MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 34W (MAN-YI) WARNING NR 17// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON (TY) 34W (MAN-YI), LOCATED APPROXIMATELY 677 NM SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED NORTHWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS COMPACTED RAIN BANDS WRAPPING INTO A BROAD DEEP CENTRAL CONVECTION THAT IS OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS BASED ON A DEFINED MICROWAVE EYE IN THE COLOR-ENHANCED 231741Z GPM 36GHZ IMAGE WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 90 KNOTS BASED ON EQUIVALENT DVORAK INTENSITY ESTIMATES OF T5.0/90KTS FROM PGTW, KNES, AND RJTD AND REFLECTS THE SLIGHTLY IMPROVED EIR SIGNATURE OF THE SYSTEM. UPPER-LEVEL ANALYSIS INDICATES LOW VERTICAL WIND SHEAR AND EXCELLENT POLEWARD OUTFLOW ENHANCED BY STRONG WESTERLIES TO THE NORTH. THE CYCLONE IS TRACKING ALONG THE WESTERN PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 34W IS FORECAST TO SLOW DOWN AND CONTINUE TRACKING NORTHWARD THROUGH TAU 12. AFTERWARD, IT WILL PICK UP SPEED AND TURN NORTHWEST-WARD THROUGH TAU 72 AS A BROAD HIGH PRESSURE SYSTEM BUILDS TO THE NORTH. LOW-LEVEL NORTHEASTERLY FLOW ASSOCIATED WITH THIS HIGH IS FORECAST TO BRING IN DRY AND COOLER AIR WHICH WILL RESULT IN A RAPID WEAKENING TREND - DOWN TO 40 KNOTS BY TAU 72. THERE IS AN OVERALL AGREEMENT AMONG THE NUMERICAL MODEL GUIDANCE MEMBERS WITH THE SHAPE OF THE FORECAST TRACK BUT WITH LARGE DIFFERENCES IN SPAN AND TIMING, LENDING LOW CONFIDENCE IN THIS PORTION OF THE JTWC TRACK FORECAST THAT IS LAID CLOSE TO THE MODEL CONSENSUS. C. AFTER TAU 72, TY MAN-YI WILL ACCELERATE NORTHEASTWARD ALONG THE NORTHWEST PERIPHERY OF THE NEW STR. THE AFOREMENTIONED ADVERSE CONDITIONS WILL PREVAIL. THIS, IN ADDITION TO INCREASING VWS AND COOLING SSTS, WILL RESULT IN DISSIPATION BY TAU 120. NUMERICAL MODEL GUIDANCE CONTINUES TO DIVERGE SIGNIFICANTLY, REACHING A SPAN OF OVER 500NM BY TAU 120, LENDING LOW CONFIDENCE TO THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.// NNNN NNNN