WDPN31 PGTW 061500 MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 12W (MAN-YI) WARNING NR 20// 1. FOR METEOROLOGISTS. 2. PROGNOSTIC REASONING FOR 061200Z9 TO 091200Z2 AUG 01. A. TYPHOON (TY) 12W (MAN-YI) LOCATED NORTHEAST OF IWO JIMA, HAS TRACKED NORTHEASTWARD AT 04 KNOTS DURING THE PAST SIX HOURS. THE WARNING POSITION IS BASED ON 061130Z1 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON CURRENT SATELLITE INTENSITY ESTIMATES OF 102 TO 115 KNOTS. WATER VAPOR IMAGERY AND UPPER LEVEL ANALYSIS DEPICT THE EXISTENCE OF PRONOUNCED DUAL OUTFLOW CHANNELS ALOFT. THIS PATTERN HAS CONTRIBUTED TO THE INTENSIFICATION OF THE SYSTEM DURING THE PAST 12 HOURS. B. TY 12W IS CURRENTLY WITHIN A WEAKNESS IN THE SUBTROPICAL RIDGE. A MID-LEVEL HIGH IS EXPECTED TO MOVE OUT OF THE SEA OF OKHOTSK BY THE 36 HOUR POINT CREATING A MORE NORTHWARD TRACK THROUGH THE REMAINDER OF THE FORECAST PERIOD. THE GEOPHYSICAL FLUID DYNAMICS-NAVY (GFDN), NOGAPS (NGPS), UKMET GLOBAL GRID-POINT (EGRR), AND JMA GLOBAL (JGSM) AND REGIONAL TYPHOON (JTYM) MODELS, AS WELL AS, THE COAMPS, AND AFWA (MM5) MESOSCALE MODELS, ARE IN GOOD AGREEMENT. THE JMA TYPHOON MODEL, HOWEVER, SHOWS A MORE NORTHWESTWARD TURN AT THE 48 TAU INDICATIVE OF A STRONGER MID-LEVEL RIDGE COMPARED TO THE OTHER MODELS. THE NUMERICAL CONSENSUS CONSISTS OF FIVE MODELS: GFDN, EGRR, NGPS, JGSM, AND JTYM. THE OFFICIAL FORECAST IS A BLEND OF PERSISTENCE AND THE DYNAMIC AIDS CONSENSUS. C. LITTLE CHANGE IN INTENSITY IS FORECAST OVER THE NEXT 12 HOURS. AFTERWARD, THE SYSTEM SHOULD RESTART A SLOW WEAKENING TREND. D. WIND RADII ARE BASED ON MICROWAVE IMAGERY AND CLIMATOLOGY FOR AN AVERAGE-SIZED SYSTEM. E. THE JTWC WEBSITE HAS CHANGED TO: HTTPS://WWW.NPMOC.NAVY.MIL/JTWC.HTML. THIS CHANGE IS FOR SECURITY REASONS ONLY. THE CONTENT OF THE WEBSITE HAS NOT CHANGED. FORECAST TEAM: ROBERTS/BALDINGER/HARRISON//