Tropical Storm DOKSURI Advisory 9月15日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 21W (DOKSURI)
WARNING NR 13//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 21W (DOKSURI), LOCATED APPROXIMATELY 100 NM NORTH-
NORTHEAST OF DA NANG, VIETNAM, HAS TRACKED WEST-NORTHWESTWARD AT 12
KNOTS OVER THE PAST SIX HOURS. THE CURRENT POSITION OF THE LOW LEVEL
CIRCULATION CENTER (LLCC) IS BASED ON A 141800Z INFRARED IMAGE AND
RECENT SATELLITE FIXES FROM PGTW AND RJTD. THE CURRENT INTENSITY OF
90 KNOTS IS BASED ON A DVORAK ESTIMATE OF T5.0 (90 KNOTS) FROM PGTW.
TY 21W HAS CONTINUED TO STEADILY INTENSIFY WHILE TRACKING WEST-
NORTHWESTWARD ALONG THE SOUTHERN PERIPHERY OF A SUBTROPICAL STEERING
RIDGE (STR). ANIMATED INFRARED SATELLITE IMAGERY SHOWS PERSISTENT
DEEP CONVECTION ALONG THE SOUTHERN AND EASTERN PORTIONS OF THE LLCC.
DOKSURI CONTINUES TO HAVE EXCELLENT EQUATORWARD UPPER LEVEL OUTFLOW.
POLEWARD UPPER LEVEL OUTFLOW IS NOT AS IMPRESSIVE.
3. FORECAST REASONING.
   A. THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST PHILOSOPHY FROM
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY DOKSURI WILL CONTINUE TRACKING GENERALLY WEST-NORTHWESTWARD
ALONG THE PERIPHERY OF THE CURRENT STEERING RIDGE THROUGHOUT THE
FORECAST PERIOD. LOW VERTICAL WIND SHEAR (10-15 KNOTS), FAVORABLE
EQUATORWARD OUTFLOW IN THE UPPER LEVELS AND HIGH SEA SURFACE
TEMPERATURES (30-31 CELSIUS) WILL SUPPORT MAINTAINING CURRENT
INTENSITY THROUGH TAU 12. TY 21W WILL MAKE LANDFALL SHORTLY BEFORE
TAU 12 AND WILL DISSIPATE STEADILY AND SLOW IN FORWARD SPEED AS IT
MOVES INLAND. NUMERICAL MODELS ARE IN GOOD AGREEMENT, AND THE
CURRENT JTWC OFFICIAL FORECAST LIES NEAR THE MULTI-MODEL CONSENSUS
WITH HIGH CONFIDENCE.//
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