Tropical Storm MAN-YI Advisory mar, 27-11

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 34W (MAN-YI) WARNING NR
27//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 34W (MAN-YI), LOCATED APPROXIMATELY 455 NM
SOUTHEAST OF KADENA AB, HAS TRACKED NORTHWESTWARD AT 08 KNOTS OVER
THE PAST SIX HOURS. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
WHICH DEPICTS A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC).
THE MSI LOOP ALSO REVEALS AN ISOLATED AREA OF DEEP CONVECTION THAT
IS DISPLACED ABOUT 80 NM SOUTHEAST OF THE LLCC. THE INITIAL
INTENSITY OF 40 KNOTS IS BASED, WITH FAIR CONFIDENCE, ON DVORAK
ESTIMATES RANGING FROM T2.5-3.5 (35-55 KTS) AND A 260441Z SATCON
ESTIMATE OF 42 KTS. THE ENVIRONMENT, WITH LOW (10-15 KT) VERTICAL
WIND SHEAR (VWS), WARM (27-28 CELSIUS) SEA SURFACE TEMPERATURE
(SST), AND LIMITED OUTFLOW, IS MARGINAL. TS 34W IS TRACKING ALONG
THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR).
3. FORECAST REASONING.
   A. THERE IS NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE
PREVIOUS PROGNOSTIC REASONING MESSAGE.
   B. TS 34W IS FORECAST TO CONTINUE ROUNDING THE STR AXIS AND
ACCELERATE NORTHEASTWARD AFTER TAU 24. THE INTENSITY IS EXPECTED TO
REMAIN 35-40 KNOTS UNDER MARGINAL ENVIRONMENTAL CONDITIONS. AFTER
TAU 24, THE SYSTEM IS EXPECTED TO BEGIN EXTRATROPICAL TRANSITION
(ETT) AS IT ENTERS THE MID-LATITUDE WESTERLIES AND THE BAROCLINIC
ZONE. IT SHOULD COMPLETE ETT BY TAU 48 UNLESS HIGH VWS AND COOL SST
CAUSE IT TO DISSIPATE SOONER. NUMERICAL MODEL GUIDANCE HAS GOOD
CROSS-TRACK AGREEMENT BUT FORWARD SPEED DIFFERENCES RESULT IN
SIGNIFICANT ALONG-TRACK DIFFERENCES, LENDING TO LOW CONFIDENCE IN
THE JTWC TRACK FORECAST.//
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