WDPN31 PGTW 031500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (GONI) WARNING NR 
027//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 22W (GONI), LOCATED APPROXIMATELY 373 NM EAST 
OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 05 KNOTS OVER THE PAST 
SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) SHOWS 
THAT THE PREVIOUSLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) HAS 
RECENTLY TUCKED UNDER THE EASTERN EDGE OF DEEP, FLARING CONVECTION, 
THOUGH THE SYSTEM LACKS ANY WELL DEFINED CONVECTIVE BANDING. THE 
INITIAL POSITION IN PLACED WITH HIGH CONFIDENCE BASED ON THE AN 
ASSESSMENT OF THE OUTER LOW LEVEL CLOUD BANDS WRAPPING INTO THE 
OBSCURED LLCC, SUPPORTED BY A 031222Z ASCAT-A BULLSEYE PASS. THE 
INITIAL INTENSITY IS SET AT OF 35KTS WITH FAIR CONFIDENCE BASED ON 
AN A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.5 (35 KNOTS), AND 
HEDGED BELOW AN ADVANCED DVORAK TECHNIQUE (ADT) ESTIMATE OF T3.0 (45 
KNOTS) DUE TO THE RAW ADT VALUE BEING ONLY T2.0 (30 KONTS), 
CONFIRMED BY THE 031222Z ASCAT-A PASS WHICH SHOWS A SMALL AREA OF 
35KT WINDS ON THE NORTHWEST SIDE OF THE CENTER UNDER THE FLARING 
CONVECTION. TS 22W REMAINS ENSCONCED IN A MARGINAL ENVIRONMENT, WITH 
MODERATE TO HIGH (20-25 KNOTS) EASTERLY VWS, MODERATE WESTWARD 
OUTFLOW AND  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 TRACKING TO THE WEST ALONG THE SOUTHERN PERIPHERY OF A 
DEEP-LAYER STR LOCATED TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. OVER THE NEXT 12, THE STEERING PATTERN WILL SHIFT SLIGHTLY, 
WITH THE STR REORIENTING TO A MORE SOUTHWEST TO NORTHEAST AXIS, 
ALLOWING TS 22W TO BEGIN TRACKING MORE TOWARDS THE SOUTHWEST. THE 
SYSTEM IS FORECAST TO MAKE LANDFALL ALONG THE SOUTH-CENTRAL 
VIETNAMESE COAST AROUND TAU 60. THERE IS NO SIGNIFICANT CHANGE 
FORECAST IN THE OVERALL ENVIRONMENTAL CONDITIONS, WITH VWS FORECAST 
TO REMAIN AT MODERATE LEVELS, AND OUTFLOW CONSTRICTED TO A SINGLE 
WESTWARD CHANNEL, INHIBITING ANY SIGNIFICANT INTENSIFICATION. AFTER 
TAU 24, SSTS WILL STEADILY COOL AND OHC VALUES DECREASE, WITH THE 
NET RESULT BEING A STEADY WEAKENING TREND AFTER TAU 24 THROUGH TO 
LANDFALL. DYNAMIC MODEL GUIDANCE IS A FAIR AGREEMENT, WITH TRACKERS 
DIVERGING AFTER TAU 24 AS THE VORTEX WEAKENS AND MODELS HAVE A 
DIFFICULT TIME TRACKING THE WEAKENED LLCC.  SPREAD BETWEEN OUTLIERS 
INCREASES TO 250 NM BY TAU 72. THE NVGM TRACKER REMAINS THE NOTABLE 
POLEWARD OUTLIER, DIVERGING OVER 200NM NORTH OF THE NORTHERNMOST 
TRACKER WITHIN THE MAIN GUIDANCE ENVELOPE, AND HAS THUS BEEN 
DISCOUNTED. THE JTWC FORECAST LIES JUST SOUTH OF THE MULTI-MODEL 
CONSENSUS WITH HIGH CONFIDENCE.//
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