WDPN32 PGTW 021500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W (MAWAR) WARNING NR 
08//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
TROPICAL STORM 18W (MAWAR), LOCATED APPROXIMATELY 178 NM EAST-
SOUTHEAST OF HONG KONG, HAS TRACKED NORTHWARD AT 03 KNOTS OVER
THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY SHOWS 
PERSISTENT CONVECTION WRAPPING INTO A BROAD BUT CONSOLIDATING LOW 
LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH 
HIGH CONFIDENCE BASED ON A 021257Z METOP-B ASCAT IMAGE SHOWING A 
CONCISE LLCC. THE INITIAL INTENSITY OF 45 KNOTS IS BASED ON 
MULTIAGENCY DVORAK INTENSITY ESTIMATES OF T3.0 (45 KNOTS) AND IS 
SUPPORTED BY THE AFOREMENTIONED ASCAT IMAGE. ENVIRONMENTAL ANALYSIS 
INDICATES THAT GOOD EQUATORWARD OUTFLOW AND WARM (29 CELSIUS) SEA 
SURFACE TEMPERATURES ARE BEING OFFSET BY HIGH (25-30 KNOTS) VERTICAL 
WIND SHEAR (VWS). TS MAWAR IS CURRENTLY TRACKING SLOWLY NORTH-
NORTHWESTWARD ALONG THE WESTERN EDGE OF AN EXTENSION OF THE 
SUBTROPICAL RIDGE (STR) BUILDING IN THE PHILIPPINE SEA.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST TRACK PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.   
   B. TS MAWAR IS FORECAST TO TRACK TO THE NORTH-NORTHWEST FOR THE 
DURATION OF THE FORECAST. THE STEERING STR IS ALSO TRANSITING SLOWLY 
TO THE NORTHWEST AND WILL REMAIN THE DOMINANT STEERING FEATURE 
THROUGHOUT THE FORECAST. THE SYSTEM WILL MAKE LANDFALL SHORTLY AFTER 
TAU 24, EAST OF HONG KONG. MARGINALLY FAVORABLE ENVIRONMENTAL 
CONDITIONS WILL PERSIST ALONG THE TRACK WITH HIGH VWS PREVENTING 
EXTENSIVE INTENSIFICATION. THE SYSTEM WILL REACH A PEAK INTENSITY OF 
50 KNOTS PRIOR TO LANDFALL. AFTER LANDFALL, TS 18W WILL RAPIDLY 
DISSIPATE DUE TO THE FRICTION EFFECTS OF INTERACTION WITH THE RUGGED 
TERRAIN OF SOUTHEASTERN CHINA. THE SYSTEM WILL FULLY DISSIPATE BY 
TAU 48. DYNAMIC MODEL GUIDANCE IS IN GENERAL AGREEMENT WITH THE 
TRACK DIRECTION, HOWEVER THE MODELS DIVERGE SIGNIFICANTLY BOTH PRIOR 
TO AND AFTER LANDFALL. DUE TO THE SPREAD IN MODEL GUIDANCE, THERE IS 
LOW CONFIDENCE IN THE JTWC TRACK FORECAST.//
NNNN