MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TYPHOON 11W (NANGKA) WARNING NR 15// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TYPHOON 11W (NANGKA), LOCATED APPROXIMATELY 585 NM EAST-SOUTHEAST OF SAIPAN, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A WELL DEVELOPED SYSTEM WITH A 15 NM EYE AND ROBUST OUTFLOW. A 062044Z SSMIS MICROWAVE IMAGE REVEALS A SOLID EYEWALL WITH FORMATIVE CONVECTIVE BANDS WRAPPING INTO THE SYSTEM. THE INITIAL POSITION IS BASED ON THE MSI ANIMATION AND AFOREMENTIONED MICROWAVE IMAGE WITH HIGH CONFIDENCE. THE INTENSITY HAS BEEN ASSESSED AT 95 KNOTS BASED ON AN AVERAGE OF DVORAK INTENSITY ESTIMATES FROM PGTW AND RJTD. UPPER LEVEL ANALYSIS INDICATES AN ENVIRONMENT CHARACTERIZED BY RADIAL OUTFLOW AND 10-20 KNOT NORTHWESTERLY VERTICAL WIND SHEAR. TY 11W IS CURRENTLY TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TY 11W WILL CONTINUE TRACKING TO THE NORTHWEST UNDER THE EXTENSION OF THE STR THROUGH TAU 72. THE UPPER LEVEL ENVIRONMENT WILL REMAIN FAVORABLE OVER THE NEXT 72 HOURS WITH NANGKA FORECASTED TO PEAK AT 130 KNOTS BY TAU 48 AND MAINTAIN THROUGH TAU 72. C. IN THE EXTENDED TAUS, TY 11W WILL BEGIN TO SLOW AS AN APPROACHING MID-LATITUDE TROUGH WEAKENS THE EXTENSION OF THE STR CREATING A WEAK STEERING ENVIRONMENT AND ALLOWING THE SYSTEM TO BEGIN MOVING POLEWARD. ALTHOUGH NANGKA WILL HAVE GOOD POLEWARD OUTFLOW, SSTS AND OHC VALUES DECREASE POLEWARD OF 19N AND VWS SHEAR WILL BEGIN TO INCREASE AS WELL. DYNAMIC MODEL GUIDANCE HAS COME INTO TIGHTER AGREEMENT CONCERNING THE TIMING AND OVERALL EFFECT OF THE MID-LATITUDE TROUGH BREAKING DOWN THE STR IN THE EXTENDED TAUS. COMBINED WITH THE CLOSE AGREEMENT IN THE GUIDANCE THROUGH TAU 72, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS AND HEDGED SLIGHTLY CLOSER TO THE GFS AND ECMWF SOLUTIONS.// NNNN NNNN