MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 02W (SANBA) WARNING NR 23// RMKS// 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 02W (SANBA), LOCATED APPROXIMATELY 180 NM SOUTH OF PUERTO PRINCESA, PHILIPPINES, HAS TRACKED WESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED MSI SHOWS THE CENTRAL CONVECTION BECOMING MORE DISORGANIZED AND SHEARED NORTHWESTWARD FROM A PARTIALLY EXPOSED, RAGGED, AND ELONGATED LLC. THE INITIAL POSITION IS BASED ON THE MSI LOOP WITH FAIR CONFIDENCE. THE INITIAL INTENSITY OF 25 KNOTS IS BASED ON THE HIGH END OF AGENCY DVORAK ESTIMATES RANGING FROM T1.0 TO T1.5. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS IN AN AREA OF MODERATE TO STRONG (20-25 KNOT) SOUTHEASTERLY VWS; HOWEVER, A ROBUST POLEWARD OUTFLOW IS PROVIDING VENTILATION TO THE SHEARED CONVECTION. SSTS IN THE AREA ARE MARGINALLY CONDUCIVE AT 27 CELSIUS. THE CYCLONE IS TRACKING ALONG THE SOUTHERN PERIPHERY OF A LOW REFLECTION OF THE STR TO THE NORTH. 3. FORECAST REASONING. A. THERE IS NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD SANBA IS EXPECTED TO STRUGGLE TO MAINTAIN TD INTENSITY AS IT NAVIGATES GENERALLY WESTWARD THROUGH THE NORTHERN TIP OF BORNEO INTO THE SOUTH CHINA SEA STEERED BY THE STR AND UNDER A PRECARIOUS BALANCE BETWEEN STRONG VWS AND STRONG OUTFLOW. AFTER TAU 36, TD 02W WILL TRACK OVER INCREASINGLY COOLER SSTS, TIPPING THE BALANCE AND LEADING TO EVENTUAL DISSIPATION BY TAU 72, POSSIBLY SOONER. DYNAMIC MODEL GUIDANCE IS IN GENERAL AGREEMENT ON A WESTWARD TRAJECTORY BUT WITH NOTABLE DIFFERENCES IN TRACK SPEED. IN VIEW OF THIS AND THE WEAK NATURE OF THE SYSTEM, THERE IS OVERALL A LOW CONFIDENCE IN THE FORECAST TRACK.// NNNN NNNN