WDPN31 PGTW 110900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 16W (CHAN-HOM) WARNING NR 027// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM (TS) 16W (CHAN-HOM), LOCATED APPROXIMATELY 227 NM SOUTH-SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED EAST- SOUTHEASTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY REVEALS AN EXPOSED, DEFINED LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION DISPLACED TO THE NORTHEAST. AN 110701Z SSMIS 91GHZ MICROWAVE IMAGE DEPICTS SHALLOW BANDING WRAPPING TIGHTLY INTO THE DEFINED LLCC WITH DISORGANIZED DEEP CONVECTION OVER THE EASTERN SEMICIRCLE. THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS BASED ON DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM 2.5-3.0 (35-45 KNOTS). TS 16W IS LOCATED WITHIN A MARGINAL ENVIRONMENT AND IS TRACKING EQUATORWARD UNDER THE BACK EDGE OF AN UPPER-LEVEL SHORTWAVE TROUGH WITH STRONG (30-35 KNOTS) VERTICAL WIND SHEAR (VWS). ADDITIONALLY, THERE IS SIGNIFICANT DRY AIR ENTRAINING INTO THE SYSTEM. TS 16W APPEARS TO BE A HYBRID/SUBTROPICAL SYSTEM WITH AN ASYMMETRIC APPEARANCE IN THE TOTAL PRECIPITABLE WATER IMAGERY AND MODERATE BAROCLINICITY. THE SYSTEM IS TRACKING ALONG THE NORTHEASTERN PERIPHERY OF A LOW-LEVEL SUBTROPICAL RIDGE POSITIONED TO THE SOUTHWEST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 16W IS EXPECTED TO TURN SOUTH-SOUTHEASTWARD AS IT TRACKS ALONG THE EASTERN PERIPHERY OF THE LOW-LEVEL STR THROUGH THE FORECAST PERIOD. TS 16W WILL WEAKEN STEADILY DUE TO STRONG (>30 KT) VWS AND CONTINUED DRY AIR ENTRAINMENT WITH DISSIPATION ANTICIPATED BY TAU 36. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 36 BUT DIVERGES AFTER TAU 36. OVERALL, THERE IS FAIR CONFIDENCE IN THE JTWC FORECAST TRACK. AFTER TAU 72, AS THE SYSTEM TRACKS OVER WARM SST (28-29C) AND UNDER DECREASING VWS (<20 KNOTS), THERE IS SOME POTENTIAL FOR IT TO SLOWLY REGENERATE AS A WARM-CORE TROPICAL SYSTEM.// NNNN