEJOICE/MORRIS/BOSTIC/DUKES//

NNNN