WDPN31 PGTW 022100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (GONI) 
WARNING NR 024//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 22W (GONI), LOCATED APPROXIMATELY 437 NM EAST 
OF DA NANG, VIETNAM, HAS TRACKED WESTWARD AT 11 KNOTS OVER THE PAST 
SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS 
A WEAK SYSTEM WITH FLARING CENTRAL CONVECTION THAT IS SHEARED 
WESTWARD AFTER INITIALLY BUILDING OVER THE LOW LEVEL CIRCULATION 
(LLC) TO REVEAL A PARTIALLY EXPOSED AND RAGGED LLC. THE INITIAL 
POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON A 021625Z GMI 89GHZ 
MICROWAVE IMAGE THAT DEPICTS LOW-LEVEL BANDING WRAPPING INTO THE LLC 
AND CONVECTION DISPLACED JUST TO THE WEST. THE INITIAL INTENSITY OF 
35KTS IS BASED ON A DVORAK ESTIMATE OF T2.5/35KTS FROM PGTW AND A 
021357Z ASCAT-B IMAGE THAT SHOWS A POCKET OF 35KT WINDS IN THE 
NORTHWEST QUADRANT. UPPER LEVEL ANALYSIS INDICATES A MARGINAL 
ENVIRONMENT WITH HIGH (25-30 KTS) VERTICAL WIND SHEAR (VWS) OFFSET 
BY STRONG WESTWARD OUTFLOW. THE CYCLONE IS TRACKING THROUGH THE 
SOUTH CHINA SEA OVER WARM (28C) SEA SURFACE TEMPERATURES, STEERED BY 
A DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE NORTHWEST.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS 
PROGNOSTIC REASONING MESSAGE.
   B. TS 22W WILL CONTINUE TO TRACK WESTWARD THROUGH TAU 12, THEN 
WEST-SOUTHWESTWARD AS THE STR BUILDS, MAKING LANDFALL IN VIETNAM 
JUST PRIOR TO TAU 72. THE ENVIRONMENT WILL IMPROVE SLIGHTLY AS 
ROBUST UPPER LEVEL OUTFLOW OVERCOMES THE STRONG VWS AND WILL LEAD TO 
A MODEST PEAK INTENSIFICATION TO 40KTS AT TAUS 24-36. AFTERWARD, 
VWS, COOLING SST, AND INTERACTION WITH THE LAND AS IT NEARS VIETNAM 
WILL OFFSET THE STRONG OUTFLOW AND WEAKEN THE SYSTEM DOWN TO 25KTS 
BY TAU 72. NUMERICAL MODELS ARE IN FAIR AGREEMENT WITH A GRADUAL AND 
EVEN SPREAD TO 225NM BY TAU 72, LENDING FAIR CONFIDENCE TO THIS 
PORTION OF THE JTWC FORECAST TRACK. 
   C. BEYOND TAU 72, TS GONI WILL CONTINUE TO TRACK INLAND WHERE 
INTERACTION WITH THE RUGGED TERRAIN, IN ADDITION TO THE UNFAVORABLE 
ENVIRONMENT WILL FURTHER ERODE THE SYSTEM LEADING TO DISSIPATION BY 
TAU 96. NUMERICAL MODELS CONTINUE TO SPREAD THROUGH TAU 96, LENDING 
LOW CONFIDENCE TO THIS FINAL PORTION OF THE JTWC FORECAST TRACK. 
THERE IS A DISTINCT POSSIBILITY THAT TS 22W WILL DISSIPATE OVER 
WATER PRIOR TO LANDFALL DUE TO HIGH VWS AND COOLING SST OVERCOMING 
THE ROBUST OUTFLOW.//
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