Tropical Storm TRAMI Advisory Вс, 30.09.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 28W (TRAMI) WARNING NR 37//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 28W (TRAMI), LOCATED APPROXIMATELY 324 NM
SOUTH-SOUTHWEST OF IWAKUNI, JAPAN, HAS TRACKED NORTHEASTWARD AT 16
KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY SHOWS THE SYSTEM REMAINS EXPANSIVE (OVER 400 NM ACROSS) AND
HAS MAINTAINED A VERY LARGE AND RAGGED EYEWALL THAT HAS SLIGHTLY
DEEPENED WHILE SURROUNDING A 90-NM IRREGULAR EYE. THE INITIAL
POSITION IS BASED ON THE EYE FEATURE AND ON A TIGHTLY GROUPED CLUSTER
OF 291800Z AGENCY AND RADAR POSITION FIXES WITH HIGH CONFIDENCE. THE
INITIAL INTENSITY OF 95 KNOTS IS HEDGED SLIGHTLY HIGHER THAN
EQUIVALENT DVORAK ESTIMATES OF T5.0/90 KNOTS FROM PGTW, RJTD, AND
KNES TO REFLECT THE SLIGHTLY DEEPENED CENTRAL CONVECTION.
ENVIRONMENTAL ANALYSIS INDICATES THAT TY 28W IS NOW IN MODERATE TO
STRONG (20 TO 30 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.
SEA SURFACE TEMPERATURES (SSTS) REMAIN FAVORABLE AT 28 TO 29 CELSIUS.
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
POISED TO INTERACT WITH THE MAJOR ISLANDS OF JAPAN, TRACKING QUICKLY
ACROSS THE RUGGED TERRAIN. SHORTLY AFTER TAU 24, 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
ISLANDS WILL LEAD TO RAPID DECAY. CONCURRENTLY, THE SYSTEM WILL BEGIN
EXTRA-TROPICAL TRANSITION AROUND TAU 12 AND BY TAU 24, WILL BECOME A
STORM-FORCE COLD CORE LOW WITH AN EXPANDING WIND FIELD OVER
NORTHEASTERN HONSHU. BY TAU 36, THE SYSTEM WILL HAVE FULLY EMBEDDED
IN THE BAROCLINIC ZONE. DYNAMIC MODEL GUIDANCE IS IN VERY TIGHT
AGREEMENT; THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST
TRACK.//
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