Tropical Storm FRANCISCO Advisory 8月6日

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 09W (FRANCISCO) WARNING
NR 17//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 09W (FRANCISCO), LOCATED APPROXIMATELY 140 NM SOUTHEAST OF
SASEBO, JAPAN, HAS TRACKED WEST-NORTHWESTWARD AT 11 KNOTS OVER THE
PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS A
WELL DEFINED SYSTEM WITH A SMALL EYE FEATURE. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE AND IS BASED ON A 051750Z HIMAWARI
INFRARED SATELLITE IMAGE, WHICH SHOWS THE EYE AND THE SURROUNDING
DEEP CONVECTION. THE INITIAL INTENSITY ESTIMATE OF 75 KNOTS IS BASED
ON DVORAK CURRENT INTENSITY (CI) ESTIMATES OF T4.5 (77 KNOTS) FROM
PGTW AND RJTD. ENVIRONMENTAL ANALYSIS SHOWS TY 09W IS EXPERIENCING
FAVORABLE VERTICAL WIND SHEAR (10 TO 15 KNOTS). TY 09W ALSO HAS GOOD
POLEWARD AND EQUATORWARD OUTFLOW CHANNELS ALONG WITH FAVORABLE SEA
SURFACE TEMPERATURES (29 TO 30 DEGREES CELSIUS). TY 09W IS TRACKING
WEST-NORTHWESTWARD WHILE UNDER THE INFLUENCE OF A SUBTROPICAL RIDGE
(STR) LOCATED TO THE SOUTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE OVERALL FORECAST PHILOSOPHY SINCE
THE PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY 09W WILL TRACK NORTHWESTWARD THROUGH TAU 12 WHILE IT REMAINS
UNDER THE INFLUENCE OF THE AFOREMENTIONED STR. BY TAU 03, TY 09W WILL
MAKE LAND FALL IN SOUTHERN KYUSHU. LAND INTERACTION WILL CAUSE TY 09W
TO WEAKEN IN INTENSITY, REACHING 55 KNOTS BY TAU 12. ALSO BY TAU 12,
09W WILL BEGIN TO TURN MORE NORTHWARD ALONG THE WESTERN EDGE OF THE
STR. AN APPROACHING WEST TO EAST MOVING SHORTWAVE TROUGH WILL HELP TO
ACCELERATE TY 09W NORTHWARD AND EVENTUALLY NORTHEASTWARD BY TAU 36.
FRANCISCO WILL WEAKEN SLOWLY AS IS PASSES OVER OPEN WATER NORTH OF
KYUSHU AND SOUTH OF THE KOREAN PENINSULA. BY TAU 36, 09W WILL
INTERACT WITH THE BAROCLINIC ZONE AND BEGIN EXTRA-TROPICAL TRANSITION
(ETT). TY 09W WILL COMPLETE ETT BY TAU 72. NUMERICAL MODEL GUIDANCE
IS IN TIGHT AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE
JTWC FORECAST TRACK.//
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