WDPN31 PGTW 180300 
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON (TY) 14W (PABUK) WARNING 
NR 17//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 180000Z9 TO 210000Z3 AUG 01.
   A. TYPHOON (TY) 14W (PABUK), LOCATED APPROXIMATELY 293 NM 
WEST-SOUTHWEST OF THE ISLAND OF IWO JIMA, HAS TRACKED NORTHWESTWARD 
AT 05 KNOTS DURING THE PAST SIX HOURS. THE WARNING POSITION IS BASED 
ON 172330Z6 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS 
BASED ON CURRENT SATELLITE INTENSITY ESTIMATES OF 65 AND 77 KNOTS.  
ANIMATED SATELLITE IMAGERY DEPICTS THE NORTHERN PORTION OF THE EYE-
WALL HAS BEGUN TO REFORM IN THE PAST SIX HOURS. CURRENT ANALYZED 
WIND RADII IS BASED ON A 172017Z8 QUICKSCATT ANALYSIS. 
   B. TY 14W IS CURRENTLY TRACKING NORTHWESTWARD WITHIN EASTERLY 
FLOW ASSOCIATED WITH A WEAKENING LOW TO MID-LEVEL RIDGE NORTH OF THE 
SYSTEM. AN UPPER-LEVEL SHORTWAVE TROUGH OVER EASTERN CHINA IS 
EXPECTED TO MOVE INTO THE EAST CHINA SEA AND DEVELOP A WEAKNESS IN 
THE MID-LEVEL RIDGE OVER WESTERN JAPAN BY 48 HOURS. TY 14W WILL 
RECURVE INTO THIS DEVELOPING WEAKNESS IN THE SUBTROPICAL RIDGE BY 72 
HOURS. THE AVAILABLE DYNAMIC AIDS ARE IN GOOD AGREEMENT AND THE 
SPREAD IN THE DYNAMIC MODEL SOLUTIONS CONTINUES TO DECREASE. THE JMA 
TYPHOON (JTYM) MODEL STILL TRACKS THE SYSTEM NORTHWARD THROUGH THE 
FORECAST PERIOD. THE JMA GLOBAL SPECTRAL (JGSM) MODEL, NATIONAL 
CENTER FOR ENVIRONMENTAL PREDICTION (NCEP) AVIATION MODEL(AVNO), 
GEOPHYSICAL FLUID DYNAMICS MODEL-NAVY (GFDN) AND NOGAPS (NGPS) TRACK 
THE SYSTEM GENERALLY NORTHWESTWARD THROUGH 24 HOURS, THEN NORTHWARD 
THROUGH 48 HOURS FOLLOWED BY A MORE NORTH-NORTHEASTWARD TRACK BY 72 
HOURS. THE UK MET OFFICE GLOBAL (EGRR) MODEL TRACKS THE SYSTEM WEST-
NORTHWESTWARD THROUGH THE 48 HOUR PERIOD AND THEN SHARPLY RECURVES 
NORTHEASTWARD OVER KYUSHU BY 72 HOURS. THE MORE WEST-NORTHWESTWARD 
TRACK OF EGRR CONTINUES TO REFLECT ERRONEOUS INTERACTION WITH A 
CYCLONE IN THE MONSOON TROUGH NEAR LUZON.  THE OFFICIAL FORECAST IS 
BASED ON A CONSENSUS OF ALL AVAILABLE DYNAMIC MODELS WHICH FAVOR 
SLOW RECURVATURE OF TY 14W BY 72 HOURS MAKING LANDFALL IN SOUTH 
CENTRAL JAPAN NEAR THE END OF THE FORECAST PERIOD. THE OFFICIAL 
FORECAST IS BASED ON THE NUMERICAL CONSENSUS OF 5 MODELS (JTYM, 
JGSM, GFDN, NGPS, AND EGRR) BLENDED WITH PERSISTENCE.  
   C. TY 14W IS EXPECTED TO SLOWLY INTENSIFY FOR THE NEXT 24 HOURS 
AS IT REDEVELOPS THE EYEWALL ON THE NORTH SIDE OF THE CYCLONE. ONCE 
A SYMMETRIC EYEWALL HAS RE-ESTABLISHED, A CLIMATOLOGICAL 
INTENSIFICATION IS EXPECTED AS TY 14W TRACKS OVER WARM WATER AND 
MAINTAINS GOOD UPPER-LEVEL OUTFLOW TO THE SOUTH.  TY 14W IS EXPECTED 
TO UNDERGO A BRIEF PERIOD OF RAPID INTENSIFICATION BETWEEN 36 AND 48 
HOURS AS IT MOVES OVER THE WARM KURISHIO CURRENT AND INTO A BREAK IN 
THE UPPER-LEVEL SUBTROPICAL RIDGE.  THIS MORE FAVORABLE UPPER-LEVEL 
ENVIRONMENT IS EXPECTED TO ENHANCE OUTFLOW ALOFT AND AID 
INTENSIFICATION. BY 72 HOURS THE UPPER-LEVEL SHEAR IS EXPECTED TO
INCREASE AND THE SYSTEM WILL BEGIN TO WEAKEN.
   D. FORECAST WIND RADII ARE BASED ON SYNOPTIC REPORTS AND A 
RECENT QUIKSCAT GALE WIND ANALYSIS ADJUSTED FOR CLIMATOLOGY OF A 
LARGE STORM. THE GALE AND STORM WIND RADII WERE EXPANDED AT 171800Z7 
TO REFLECT LARGER WIND RADII ANALYZED ON A 171300Z2 QUICKSCATT AND A 
CMIS 170331Z5 SURFACE ADJUSTED GMS-5 WIND ANALYSIS. A WIND RADII 
ANALYSIS OF THE 172017Z8 QUICKSCATT PASS VERIFIES THE EXPANDED WIND 
RADII. AFTER 48 HOURS THE WIND RADII HAVE BEEN ADJUSTED TO ACCOUNT 
FOR THE DISPLACEMENT OF THE SURFACE WINDS IN RESPONSE TO INCREASED 
UPPER-LEVEL SHEAR AS THE SYSTEM IS EXPECTED TO BEGIN EXTRATROPICAL 
TRANSITION BY 72 HOURS.
FORECAST TEAM: JEFFRIES/HARRISON/CUTMAN//