WDPN31 PGTW 231500
MSGID/GENADMIN/NAVPACMETOCCEN PEARL//JTWC//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON (TY) 12W (FENGSHEN) WARNING/ 
NR 38//
RMKS/
1. FOR METEOROLOGISTS.
2. PROGNOSTIC REASONING FOR 231200Z8 TO 261200Z1 JUL 02.
   A. TYPHOON (TY) 12W (FENGSHEN), LOCATED APPROXIMATELY 135 NM EAST 
OF CHICHI JIMA, HAS TRACKED WEST-NORTHWESTWARD AT 16 KNOTS OVER THE 
PAST SIX HOURS. THE WARNING POSITION IS BASED ON 231130Z0 ENHANCED 
INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 
SATELLITE CURRENT INTENSITY ESTIMATES OF 90 AND 102 KNOTS. A 
231113Z1 SSM/I PASS DEPICTED DEEP CONVECTION CONFINED TO THE NORTH 
QUADRANT WITH THE SOUTH QUADRANT VIRTUALLY CONVECTION FREE. ANALYSIS 
OF THE LOW/MID TROP REVEALS DRY AIR INTRUSION AS THE SOURCE.  
   B. A MID-LEVEL RIDGE SITUATED OVER CENTRAL JAPAN IS FORECAST TO 
STRENGTHEN OVER THE NEXT 24 HOURS BEFORE MOVING OFF OF THE COAST BY 
MID PERIOD. AFTERWARD, A MID LATITUDE LOW AND ASSOCIATED TROUGH IS 
EXPECTED TO MOVE OVER THE RUSSIAN COAST CAUSING THE EXTENSION OF THE 
RIDGE OVER KOREA AND THE SEA OF JAPAN TO WEAKEN SLIGHTLY. AVAILABLE 
NWP (GFDN, AFWA MESOSCALE, UKMETO GLOBAL, AVN, AND THE JMA TYPHOON) 
REFLECT ENOUGH STRENGTH IN THE RIDGE LATE TO CONTINUE THE TROPICAL 
CYCLONE (TC) ON A WEST-NORTHWEST MOTION. NOGAPS, COAMPS AND THE JMA 
GLOBAL INDICATE A MORE PRONOUNCED WEAKNESS. OUR FORECAST IS BASED ON 
A BLEND OF ALL WITH A SLIGHT BIAS TOWARD THE JMA GLOBAL RUN. 
   C. THE TUTT EARLIER SITUATED TO THE NORTHWEST OF 12W, WHICH WAS 
ENHANCING THE POLEWARD OUTFLOW CHANNEL, HAS SINCE DRIFTED SOUTHWEST 
AND IS NOW POSITIONED DUE WEST OF THE TC. THIS HAS CAUSED THE 
OUTFLOW OVER THE NORTH QUADRANT TO DIMINISH CONSIDERABLY. 
ADDITIONALLY, THE SYNOPTIC SCALE UPPER LEVEL RIDGE HAS BEGUN TO RE-
ESTABLISH NORTH OF THE TC. NWP INDICATES THAT THE UPPER EASTERLIES 
ASSOCIATED WITH THE RIDGE WILL STRENGTHEN OVER TY 12W, FURTHER 
SUPPORTING AN UNFAVORABLE ENVIRONMENT. THEREFORE, WE EXPECT THE TC'S 
WEAKENING TREND TO CONTINUE.       
   D. WIND RADII ANALYSIS IS BASED ON MICROWAVE IMAGERY AND QUIKSCAT 
DATA. FORECAST WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE 
SYSTEM. 
3. FORECAST TEAM: ROBERTS/WARREN/RONSSE/EDBERG/SCHAEFER//

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