Tropical Storm SANVU Advisory Sun May 27

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TYPHOON 03W (SANVU) WARNING NR 21//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TYPHOON 03W (SANVU), LOCATED APPROXIMATELY 125 NM SOUTH OF CHICHI
JIMA, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 08 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY CONTINUE TO
INDICATE WEAKENING ORGANIZATION WITH SIGNS OF DEFORMATION ALONG THE
NORTHEAST QUADRANT. THE SAME ANIMATION, CORROBORATED BY A TOTAL
PRECIPITABLE WATER LOOP, SHOWS COLD DRY AIR ENTRAINMENT INTO THE
WESTERN SEMI-CIRCLE, AS EVIDENCED BY THE INFLUX OF STRATOCUMULUS
FIELD. THE INITIAL POSITION IS BASED ON THE ABOVE ANIMATION WITH GOOD
CONFIDENCE AND THE INITIAL INTENSITY IS BASED ON THE HIGH END OF
DVORAK ESTIMATES FROM PGTW, KNES, AND RJTD. UPPER LEVEL ANALYSIS
INDICATES THE CYCLONE IS POLEWARD OF THE RIDGE AXIS IN AN AREA OF
MODERATE (15-20 KT) WESTERLY VERTICAL WIND SHEAR (VWS) AND
UPPER-LEVEL CONVERGENCE. THIS IS DISCERNIBLE ON ANIMATED WATER VAPOR
IMAGERY. TY SANVU IS TRACKING ALONG THE NORTHWESTERN PERIPHERY OF THE
DEEP SUBTROPICAL STEERING RIDGE.
3. FORECAST REASONING.
   A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
   B. TY 03W IS EXPECTED TO ACCELERATE NORTHEASTWARD AND WEAKEN AS IT
TRACKS DEEPER INTO THE PREVAILING WESTERLIES WITH INCREASING VWS OVER
COOLER SST (LESS THAN 25C). CONCURRENTLY, THE SYSTEM WILL BEGIN
EXTRA-TROPICAL TRANSITION (ETT), COMPLETING ETT BY TAU 48 AS IT
BECOMES EMBEDDED IN THE BAROCLINIC ZONE. DUE TO THE TIGHT CLUSTER OF
DYNAMIC
GUIDANCE INCLUDING ENSEMBLE DATA, THERE IS HIGH CONFIDENCE IN THE
FORECAST TRACK.   //
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