MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 01W (MEKKHALA) WARNING NR 16// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 01W (MEKKHALA), LOCATED APPROXIMATELY 316 NM EAST- SOUTHEAST OF MANILA, PHILIPPINES, HAS TRACKED NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE SYSTEM HAS MAINTAINED A CENTRAL DENSE OVERCAST FEATURE THAT CONTINUES TO OBSCURE THE LOW LEVEL CIRCULATION CENTER. THE INITIAL POSITION JUST EAST OF SAMAR IS BASED ON THE MSI LOOP AND A 170523Z N-19 89 GHZ MICROWAVE IMAGE WITH GOOD CONFIDENCE. THE INITIAL INTENSITY OF 70 KNOTS IS MAINTAINED DUE TO DVORAK ESTIMATES FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS DEPICTS A FAVORABLE ENVIRONMENT WITH MODERATE (10 TO 20 KNOTS) EASTERLY VERTICAL WIND SHEAR IN-PHASE WITH THE SYSTEM MOTION AND GOOD RADIAL OUTFLOW. THE CYCLONE IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF AN ELONGATED SUBTROPICAL RIDGE (STR). 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY MEKKHALA WILL TRACK TO THE NORTHWEST UNDER THE INFLUENCE OF THE STR. AS THE SYSTEM MAKES LANDFALL, EXPECT THE TERRAIN OF EASTERN PHILIPPINES TO CAUSE TY 01W TO BEGIN TO DISSIPATE. EXPECT THIS DECAY TO OCCUR AS THE SYSTEM TRACKS THROUGH THE BICOL REGION AND THEN SOUTH OF CALABARZON, WITH THE SYSTEM LESS THAN STORM FORCE STRENGTH BY THE TIME IT REACHES MANILA. TY MEKKHALA WILL BE COMPLETELY DISSIPATED AS IT RE-EMERGES IN THE SOUTH CHINA SEA BY TAU 72. THERE REMAINS TO BE A LARGE SPREAD IN DYNAMIC MODEL GUIDANCE WHICH LEADS TO LOW CONFIDENCE IN THE JTWC FORECAST TRACK.// NNNN NNNN