MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 26W (TWENTYSIX) WARNING NR 02// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION (TD) 26W (TWENTYSIX), LOCATED APPROXIMATELY 1038 NM EAST OF SAIPAN, CNMI, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM MAINTAINED OVERALL CONVECTIVE STRUCTURE AS IT CONTINUES TO CONSOLIDATE. THE INITIAL POSITION IS PLACED WITH GOOD CONFIDENCE BASED ON A RAGGED AND PARTLY OBSCURED LOW LEVEL CIRCULATION FEATURE IN THE 111624Z SSMI 36GHZ COLORIZED IMAGE. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON THE DVORAK ESTIMATES OF T1.5/25KTS FROM PGTW AND RJTD. BASED ON ANALYSES, THE ENVIRONMENT IS OVERALL FAVORABLE FOR DEVELOPMENT WITH LIGHT TO MODERATE (10-20KT) VERTICAL WIND SHEAR (VWS), FAIR EQUATORWARD OUTFLOW, AND WARM (29C) ALONG-TRACK SST VALUES. THE CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 26W WILL CONTINUE IN ITS CURRENT TRACK UNDER THE STR UP TO TAU 72. THE OVERALL FAVORABLE ENVIRONMENT WILL ENHANCE A GRADUAL INTENSIFICATION, REACHING 75KTS BY TAU 72. NUMERICAL MODELS ARE IN TIGHT AGREEMENT, LENDING HIGH CONFIDENCE TO THIS PORTION OF THE JTWC TRACK FORECAST. C. AFTER TAU 72, TD 26W WILL TURN MORE NORTHWARD AS THE STR WEAKENS IN RESPONSE TO A MID-LATITUDE TROUGH APPROACHING FROM THE NORTHWEST, CREST THE STR AXIS, AND ACCELERATE NORTHEASTWARD ON THE POLEWARD SIDE OF THE STR. STRONG JET WINDS AHEAD OF THE TROUGH WILL INTRODUCE A VIGOROUS POLEWARD OUTFLOW AND BRING THE SYSTEM TO A PEAK OF 85KTS BY TAU 96. AFTERWARD, INCREASING VWS AND COOLING SSTS WILL BEGIN TO ERODE THE SYSTEM. CONCURRENTLY, TD 26W WILL BEGIN EXTRA- TROPICAL TRANSITION AS IT APPROACHES THE COLD BAROCLINIC ZONE. NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH SPREADING TO 240NM BY TAU 120; HOWEVER, THERE ARE DISTINCT DIFFERENCES IN THE ALONG-TRACK SPEED ESPECIALLY DURING THE RECURVE NORTHEASTWARD. THEREFORE, THERE IS LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC TRACK FORECAST.// NNNN NNNN