Tropical Storm SANVU Advisory Sun May 27

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 03W (SANVU) WARNING NR 24//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 03W (SANVU), LOCATED APPROXIMATELY 160 NM EAST
OF CHICHI JIMA, JAPAN, HAS TRACKED EAST-NORTHEASTWARD AT 14 KNOTS
OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
(MSI) DEPICTS AN EXPOSED, ELONGATED LOW-LEVEL CIRCULATION CENTER
(LLCC) WITH ISOLATED BURSTS OF DEEP CONVECTION OVER THE EASTERN
SEMI-CIRCLE. MSI ALSO SHOWS THAT THE LLCC HAS BEGUN TO INTERACT WITH
A BROAD BAROCLINIC ZONE TO THE NORTH AND COOL (DRY) AIR STRATOCUMULUS
IS EVIDENT OVER THE WESTERN SEMI-CIRCLE. A 262059Z CORIOLIS 37H GHZ
IMAGE DEPICTS A WELL-DEFINED, SHALLOW LLCC WITH TIGHTLY-CURVED
CONVECTIVE BANDING WRAPPING INTO THE CENTER. THEREFORE, THERE IS GOOD
CONFIDENCE IN THE CURRENT POSITION AND RECENT TRACK. UPPER-LEVEL
ANALYSIS INDICATES THAT THE LLCC IS LOCATED WITHIN THE MIDLATITUDE
WESTERLY FLOW AND IS UNDER STRONG VERTICAL WIND SHEAR (VWS) OF 25-30
KNOTS. THE CURRENT INTENSITY IS ASSESSED AT 50 KNOTS BASED ON AN
AVERAGE OF DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM 45 TO 55
KNOTS FROM PGTW AND KNES. TS 03W IS TRACKING WITHIN RELATIVELY WEAK
WESTERLY FLOW LOCATED NORTH OF THE SUBTROPICAL STEERING RIDGE.
3. FORECAST REASONING.
   A. NO CHANGE IN THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING BULLETIN.
   B. TS 03W IS FORECAST TO ACCELERATE ALONG THE NORTHERN PERIPHERY
OF THE SUBTROPICAL STEERING RIDGE THROUGH THE FORECAST PERIOD. TS 03W
WILL CONTINUE TO WEAKEN DUE TO INCREASING VWS (GREATER THAN 40 KNOTS)
AND COLDER SST (LESS THAN 22C). THE SYSTEM HAS CLEARLY COMMENCED
EXTRA-TROPICAL TRANSITION (ETT) AND SHOULD COMPLETE ETT BY TAU 24.
THE SYSTEM IS EXPECTED TO TRANSITION INTO A GALE-FORCE EXTRA-TROPICAL
LOW. DYNAMIC GUIDANCE HAS REMAINED IN TIGHT AGREEMENT INCLUDING
ENSEMBLE DATA, THEREFORE, THERE IS HIGH CONFIDENCE IN THE FORECAST
TRACK.//
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