Tropical Storm FAXAI Advisory Thu Sep 05

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 14W (FOURTEEN) WARNING
NR 11//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 14W (FOURTEEN), LOCATED APPROXIMATELY 1429 NM
SOUTHEAST OF YOKOSUKA, JAPAN, HAS TRACKED WEST-NORTHWESTWARD AT 10
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY (MSI) DEPICTS A PARTIALLY EXPOSED LOW-LEVEL CIRCULATION
CENTER (LLCC) WITH AN AREA OF DEEP CONVECTION OFFSET TO THE EAST.
THE TUTT CELL, PREVIOUSLY LOCATED TO THE NORTH OF THE LLCC, HAS
SLOWLY TRACKED AWAY FROM TS 14W, ALLOWING FOR THE SYSTEM TO DEVELOP
ENHANCED POLEWARD OUTFLOW. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE USING A 040456Z GMI 37GHZ IMAGE AND MSI. THE INITIAL
INTENSITY REMAINS ASSESSED AT 35 KNOTS ACCORDING TO PERSISTENT
DVORAK CURRENT INTENSITY ESTIMATES OF 2.5 FROM PGTW/KNES AND A
032246Z ASCAT-C PASS DEPICTING 30 TO 35 KNOT WINDS IN THE NORTHEAST
QUADRANT OF THE SYSTEM. WITH THE TUTT CELL MOVING SLOWLY AWAY, THERE
IS A FAVORABLE SHEAR ENVIRONMENT FOR THE SYSTEM WITH VERTICAL WIND
SHEAR VALUES OF APPROXIMATELY 5 TO 15 KNOTS. THERE IS GOOD POLEWARD
AND EQUATORWARD UPPER LEVEL OUTFLOW, HOWEVER, OUTFLOW REMAINS
SLIGHTLY RESTRICTED TO THE WEST. TS 14W IS TRACKING TOWARD THE
NORTHWEST UNDER THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE (STR)
TO THE NORTHEAST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE. THIS FORECAST IS HIGHLY
CONSISTENT WITH THE PREVIOUS JTWC WARNING.
   B. THE STR OVER THE WESTERN NORTH PACIFIC WILL REMAIN THE PRIMARY
STEERING INFLUENCE THROUGH TAU 72. SEA SURFACE TEMPERATURES (29-30
DEGREES CELSIUS) WILL REMAIN FAVORABLE ALONG THE TRACK. THE UPPER-
LEVEL ENVIRONMENT WILL BECOME MORE SUPPORTIVE FOR INTENSIFICATION
AFTER TAU 24. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT, SO THERE
IS HIGH CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK
THROUGH TAU 72.
   C. BEYOND TAU 72, THE STR WILL SHIFT EASTWARD IN RESPONSE TO AN
APPROACHING MIDLATITUDE SHORTWAVE TROUGH, WHICH WILL ENABLE TS 14W
TO RECURVE POLEWARD. FAVORABLE ENVIRONMENTAL CONDITIONS, ALONG WITH
AN ENHANCED POLEWARD OUTFLOW CHANNEL WILL ALLOW TS 14W TO INTENSIFY
TO 90 KNOTS BY TAU 96. RAPID WEAKENING IS ANTICIPATED AFTER TAU 96
AS THE SYSTEM TRACKS ACROSS THE JAPAN ALPS. DYNAMIC MODEL GUIDANCE
DIVERGES WITH A LARGE SPREAD IN SOLUTIONS DUE TO MAJOR DIFFERENCES
IN TRACK SPEED AND THE TIMING OF THE RECURVE. THEREFORE, THERE IS
LOW CONFIDENCE IN THIS PORTION OF THE JTWC FORECAST TRACK.//
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