Tropical Storm GONI Advisory Tue Aug 18

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (GONI) WARNING NR 19//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 16W (GONI), LOCATED APPROXIMATELY 546 NM
SOUTH-SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED WESTWARD AT
16 KNOTS OVER THE PAST SIX HOURS. RECENT ANIMATED ENHANCED INFRARED
SATELLITE IMAGERY SHOWS A SLIGHT WARMING OF CONVECTIVE TOPS,
OTHERWISE, THE SYSTEM HAS MAINTAINED OVERALL CONVECTIVE SIGNATURE WITH
TIGHTLY-CURVED BANDING WRAPPING INTO A 15-NM DIAMETER EYE. THE INITIAL
POSITION IS BASED ON THE EYE FEATURE WITH HIGH CONFIDENCE. THE
INITIAL INTENSITY OF 100 KNOTS IS HELD SLIGHTLY LOWER THAN THE
CONGRUENT DVORAK ESTIMATES FROM PGTW AND RJTD TO REFLECT THE SLIGHT
WEAKENING. UPPER-LEVEL ANALYSIS INDICATES LOW TO MODERATE (10 TO 20
KNOT) VWS AND SUBSIDENCE ALONG THE NORTHERN PERIPHERY THAT ARE OFFSET
BY STRONG EQUATORWARD OUTFLOW. THE CYCLONE IS TRACKING ALONG THE
SOUTHERN PERIPHERY OF THE DEEP STR TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 16W WILL CONTINUE TO TRACK WEST-NORTHWESTWARD THROUGH TAU 72
UNDER THE STEERING INFLUENCE OF THE STR. MARGINALLY FAVORABLE
CONDITIONS ALONG WITH CONTINUED SUBSIDENCE TO THE NORTH WILL LIMIT
THE INTENSIFICATION IN THE NEAR TERM. BY TAU 48, ENVIRONMENTAL AND
UPPER-LEVEL CONDITIONS ARE EXPECTED TO IMPROVE, ALLOWING TY 16W TO
RE-INTENSIFY, PEAKING AT 115 KNOTS BY TAU 48.
   C. IN THE EXTENDED TAUS, AN UPPER-LEVEL TROUGH PASSING TO THE
NORTH WILL WEAKEN THE STR, CAUSING TY 16W TO SHIFT POLEWARD. DEGRADED
UPPER-LEVEL CONDITIONS WILL BEGIN TO WEAKEN THE SYSTEM. AVAILABLE
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT THROUGH TAU 72, BUT
CONTINUES TO SHOW A SPREAD IN THE LATER TAUS. DUE TO THE UNCERTAINTY
IN THE TIMING OF THE POLEWARD TURN, THE JTWC TRACK FORECAST
CONFIDENCE LEVEL REMAINS LOW.//
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