WDPN31 PGTW 071500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 24W (KROSA) WARNING NR 16//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 071200Z0 TO 101200Z4 OCT 01.
   A. TYPHOON (TY) 24W (KROSA), LOCATED APPROXIMATELY 215 NM WEST-
NORTHWEST OF IWO JIMA, HAS TRACKED NORTHEASTWARD AT 11 KNOTS DURING 
THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 071130Z2 
INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 
SATELLITE CURRENT INTENSITY ESTIMATES OF 90 TO 102 KNOTS. ANIMATED 
SATELLITE IMAGERY INDICATES THAT THE SYSTEM HAS WEAKENED SLIGHTLY, 
AND NOW HAS TIGHTLY CURVED BANDS ASSOCIATED WITH THE LOW LEVEL 
CIRCULATION CENTER. ANIMATED WATER VAPOR IMAGERY SHOWS GOOD OUTFLOW 
IN THE NORTHEAST QUADRANT.
   B. TY 24W IS FORECAST TO TRACK GENERALLY NORTHEASTWARD UNDER THE 
STEERING INFLUENCE OF THE MID-LEVEL SUBTROPICAL RIDGE LOCATED TO THE 
EAST. THE AVAILABLE DYNAMIC AIDS OF NOGAPS (NGPS), JMA GLOBAL 
SPECTRAL MODEL (JGSM), JMA TYPHOON MODEL (JTYM), GEOPHYSICAL FLUID 
DYNAMICS-NAVY (GFDN), AND THE UKMET-OFFICE GLOBAL MODEL (EGRR) ARE 
IN GOOD AGREEMENT ON TRACK. HOWEVER, THE GUIDANCE VARIES IN SPEED 
WITH JGSM, JTYM, AND GFDN TRACKING THE SYSTEM VERY SLOWLY 
NORTHEASTWARD, WHICH JTWC ATTRIBUTES TO AN EXCESSIVE INTERACTION 
WITH A MONSOON TROUGH EXTENDING SOUTHWEST INTO THE PHILIPPINE SEA. 
THE OTHER MODELS INDICATE A FASTER ACCELERATION TO THE NORTHEAST. 
DUE TO COMPENSATING ERROR MECHANISMS, THE OFFICIAL FORECAST IS BASED 
ON THE NUMERICAL CONSENSUS CONSISTS OF THE FIVE AFOREMENTIONED 
MODELS. 
   C. TY 24W IS EXPECTED TO SLOWLY WEAKEN AS IT TRACKS INTO 
INCREASING SHEAR AND STRONGER MID-LATITUDE WESTERLIES. 
   D. WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE SIZE 
SYSTEM.
FORECAST TEAM: MAZANY/BALDINGER/JACOBS/PIVIN//