Tropical Storm MITAG Advisory Tue Oct 01

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 19W (MITAG) WARNING NR 016//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 19W (MITAG), LOCATED APPROXIMATELY 530 NM SOUTHWEST
OF SASEBO, JAPAN, HAS TRACKED NORTHWARD AT 12 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A FULLY-
EXPOSED, WELL-DEFINED LOW-LEVEL CIRCULATION CENTER DE-COUPLED FROM
THE DEEP CONVECTION TO THE NORTH. THIS IMAGERY SUPPORTS THE CURRENT
POSITION WITH HIGH CONFIDENCE. ANIMATED ENHANCED INFRARED SATELLITE
IMAGERY INDICATES RAPIDLY DECAYING DEEP CONVECTION SHEARING
NORTHWARD DUE TO MODERATE TO STRONG (20-30 KNOTS) SOUTHERLY VERTICAL
WIND SHEAR (VWS). THE INITIAL INTENSITY IS ASSESSED AT 75 KNOTS
BASED ON THE LOWER END OF DVORAK CURRENT INTENSITY ESTIMATES RANGING
FROM 4.5 TO 5.0 (77 TO 90 KNOTS). SST VALUES HAVE DECREASED SLIGHTLY
TO 25-26C. 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.
   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 36 AS IT INTERACTS WITH THE
MIDLATITUDE WESTERLIES AND BAROCLINIC ZONE. THE SYSTEM SHOULD WEAKEN
RAPIDLY 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
40NM 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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