202100Z POSITION NEAR 31.5N 127.3E. TROPICAL DEPRESSION 04W (LEEPI), LOCATED APPROXIMATELY 215 NM WEST- SOUTHWESTWARD OF SASEBO, JAPAN, HAS TRACKED NORTH-NORTHEASTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE LOW LEVEL CIRCULATION CENTER HAS STARTED TO ELONGATE AS THE INTERACTION WITH THE BAROCLINIC ZONE (BAIU BOUNDARY) POSITIONED NEAR CHEJU ISLAND AMPLIFIES. THE SYSTEM HAS STARTED THE PROCESS OF EXTRA-TROPICAL TRANSITION (ETT) AND IS EXPECTED TO COMPLETE THE ETT PROCESS IN THE NEXT 12 HOURS. THE CURRENT FORECAST EXTENDS THE ET POSITIONS THROUGH TAU 36, AS MODEL GUIDANCE INDICATES THE SYSTEM WILL INTENSIFY AS A COLD-CORE LOW ALONG THE SOUTHERN COAST OF JAPAN INTO THE WESTERN PACIFIC. MODERATE TO HIGH (25 TO 30 KNOTS) OF VERTICAL WIND SHEAR, IN ASSOCIATION WITH INCREASED BAROCLINIC INTERACTION, AND DECREASING SEA SURFACE TEMPERATURES HAVE LED TO A FASTER THAN EXPECTED TRANSITION OF THE SYSTEM. DYNAMIC MODEL GUIDANCE REMAINS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 201800Z IS 12 FEET. REFER TO TROPICAL DEPRESSION 05W (FIVE) WARNINGS (WTPN32 PGTW) FOR SIX-HOURLY UPDATES.
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