WDPN31 PGTW 180900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 23W (TWENTYTHREE) WARNING NR 03// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL STORM 23W (TWENTYTHREE), LOCATED APPROXIMATELY 401 NM NORTH OF OROLUK, HAS TRACKED NORTHWESTWARD AT 08 KNOTS OVER THE PAST SIX HOURS. THE INITIAL POSITION IS PLACED WITH LOW CONFIDENCE USING ANIMATED MULTISPECTRAL SATELLITE IMAGERY THAT SHOWS FLARING CONVECTION THAT IS PARTIALLY OBSCURING, BUT ROTATING AROUND, THE LOW LEVEL CIRCULATION CENTER (LLCC). THE CURRENT INTENSITY IS ASSESSED AT 35 KNOTS, CONSISTENT WITH THE PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.5 (35 KTS), BUT SLIGHTLY ABOVE THE KNES AND RJTD DVORAK INTENSITIES OF T2.0 (30 KTS). THE ENVIRONMENT IS MARGINALLY FAVORABLE FOR INTENSIFICATION WITH HIGH VERTICAL WIND SHEAR, NO POLEWARD OUTFLOW, AND GOOD EQUATORWARD OUTFLOW. WARM SEA SURFACE TEMPERATURE (29-30 C) SUPPORTS INTENSIFICATION. TS 23W IS TRACKING WEST-NORTHWESTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. 3. FORECAST REASONING. A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY FROM THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TS 23W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE STR RIDGE THROUGH TAU 72. OUTFLOW FROM TY 22W WILL CONTINUE TO BRING NORTHWESTERLY VWS AND HAMPER INTENSIFICATION. MODELS ARE IN GOOD AGREEMENT ON STORM MOTION, WITH 170 NM OF SPREAD AT TAU 72. THE JTWC FORECAST INTENSITY CLOSELY FOLLOWS THE MESOSCALE MODEL INTENSITY GUIDANCE. THE JTWC FORECAST TRACK IS PLACED CLOSED TO THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE. C. THE FORECAST TRACK WILL SHIFT SLIGHTLY MORE NORTHWARD BY TAU 120 AS AN APPROACHING MID-LATITUDE TROUGH WILL WEAKEN THE RIDGE NEAR THE END OF THE PERIOD. THE TRACK GUIDANCE REMAINS IN GOOD AGREEMENT WITH 275 NM IN SPREAD BY TAU 120. THE INTENSITY IS EXPECTED TO CLIMB AT THE CLIMATOLOGICAL RATE, AS DEPICTED BY THE MESOSCALE MODEL GUIDANCE, TO A PEAK OF 95 KTS BY THE END OF THE FORECAST PERIOD. THE JTWC FORECAST TRACK IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS WITH GOOD CONFIDENCE.// NNNN