Tropical Storm GONI Advisory Mon Aug 17

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 16W (GONI) WARNING NR 15//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 16W (GONI), LOCATED APPROXIMATELY 392 NM NORTHWEST OF
ANDERSEN AFB, HAS TRACKED WEST-NORTHWESTWARD AT 12 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED IR IMAGERY DEPICTS A CONSOLIDATED
LLCC WITH AN OCCLUDED EYE. THE CONFIDENCE REMAINS HIGH FOR THE
POSITION OF THIS SYSTEM DESPITE THE LACK OF SOLID MICROWAVE DATA. TY
GONI IS UNDERGOING RAPID INTENSIFICATION, INCREASING NEARLY 60 KNOTS
OVER THE PAST 24 HOURS WITH AN ASSESSED CURRENT INTENSITY OF 115 KNOTS
BASED ON AN AVERAGE OF CURRENT INTENSITY ESTIMATES FROM ALL AGENCIES.
UPPER LEVEL ANALYSIS SHOWS LOW ( ABOUT 15 KNOTS) VWS AND VIGOROUS DUAL
CHANNEL OUTFLOW. TY 16W CONTINUES TO TRACK ALONG THE SOUTHERN
PERIPHERY OF THE DEEP STR.
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. DUE TO THE FAVORABLE
ENVIRONMENTAL CONDITIONS, INCLUDING LOW VWS, WARM SST AND EXCELLENT
OUTFLOW, TY 16W IS FORECAST TO CONTINUE TO INTENSIFY RAPIDLY THROUGH
TAU 24 WITH A PEAK OF 125 KNOTS. HOWEVER, DUE TO INCREASED VWS,
EXPECT A SLIGHT DIP IN INTENSITY AROUND TAU 36 DUE TO AN INCREASE IN
VWS. BY TAU 48, THE SYSTEM WILL RE-INTENSIFY TO A SECOND PEAK OF 130
KNOTS AT TAU 72 DUE TO IMPROVED POLEWARD OUTFLOW CAUSED BY THE
PASSING OF THE SHORTWAVE TROUGH.
   C. IN THE EXTENDED PERIOD, MODEL GUIDANCE WIDENS WITH REGARD TO
BOTH SPEED AND TIMING. THE STEERING ENVIRONMENT BECOMES MORE
COMPLICATED WITH THE PASSING MID-LATITUDE SHORTWAVE TROUGH AND A SMALL
EXTENSION OF THE STR ANCHORED OVER SHIKOKU. THE MARGINAL BREAK IN THE
RIDGE DUE TO THE PASSING SHORTWAVE TROUGH WILL PROVIDE SOME LIMITED
OPPORTUNITY FOR TY 16W TO TRACK TO THE NORTH. AS SUCH, TY GONI IS
EXPECTED TO SLOW ITS TRACK AND SLOWLY TURN POLEWARD DUE TO THE WEAK
STEERING ENVIRONMENT, TO INCLUDE SOME INFLUENCE OF TY 17W TRACKING
ALONG THE EASTERN PERIPHERY OF THE SHIKOKU STR, REINFORCING THE RIDGES
POSITION. INTENSITY IS EXPECTED TO DECREASE DURING THE EXTENDED
FORECAST DUE TO LAND INTERACTION. BECAUSE OF THE COMPLEX STEERING
ENVIRONMENT IN THE EXTENDED FORECAST, THERE IS HIGH UNCERTAINTY IN
THE JTWC FORECAST TRACK.//
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