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