WDPN31 PGTW 160300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (MAN-YI) WARNING NR 
14//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 16W (MAN-YI), LOCATED APPROXIMATELY 88 NM WEST
OF YOKOSUKA, JAPAN, HAS TRACKED NORTHEASTWARD AT 29 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) 
DEPICTS A CENTRAL DENSE OVERCAST (CDO) FEATURE OVERHEAD OF A 
CONSOLIDATED LOW-LEVEL CIRCULATION CENTER (LLCC) THAT IS CURRENTLY 
TRACKING OVER SOUTHEAST JAPAN. THE MSI SHOWS A DEEP CONVECTIVE BAND 
OVER THE WESTERN SEMI-CIRCLE WRAPPING INTO THE SOUTH QUADRANT OF THE 
LLCC. A 152143Z SSMIS MICROWAVE IMAGE FURTHER REVEALS THE STRONG 
STRUCTURE OF THE BANDING AS WELL AS THE DEEP CONVECTION MAKING UP 
THE CDO FEATURE. THE INITIAL POSITION IS BASED ON THE MSI LOOP, THE 
AFOREMENTIONED MICROWAVE IMAGERY, AS WELL AS RJTD RADAR FIXES WITH 
HIGH CONFIDENCE. TS 16W HAS MAINTAINED A LARGE SIZE (APPROXIMATELY 
600 NM DIAMETER) EVEN AFTER TRACKING OVERLAND AND CONTINUES TO 
EXHIBIT AN EXTENSIVE AREA OF 35 TO 45 KNOT WINDS OVER THE EASTERN 
SEMI-CIRCLE OF THE SYSTEM. THE INITIAL INTENSITY IS HELD AT 60 KNOTS 
BASED ON A DVORAK INTENSITY ESTIMATE OF 55 KNOTS FROM RJTD AND THE 
WELL MAINTAINED STRUCTURE OVER THE PAST SIX HOURS. ANIMATED WATER 
VAPOR IMAGERY CONTINUES TO INDICATE GOOD POLEWARD VENTING AHEAD OF 
AN UPPER-LEVEL SHORTWAVE TROUGH, WHICH IS DIGGING INTO KOREA AND 
WESTERN JAPAN. CORE CONVECTION HAS MAINTAINED OVER THE PAST SIX 
HOURS AND THE OVERALL STRUCTURE APPEARS TO BE STRONG DESPITE THE 
SYSTEM TRACKING OVER LAND. ALTHOUGH VERTICAL WIND SHEAR (VWS) IS 
ASSESSED AT 30 TO 40 KNOTS, TS 16W IS CURRENTLY TRACKING PARALLEL TO 
THE SOUTHERLY SHEAR VECTOR, WHICH IS EFFECTIVELY REDUCING THE IMPACT 
OF THE STRONG VWS AND ALLOWING THE SYSTEM TO MAINTAIN ORGANIZATION. 
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 IS TRACKING NORTHEASTWARD AND IS FORECAST TO CONTINUE 
ACCELERATING NORTHEASTWARD THROUGH CENTRAL JAPAN AS IT BEGINS EXTRA-
TROPICAL TRANSITION (ETT). MODEL FIELDS INDICATE THE SYSTEM SHOULD 
COMPLETE ETT BY TAU 12 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. AT 16/02Z (CPA 
TO YOKOSUKA), THERE IS ONLY A 30 NM SPREAD IN SOLUTIONS. THE PEAK 
INTENSITY REMAINS SET AT 60 KNOTS DUE TO THE MAINTAINED ORGANIZATION 
OVER LAND AND THE FAVORABLE POLEWARD OUTFLOW. AS TS 16W CONTINUES TO 
TRACK OVER LAND THE SYSTEM WILL SLIGHTLY WEAKEN DUE TO FRICTIONAL 
EFFECTS AS WELL AS INCREASING VERTICAL WIND SHEAR. DESPITE THIS, 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 AS AN EXTRA-TROPICAL 
SYSTEM.//
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