WDPN31 PGTW 020900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL DEPRESSION 22W (GONI) 
WARNING NR 022//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL DEPRESSION (TD) 22W (GONI), LOCATED APPROXIMATELY
562 NM EAST OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD
AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY (MSI) SHOWS A WEAKENED, ALBEIT FLARING, 
CENTRAL CONVECTION THAT HAS SHEARED APPROXIMATELY 85NM AWAY 
FROM A FULLY EXPOSED AND RAGGED LOW LEVEL CIRCULATION (LLC). 
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON 
THE LLC THAT LINED UP WELL WITH A DEFINED MICROWAVE LLC FEATURE
IN THE 020509Z AMSR2 IMAGE. THE INITIAL INTENSITY OF 30KTS IS 
BASED ON THE DVORAK ESTIMATE OF T2.0/30KTS FROM PGTW AND 
REFLECTS THE SIGNIFICANT DETERIORATION. UPPER LEVEL ANALYSIS
INDICATES A MARGINAL ENVIRONMENT WITH HIGH (30 KTS+) VERTICAL 
WIND SHEAR (VWS) OFFSET BY STRONG WESTWARD OUTFLOW. THE CYCLONE
IS TRACKING IN THE SOUTH CHINA SEA OVER WARM (29C) 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. TD 22W WILL TRACK MORE WEST-SOUTHWESTWARD AS THE STR BUILDS,
AND BY TAU 72, WILL BE APPROXIMATELY 75NM OFF THE COAST OF SOUTHERN 
VIETNAM. THE ENVIRONMENT WILL IMPROVE SLIGHTLY AS ROBUST UPPER 
LEVEL OUTFLOW OVERCOMES THE STRONG VWS AND WILL LEAD TO A MODEST 
INTENSIFICATION TO 40KTS BY TAU 36, SUSTAINED UP TO TAU 72.
NUMERICAL MODELS ARE IN GOOD AGREEMENT WITH A GRADUAL AND EVEN
SPREAD TO 270NM BY TAU 72, AND LENDS FAIR CONFIDENCE TO THIS
PORTION OF THE JTWC FORECAST TRACK. 
   C. BEYOND TAU 72, TD GONI WILL MAKE LANDFALL NEAR QUI NHON
BY TAU 84. INTERACTION WITH THE UNDERLYING TERRAIN WILL LEAD TO
DISSIPATION BY TAU 96 NEAR THE BORDER WITH CAMBODIA. NUMERICAL 
MODELS SPREAD OUT SIGNIFICANTLY, LENDING LOW CONFIDENCE TO THIS
FINAL PORTION OF THE JTWC FORECAST TRACK. THERE IS A DISTINCT
POSSIBILITY THAT TD 22W WILL DISSIPATE OVER WATER PRIOR TO 
LANDFALL DUE TO HIGH VWS AND COOLING SST.//
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