WDPN32 PGTW 310300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 23W (ATSANI) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. TROPICAL DEPRESSION 23W (ATSANI), LOCATED APPROXIMATELY 247 NM NORTH-NORTHEAST OF YAP, HAS TRACKED NORTHWESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A VERY DISORGANIZED AND WEAK SYSTEM, WITH DISORGANIZED, FLARING CONVECTION NEAR THE ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS BASED ON THE LOW LEVEL CIRCULATION FEATURES PRESENT IN THE MSI LOOP AND IS PLACED WITH OVERALL POOR CONFIDENCE DUE TO THE LACK OF CONVECTIVE ORGANIZATION. THE INITIAL INTENSITY OF 25 KTS IS PLACED WITH HIGH CONFIDENCE AND IS HEDGED SLIGHTLY LOWER THAN MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.0 (30 KTS, PGTW AND RJTD) DUE TO THE 20-25 KTS WINDS PRESENT IN THE SCATTEROMETRY DATA FROM A 302256Z ASCAT-A PASS. THE OVERALL ENVIRONMENT IS UNFAVORABLE DUE TO HIGH (20-25 KTS) VERTICAL WIND SHEAR AND WEAK OUTFLOW ALOFT OFFSET SLIGHTLY BY FAVORABLE (30-31 CELSIUS) SEA SURFACE TEMPERATURES (SST). TD ATSANI IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP-LAYER SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST. 3. FORECAST REASONING. A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS PROGNOSTIC REASONING MESSAGE. B. TD 23W IS FORECAST TO CONTINUE TRACKING GENERALLY NORTHWESTWARD THROUGH TAU 72 ALONG THE SOUTHWESTERN EDGE OF THE STR POSITIONED TO THE NORTHEAST. THE ENVIRONMENT IS FORECAST TO IMPROVE SLIGHTLY TO MARGINAL BY TAU 24 AS WARM (29-30 CELSIUS) SST ARE OFFSET BY CONTINUED MODERATE TO HIGH (15-25 KTS) VWS AND PERIODS OF CONVERGENT FLOW ALOFT. THIS MARGINAL ENVIRONMENT WILL ALLOW FOR ONLY GRADUAL INTENSIFICATION DURING THIS TIME AND RESULT IN AN INTENSITY OF 45 KTS BY TAU 36. THEREAFTER, THE SYSTEM WILL BEGIN A MORE WEST- NORTHWESTWARD TRACK THROUGH TAU 72 AS A REORIENTATION OF THE STEERING RIDGE TAKES PLACE. BETWEEN TAU 36 AND TAU 72, GRADUAL INTENSIFICATION WILL TAKE PLACE DUE TO CONTINUED ENVIRONMENTAL CONDITIONS, WITH LOW (5-10 KTS) OVERALL VWS AND CONTINUED WARM SST. NUMERICAL MODEL TRACK GUIDANCE DIVERGES SIGNIFICANTLY DURING THIS TIME WITH A MAXIMUM ACROSS TRACK SPREAD IN SOLUTIONS OF 300 NM BY TAU 72. THIS SPREAD IN SOLUTIONS LENDS OVERALL FAIR CONFIDENCE IN THIS INITIAL PORTION OF THE JTWC FORECAST, WHICH IS PLACED SLIGHTLY SOUTH OF THE MULTI-MODEL CONSENSUS. C. IN THE EXTENDED FORECAST, TD ATSANI WILL TRACK WESTWARD AND THEN GENERALLY SOUTHWESTWARD THROUGH TAU 120. ENVIRONMENTAL CONDITIONS ARE FORECAST TO IMPROVE DURING THIS TIME WITH CONTINUED LOW VWS AND IMPROVED UPPER LEVEL DIVERGENCE. THESE CONDITIONS, COUPLED WITH CONTINUED WARM SST, WILL ALLOW FOR FURTHER INTENSIFICATION TO 105 KTS BY TAU 120. NUMERICAL MODEL TRACK GUIDANCE IS IN OVERALL POOR AGREEMENT DURING THIS TIME WITH AN ACROSS TRACK SPREAD OF 410 NM BY TAU 120. THIS SPREAD IN TRACK GUIDANCE LENDS OVERALL POOR CONFIDENCE IN THE REMAINDER OF THE JTWC FORECAST TRACK WHICH IS PLACED SLIGHTLY SOUTH OF THE MULTI-MODEL CONSENSUS.// NNNN