WDPN31 PGTW 040900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 22W (GONI) WARNING NR 
030//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM 22W (GONI), LOCATED APPROXIMATELY 305 NM EAST-
SOUTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-SOUTHWESTWARD AT 04 
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE 
IMAGERY (MSI) DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER 
(LLCC) WITH FLARING DEEP CONVECTION BEING SHEARED TO THE NORTHWEST 
OF THE LLCC. THE INITIAL POSITION IS ASSESSED WITH HIGH CONFIDENCE 
BASED ON THE EXPOSED LLCC IN THE VISIBLE IMAGERY. THE INITIAL 
INTENSITY IS SET AT 35 KNOTS WITH FAIR CONFIDENCE BASED ON MULTI-
AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T2.5 (35 KNOTS) FROM 
BOTH PGTW AND RJTD, AND HEDGED BELOW THE ADVANCED DVORAK TECHNIQUE 
(ADT) ESTIMATE OF T3.1. TS 22W IS TRACKING THROUGH A MARGINAL 
ENVIRONMENT WITH MODERATE (15-20 KNOTS) EASTERLY VWS, MODERATE 
WESTWARD DIVERGENT OUTFLOW AND WARM (27 DEG CELSIUS) SSTS ALONG THE 
COAST OF VIETNAM. THE SYSTEM IS TRACKING GENERALLY TOWARDS THE WEST 
ALONG THE SOUTHERN PERIPHERY OF A DEEP-LAYER STR TO THE NORTH, 
ALTHOUGH THE LLCC HAS DEMONSTRATED SOME ERRATIC WOBBLING OVER THE 
PAST SIX HOURS AFTER EMERGING FROM UNDER THE SHEARED CONVECTION. 
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. THERE IS NO SIGNIFICANT CHANGE EXPECTED IN THE OVERALL 
STEERING ENVIRONMENT, WITH THE STEERING STR REMAINING ENTRENCHED TO 
THE NORTH, LEADING TO A WEST-SOUTHWESTWARD TRACK THROUGH THE ENTIRE 
FORECAST PERIOD. THE SYSTEM IS EXPECTED TO MAKE LANDFALL ALONG THE 
SOUTH-CENTRAL VIETNAM COAST NEAR TAU 40 AS A MINIMAL TROPICAL 
DEPRESSION. AS WITH THE STEERING PATTERN, THERE IS NO SIGNIFICANT 
CHANGE EXPECTED IN THE OVERALL INTENSIFICATION ENVIRONMENT, WITH THE 
CURRENT CONDITIONS FORECAST TO CONTINUE THROUGH TO LANDFALL, LEADING 
TO STEADY INTENSITY TO TAU 24, THEN SLOW WEAKENING AS IT NEARS 
THE COASTLINE AND VWS INCREASES AND SSTS COOL SLIGHTLY. DYNAMIC 
MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH LANDFALL, WITH 
INCREASING SPREAD THEREAFTER AS THE MODELS LOSE THE LOW LEVEL 
VORTEX, WITH THE EXCEPTION OF NAVGEM, WHICH CONTINUES TO TRACK THE 
SYSTEM UNREALISTICALLY POLEWARD. THE JTWC FORECAST LIES NEAR THE 
MULTI-MODEL CONSENSUS WITH GOOD CONFIDENCE.//
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