Tropical Storm CHAN-HOM Advisory Wed Jul 08

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (CHAN-HOM) WARNING NR 31//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 09W (CHAN-HOM), LOCATED APPROXIMATELY 517 NM
SOUTHEAST OF KADENA AB, OKINAWA, JAPAN, HAS TRACKED
WEST-NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED
MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM HAS MAINTAINED
OVERALL CONVECTIVE SIGNATURE EVEN AS ITS EYE FEATURE HAS BECOME
CLOUD-FILLED. THE INITIAL POSITION IS BASED ON THE MICROWAVE EYE
FEATURE IN THE 072212 SSSMIS IMAGE WITH HIGH CONFIDENCE. THE INITIAL
INTENSITY OF 80 KNOTS IS BASED ON THE CONGRUENT DVORAK ESTIMATES
FROM PGTW, KNES, AND RJTD. UPPER-LEVEL ANALYSIS DEPICTS A FAVORABLE
ENVIRONMENT WITH MODERATE (15-20 KNOT) VWS EASILY OFFSET BY RADIAL
OUTFLOW. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF
A DEEP-LAYERED EXTENSION OF THE STR TO THE NORTH.
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING MESSAGE.
   B. TY 09W IS FORECAST TO CONTINUE TRACKING NORTHWESTWARD UNDER
THE STEERING INFLUENCE OF THE STR THROUGH TAU 72. IT IS EXPECTED TO
INTENSIFY STEADILY PEAKING AT 120 KNOTS BY TAU 48 AS FAVORABLE
ENVIRONMENTAL CONDITIONS PERSIST. DYNAMIC GUIDANCE IS IN TIGHT
AGREEMENT THROUGH THIS PERIOD, LENDING HIGH CONFIDENCE TO THIS
PORTION OF THE TRACK FORECAST.
   C. AFTER TAU 72, TY CHAN-HOM WILL MAKE LANDFALL OVER SOUTHEASTERN
CHINA AND BEGIN TO TRACK POLEWARD AS THE STR EXTENSION RETREATS TO
THE EAST AND BREAKS DOWN DUE TO AN INBOUND MID-LATITUDE TROUGH. THE
SYSTEM WILL ERODE RAPIDLY DUE TO INCREASING VWS AND INTERACTION WITH
THE RUGGED TERRAIN. NUMERICAL GUIDANCE SPREAD OUT SIGNIFICANTLY
LENDING LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK,
WHICH IS LAID CLOSE TO THE MULTI-MODEL CONSENSUS.//
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