WDPN31 PGTW 032100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (GONI) 
WARNING NR 026//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 22W (GONI), LOCATED APPROXIMATELY 401 NM EAST 
OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP FLARING CONVECTION THAT IS BEING SHEARED OFF RAPIDLY TO THE NORTHWEST. THE INITIAL POSITION IN PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE VISIBLE IMAGERY. THE INITIAL INTENSITY OF 35KTS IS BASED ON AN ASSESSMENT MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.5 FROM PGTW AND RJTD, AND A T3.0 FROM KNES WITH SUPPORT FROM A 030229Z ASCAT-B PASS WHICH INDICATED A VERY SMALL PATCH OF 35-40 KNOT WINDS UNDER THE CONVECTION TO THE NORTHWEST, WHILE THE REMAINDER OF THE CIRCULATION HAS MEASURED WINDS OF 30 KNOTS OR LESS. 
ENVIRONMENTAL ANALYSIS INDICATES THAT THEY SYSTEM LIES IN A MARGINAL TO UNFAVORABLE REGION WITH MODERATE TO HIGH (20-25 KNOTS) EASTERLY VWS, MODERATE WESTWARD OUTFLOW AND WARM (27 TO 28 DEG CELSIUS) SSTS. THE SYSTEM IS STILL TRACKING GENERALLY WEST, BUT HAS SLOWED SIGNIFICANTLY OVER THE PAST SIX HOURS AS THE STEERING PATTERN HAS WEAKENED IN RESPONSE TO AN EXPANSION OF THE COL REGION BETWEEN THE SUBTROPICAL RIDGES (STR) LOCATED OVER SOUTHERN CHINA AND A SECOND CENTER NORTH OF GUAM.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. OVER THE NEXT 12 TO 24 HOURS, THE STEERING PATTERN WILL STRENGTHEN AS THE STR OVER SOUTHERN CHINA BUILDS AND EXTENDS EASTWARD, ALLOWING TS 22W TO ACCELERATE SLIGHTLY AND TRACK WEST-SOUTHWESTWARD THROUGH TAU 72, MAKING LANDFALL IN SOUTH-CENTRAL VIETNAM AROUND TAU 68. THE INTENSIFICATION ENVIRONMENT IS FORECAST TO BECOME INCREASINGLY UNFAVORABLE WITH MODERATE TO HIGH VWS, AND DECREASING SSTS OFFSETTING MODERATE WESTWARD OUTFLOW. AND LEAD TO A SLOW WEAKENING TREND AFTER TAU 12. NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A GRADUALLY INCREASING SPREAD TO 200 NM BY TAU 72. THE NVGM TRACKER HAS BEEN DISCOUNTED, AS IT TAKES THE SYSTEM FAR TO THE NORTH NEAR HAINAN BY TAU 72, WHICH IS CONSIDERED HIGHLY UNLIKELY. THE JTWC FORECAST LIKES ALONG THE NORTHERN SIDE OF THE GUIDANCE ENVELOPE IN LIGHT OF THE NEAR-TERM SLOW, WESTWARD MOTION, WITH FAIR CONFIDENCE. //
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