Tropical Storm GONI Advisory Fri Aug 21

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (GONI) WARNING NR 31//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 16W (GONI), LOCATED APPROXIMATELY 345 NM SOUTH OF
TAIPEI, TAIWAN, HAS TRACKED NORTHWARD AT 01 KNOT OVER THE PAST SIX
HOURS. ANIMATED ENHANCED IR SATELLITE IMAGERY DEPICTS A CLOUD-FILLED
12 NM EYE WITH GOOD CONFIDENCE IN THE CURRENT POSITION. A 211028Z
SSMIS IMAGE SHOWS A PARTIAL EYEWALL WITH TIGHTLY-CURVED BANDING
LOCATED PRIMARILY OVER THE SOUTHERN SEMI-CIRCLE. UPPER-LEVEL
ANALYSIS INDICATES NEAR-RADIAL OUTFLOW WITH WEAK CONVERGENT FLOW AND
MODERATE NORTHERLY VERTICAL WIND SHEAR OVER THE NORTHERN PERIPHERY
OF THE SYSTEM. THE CURRENT INTENSITY IS ASSESSED AT 95 KNOTS BASED
ON DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM ALL AGENCIES. TY
16W IS NEARLY STATIONARY, POSSIBLY TROCHOIDAL MOVEMENT, ALONG THE
SOUTHERN PERIPHERY OF A WEAK NARROW STR TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 16W IS FORECAST TO REMAIN NEARLY STATIONARY OVER THE NEXT
12 HOURS, WITH THE POTENTIAL TO SPEED UP SLIGHTLY, AS THE STEERING
ENVIRONMENT REMAINS WEAK. THE RECENT 500 MB ANALYSIS, AS WELL AS
WATER-VAPOR IMAGERY, SHOWS THE STR TO THE NORTH CONTINUING TO
WEAKENING. AFTER TAU 12, THE STR IS FORECAST TO RE-BUILD EAST OF THE
SYSTEM PROVIDING A POLEWARD ORIENTED TRACK, WHICH SHOULD ALLOW THE
SYSTEM TO SLOWLY TRACK NORTHWARD. TY 16W SHOULD WEAKEN GRADUALLY
THROUGH THE FORECAST PERIOD DUE TO LAND INTERACTION AND INCREASED
UPPER-LEVEL CONVERGENCE ASSOCIATED WITH THE UPPER-LEVEL SUBTROPICAL
WESTERLIES ENCROACHING ON THE WESTERN PERIPHERY OF THE SYSTEM.
   C. IN THE EXTENDED PERIOD, TY 16W WILL TURN NORTHEASTWARD AS IT
TRACKS ALONG THE NORTHWESTERN PERIPHERY OF THE STR. TY GONI WILL
WEAKEN SIGNIFICANTLY AS IT TRACK THOUGH SOUTHERN JAPAN AND INTO THE
COOL WATERS OF THE SEA OF JAPAN. ADDITIONALLY, THE SYSTEM WILL BEGIN
SLIGHT INTERACTION WITH THE BAROCLINC ZONE BY TAU 96 AND COMPLETING
ETT BY THE END OF THE FORECAST PERIOD, BEING COMPLETELY ENVELOPED BY
THE WESTERLIES. DYNAMIC GUIDANCE IS IN GOOD AGREEMENT, HOWEVER, DUE
TO THE COMPLEX STEERING ENVIRONMENT IN THE EARLY PORTION OF THE
FORECAST, THERE REMAINS  LOW CONFIDENCE IN THE JTWC FORECAST TRACK.//
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