Tropical Storm MITAG Advisory Sa, 01.10.

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (MITAG) WARNING NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 19W (MITAG), LOCATED APPROXIMATELY 547 NM SOUTHWEST
OF SASEBO, JAPAN, HAS TRACKED NORTHWARD AT 17 KNOTS OVER THE PAST
SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY INDICATES
SLIGHT WEAKENING OF CORE CONVECTION WITH THE BULK OF THE CONVECTION
DISPLACED OVER THE NORTHERN SEMICIRCLE. HOWEVER, A 301803Z AMSR2
36GHZ IMAGE DEPICTS A WELL-DEFINED MICROWAVE EYE FEATURE WITH
TIGHTLY-CURVED SHALLOW BANDING. DESPITE THE SLIGHT WEAKENING TREND,
THE INITIAL INTENSITY IS ASSESSED AT 90 KNOTS BASED ON DVORAK
INTENSITY ESTIMATES OF T5.0 (90 KNOTS) FROM PGTW AND KNES AND A
301311Z SATCON ESTIMATE OF 99 KNOTS. ADDITIONALLY, A 300938Z SMAP
PASS SHOWED PEAK WINDS OF 89 KNOTS (1-MINUTE AVERAGE). OVERALL,
THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION BASED ON THE AMSR2
IMAGE. UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY-FAVORABLE
ENVIRONMENT WITH MODERATE TO STRONG (20-30 KNOTS) SOUTHERLY VERTICAL
WIND SHEAR (VWS) OFFSET BY ROBUST POLEWARD OUTFLOW. SST VALUES HAVE
DECREASED SLIGHTLY TO 26C. TY 19W IS TRACKING ALONG THE WESTERN
PERIPHERY OF A NORTH-SOUTH ORIENTED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE EAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE. THE WIND RADII HAVE BEEN
ADJUSTED BASED ON A DETAILED ANALYSIS OF A RECENT ASCAT IMAGE.
   B. TY 19W IS FORECAST TO CONTINUE TRACKING NORTHWARD THROUGH TAU
12 BUT SHOULD GRADUALLY TURN NORTH-NORTHEASTWARD TO NORTHEASTWARD
THROUGH TAU 48 AS IT ROUNDS THE STR AXIS. TY 19W WILL BEGIN EXTRA-
TROPICAL TRANSITION (ETT) NEAR TAU 48 AS IT INTERACTS WITH THE
MIDLATITUDE WESTERLIES AND BAROCLINIC ZONE. THE SYSTEM SHOULD WEAKEN
RAPIDLY AFTER TAU 24 DUE TO INCREASING VWS, COOLER SST AND
INTERACTION WITH LAND. AFTER TAU 60, 19W WILL TRACK OVER THE SEA OF
JAPAN AND WILL COMPLETE ETT NEAR TAU 72 AS IT GAINS FRONTAL
CHARACTERISTICS AND BECOMES EMBEDDED WITHIN STRONG MIDLATITUDE
WESTERLY FLOW. SST VALUES WILL DECREASE TO LESS THAN 24C, WHICH WILL
FURTHER AID IN WEAKENING THE SYSTEM. NUMERICAL MODEL GUIDANCE
REMAINS IN TIGHT AGREEMENT WITH A 70NM SPREAD IN SOLUTIONS AT TAU
48, THEREFORE, THERE IS HIGH CONFIDENCE (LOW UNCERTAINTY) IN THE
JTWC FORECAST TRACK THROUGH TAU 72.
   C. AFTER TAU 72, THIS COLD-CORE EXTRA-TROPICAL LOW WILL
ACCELERATE EAST-NORTHEASTWARD OVER NORTHERN HONSHU. THE SYSTEM IS
STILL EXPECTED TO MAINTAIN GALE-FORCE WINDS. DUE TO THE BROAD NATURE
OF THIS LOW AND THE LARGE SPREAD IN THE NUMERICAL MODELS, THERE IS
LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.//
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