MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 18W (MALAKAS) WARNING NR 30// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 18W (MALAKAS), LOCATED APPROXIMATELY 262 NM SOUTH- SOUTHWEST OF SASEBO, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION IS BASED ON SATELLITE EYE FIXES FROM RJTD AND PGTW WITH HIGH CONFIDENCE. THE INTENSITY OF 105 KNOTS IS CONSISTENT WITH SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM THE SAME REPORTING AGENCIES, AS WELL AS RECENT OBJECTIVE SATELLITE INTENSITY CONSENSUS ESTIMATES FROM CIMSS. TY 18W HAS MAINTAINED INTENSITY OVER THE PAST SIX HOURS WHILE TRACKING NORTHEASTWARD ALONG THE NORTHWESTERN PERIPHERY OF A SUBTROPICAL STEERING RIDGE. RECENT MULTISPECTRAL SATELLITE IMAGERY SHOWS THE PRESENCE OF A 12 NM DIAMETER EYE. STRONG POLEWARD OUTFLOW AND PASSAGE OVER WARM WATER HAVE ENABLED TY 18W TO MAINTAIN INTENSITY OVER THE PAST SIX HOURS. ALTHOUGH THE SYSTEM HAS BEGUN TO ENCOUNTER STRONG UPPER-LEVEL WESTERLY FLOW, STORM MOTION IN PHASE WITH THE SHEAR VECTOR HAS PREVENTED NEGATIVE IMPACTS TO THE CIRCULATION THUS FAR. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 18W WILL ACCELERATE NORTHEASTWARD ALONG THE POLEWARD PERIPHERY OF THE CURRENT STEERING RIDGE THROUGH THE FORECAST PERIOD. INTENSITY IS EXPECTED TO REMAIN FAIRLY STEADY OVER THE NEXT 12 HOURS AS STRONG POLEWARD OUTFLOW CONTINUES TO COUNTERACT THE POTENTIALLY NEGATIVE IMPACT OF INCREASING WESTERLY FLOW ALOFT. HOWEVER, INCREASING VERTICAL WIND SHEAR AND PASSAGE OVER LAND AFTER TAU 12 WILL LEAD TO RAPID WEAKENING. THE SYSTEM WILL BEGIN EXTRATROPICAL TRANSITION AROUND TAU 36 AS IT PASSES ALONG THE SOUTHERN COAST OF HONSHU. HOWEVER, TY 18W IS EXPECTED TO DISSIPATE BELOW THE WARNING THRESHOLD INTENSITY OF 25 KNOTS AS IT COMPLETES EXTRATROPICAL TRANSITION AROUND TAU 72. NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT REGARDING THE FORECAST TRACK, WITH THE EXCEPTION OF THE JAPANESE ENSEMBLE TRACKER, JENI, WHICH DEPICTS A TRACK ACROSS HONSHU AND INTO THE SEA OF JAPAN, AND HWRF, WHICH DEPICTS A TRACK INTO CENTRAL HONSHU AND INLAND DISSIPATION. THE CURRENT FORECAST FAVORS THE MAJORITY TRACK GROUPING, AND LIES NEAR THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE.// NNNN NNNN