WDPN31 PGTW 250300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 34W (MAN-YI) WARNING NR 22//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON (TY) 34W (MAN-YI), LOCATED APPROXIMATELY 670 NM SOUTHEAST 
OF
KADENA AB, OKINAWA, JAPAN, HAS TRACKED SOUTH-SOUTHWESTWARD AT 02 
KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) SHOWS THE SYSTEM REMAINS IN A QUASI-STATIONARY STATE BUT HAS
MAINTAINED DEEP CENTRAL CONVECTION WITH RAIN BANDS TO THE NORTH
BECOMING MORE ELONGATED AND SHEARED POLEWARD INTO THE STRONG
WESTERLIES. THE INITIAL POSITION IS PLACED OVER THE RAGGED 20-NM EYE
IN THE 242330Z 1KM RESOLUTION HIMAWARI VISIBLE SATELLITE IMAGE WITH
GOOD CONFIDENCE. THE INITIAL INTENSITY OF 80 KNOTS IS HELD SLIGHTLY
LOWER THAN AGENCY DVORAK DVORAK CURRENT INTENSITY ESTIMATES OF
T5.0/90KTS TO REFLECT THE DEGRADED CONVECTIVE STRUCTURE. UPPER-LEVEL
ANALYSIS INDICATES THE SYSTEM IS PRECARIOUSLY IN A LOW (10-15 KNOT)
VERTICAL WIND SHEAR (VWS) AIDED BY A STRONG POLEWARD OUTFLOW.
ALONG-TRACK SEA SURFACE TEMPERATURES AT 29-30 CELSIUS ARE CONDUCIVE.
HOWEVER, OCEAN HEAT CONTENT IS SLOWLY DROPPING, CAUSED BY LOCALIZED
UPWELLING DUE TO THE QS MOTION. THE CYCLONE IS LODGED IN A COL
BETWEEN THE SUBTROPICAL RIDGE (STR) TO THE EAST AND A WEAKER ONE TO
THE WEST.
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TY MAN-YI IS FORECAST TO SLOWLY TURN NORTHWESTWARD AS THE STR
TO THE EAST RE-BUILDS, THEN MORE QUICKLY NORTHWARD AFTER TAU 36 AS IT
ROUNDS THE STR AXIS. THIS TRAJECTORY WILL BE IN CROSS-TRACK WITH THE
STRONG WESTERLIES, CONSEQUENTLY EXPOSING THE CYCLONE TO PROGRESSIVELY
INCREASING VWS (BEGINNING AT 30 KNOTS). THIS, IN ADDITION TO COLD DRY
AIR ADVECTING FROM THE NORTH, WILL CAUSE GRADUAL THEN RAPID DECAY
LEADING TO EVENTUAL DISSIPATION BY TAU 72, POSSIBLY SOONER. THE
NUMERICAL GUIDANCE IS IN AGREEMENT TO THE TRACK PROGRESSION; HOWEVER,
THERE ARE SIGNIFICANT DIFFERENCES IN THE TIMING AND DEGREE OF THE
TURNS, SPANNING OVER 340 NM AT TAU 72, LEADING TO LOW CONFIDENCE IN
THE JTWC TRACK FORECAST THAT IS LAID JUST TO THE LEFT OF THE MODEL
CONSENSUS TO OFFSET AN UNLIKELY TIGHT POLEWARD TURN PROPOSED BY CTCX
AND NVGM.//
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