WDPN31 PGTW 151500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (MAN-YI) WARNING NR 
12//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 16W (MAN-YI), LOCATED APPROXIMATELY 400 NM 
SOUTHWEST OF YOKOSUKA, JAPAN, HAS TRACKED NORTHWARD AT 15 KNOTS OVER 
THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY DEPICTS 
A SMALL CENTRAL DENSE OVERCAST FEATURE OBSCURING THE CENTER OF A 
CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC). IR IMAGERY ALSO 
SHOWS A DEEP CONVECTIVE BAND OVER THE WESTERN SEMI-CIRCLE WRAPPING 
INTO THE SOUTH QUADRANT OF THE LLCC. A 151006Z SSMIS IMAGE SHOWS A 
WEAK MICROWAVE EYE FEATURE, WHICH, ALONG WITH RJTD RADAR FIXES, 
SUPPORTS THE INITIAL POSITION WITH GOOD CONFIDENCE. A 151125Z 
PARTIAL ASCAT IMAGE SHOWS AN EXTENSIVE AREA OF 35 TO 45 KNOT WINDS 
OVER THE EASTERN SEMI-CIRCLE OF THE SYSTEM, INDICATIVE OF THE LARGE 
SIZE OF THE SYSTEM (APPROXIMATELY 600 NM DIAMETER). THE INITIAL 
INTENSITY IS ASSESSED AT 60 KNOTS BASED ON AN AVERAGE OF DVORAK 
ESTIMATES WHICH RANGE FROM 55 TO 65 KNOTS. ANIMATED WATER VAPOR 
IMAGERY INDICATES IMPROVED POLEWARD VENTING AHEAD OF AN UPPER-LEVEL 
SHORTWAVE TROUGH, WHICH IS DIGGING INTO KOREA AND WESTERN JAPAN. 
CONSEQUENTLY, CORE CONVECTION HAS IMPROVED MARKEDLY AND THE SYSTEM 
HAS INTENSIFIED. ALTHOUGH VERTICAL WIND SHEAR (VWS) HAS INCREASED TO 
30 TO 35 KNOTS, TS 16W IS CURRENTLY TRACKING PARALLEL TO THE 
SOUTHERLY SHEAR VECTOR, WHICH IS EFFECTIVELY REDUCING THE IMPACT OF 
THE STRONG VWS AND ALLOWING FOR FURTHER INTENSIFICATION. TS 16W IS 
ACCELERATING ALONG THE NORTHWESTERN PERIPHERY OF THE SUBTROPICAL 
RIDGE (STR).
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS 16W HAS TURNED NORTH-NORTHEASTWARD AND IS FORECAST TO 
ACCELERATE NORTHEASTWARD TOWARD CENTRAL JAPAN AS IT BEGINS EXTRA-
TROPICAL TRANSITION (ETT). AS DEPICTED IN MODEL FIELDS, THE SYSTEM 
SHOULD COMPLETE ETT BY TAU 24 AS IT BECOMES EMBEDDED WITHIN THE 
MIDLATITUDE WESTERLIES NEAR OR TO THE EAST OF THE KANTO PLAIN WITH A 
CLEAR FRONTAL SIGNATURE SHOWN IN THE 1000-500MB THICKNESS FIELDS. 
OVERALL, THERE IS HIGH CONFIDENCE IN THE TRACK SCENARIO AND THE JTWC 
FORECAST TRACK BASED ON THE TIGHT CLUSTER OF DYNAMIC GUIDANCE WITH 
THE EXCEPTION OF GFDN, WHICH HAS REMAINED HIGHLY ERRATIC AND IS THE 
SOLE OUTLIER. AT 16/03Z (CPA TO TOKYO), THERE IS ONLY A 65 NM SPREAD 
IN SOLUTIONS. THE PEAK INTENSITY REMAINS SET AT 60 KNOTS; HOWEVER, 
THE SYSTEM COULD STRENGTHEN TO 65 KNOTS WITHIN THE NEXT SIX HOURS, 
PRIOR TO LANDFALL, DUE TO FAVORABLE POLEWARD OUTFLOW. AFTER TAU 12, 
THE SYSTEM WILL WEAKEN AS IT TRACKS OVER LAND AND ENCOUNTERS 
INCREASING VERTICAL WIND SHEAR. THE SYSTEM IS EXPECTED TO MAINTAIN 
50 TO 55 KNOT SUSTAINED WINDS AS IT TRACKS ACROSS THE KANTO PLAIN 
AND SHOULD ALSO MAINTAIN EXPANSIVE GALE FORCE WINDS AS IT TRACKS 
BACK OVER WATER.//
NNNN