Tropical Storm TRAMI Advisory Sun Sep 30

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI) WARNING NR 38//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 28W (TRAMI), LOCATED APPROXIMATELY 229 NM
SOUTH-SOUTHWEST OF IWAKUNI, JAPAN, HAS TRACKED NORTHEASTWARD AT 19
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY SHOWS THE SYSTEM REMAINS EXPANSIVE AND HAS MAINTAINED A VERY
LARGE AND RAGGED EYEWALL SURROUNDING AN 80 BY 100 NM RAGGED OBLONG
EYE. FEEDER BANDS REMAIN DEEP AND EXTEND OVER 250 NM FROM THE CENTER.
THE INITIAL POSITION IS BASED ON THE EYE FEATURE AND ON A TIGHT
CLUSTER OF 300000Z AGENCY AND RADAR POSITION FIXES WITH HIGH
CONFIDENCE. THE INITIAL INTENSITY OF 90 KNOTS IS BASED ON EQUIVALENT
DVORAK ESTIMATES OF T5.0/90 KNOTS FROM PGTW, RJTD, AND KNES.
ENVIRONMENTAL ANALYSIS INDICATES THAT TY 28W IS IN STRONG (GREATER
THAN 25 KNOT) VERTICAL WIND SHEAR (VWS); HOWEVER, THIS IS BEING
OFFSET BY EXCELLENT RADIAL OUTFLOW WITH A STRONG POLEWARD CHANNEL
INTO THE MID-LATITUDE TROUGH DIGGING IN FROM THE NORTHWEST AND THE
STORM MOTION BEING IN-PHASE WITH THE UPPER LEVEL WIND VECTOR. SEA
SURFACE TEMPERATURES (SSTS) HAVE COOLED TO 26 CELSIUS BUT REMAIN
FAVORABLE. THE CYCLONE IS TRACKING ALONG THE NORTHWESTERN PERIPHERY
OF THE DEEP-LAYERED SUBTROPICAL RIDGE TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY TRAMI WILL CONTINUE TO ACCELERATE NORTHEASTWARD AND IS NOW
INTERACTING WITH KYUSHU, JAPAN. IT WILL TRACK QUICKLY ACROSS THE
RUGGED JAPANESE TERRAIN AND SHORTLY AFTER TAU 18, THE CYCLONE WILL
EXIT BACK INTO THE PACIFIC OCEAN, ALBEIT WITH MUCH COOLER SSTS, JUST
EAST OF MISAWA. INCREASING VWS PLUS INTERACTION WITH THE JAPANESE
ALPS WILL LEAD TO RAPID DECAY. CONCURRENTLY, THE SYSTEM HAS BEGUN
EXTRA-TROPICAL TRANSITION AND BY TAU 24, WILL BECOME A STRONG
GALE-FORCE COLD CORE LOW WITH AN EXPANDING WIND FIELD. DYNAMIC MODEL
GUIDANCE IS IN VERY TIGHT AGREEMENT; THEREFORE, THERE IS HIGH
CONFIDENCE IN THE JTWC FORECAST TRACK.//
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