Tropical Storm DOKSURI Advisory Wed Jun 27

MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 07W (DOKSURI) WARNING
NR 03//
RMKS//
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.
   TROPICAL STORM (TS) 07W (DOKSURI), LOCATED APPROXIMATELY 360 NM
EAST OF MANILA, PHILIPPINES, HAS TRACKED WEST-NORTHWESTWARD AT 14
KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE
IMAGERY DEPICTS A SLIGHT DIURNAL WEAKENING TREND WITH FRAGMENTED
DEEP CONVECTIVE BANDING WRAPPING INTO THE LOW-LEVEL CIRCULATION
CENTER (LLCC); HOWEVER, A 262229Z TRMM 37 GHZ IMAGE CONTINUES TO
DEPICT AN ORGANIZED LLCC WITH CONVECTIVE BANDING WRAPPING TIGHTLY
INTO THE CENTER. BASED ON THE WELL-DEFINED LLCC, THERE IS GOOD
CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY REMAINS
ASSESSED AT 35 KNOTS BASED ON 35 KNOT DVORAK ESTIMATES FROM PGTW AND
RJTD. UPPER-LEVEL ANALYSIS INDICATES THAT THE LLCC IS LOCATED WITHIN
A GENERALLY FAVORABLE ENVIRONMENT CHARACTERIZED BY GOOD OUTFLOW AND
WEAK (5-10 KNOTS) VERTICAL WIND SHEAR (VWS). ANIMATED WATER VAPOR
IMAGERY REVEALS SOME PRESSURE ON THE NORTHWEST PERIPHERY OF THE
SYSTEM; HOWEVER, EQUATORWARD OUTFLOW REMAINS VIGOROUS AND POLEWARD
OUTFLOW HAS IMPROVED OVER THE PAST 24 HOURS. ADDITIONALLY, SEA
SURFACE TEMPERATURES ARE HIGH (29-30 DEGREES CELSIUS).
3. FORECAST REASONING.
   A. NO CHANGE TO THE FORECAST PHILOSOPHY SINCE THE PREVIOUS
PROGNOSTIC REASONING.
   B. TS 07W IS CURRENTLY STEERING ALONG THE SOUTHWESTERN PERIPHERY
OF AN EAST-WEST ORIENTED DEEP SUBTROPICAL RIDGE (STR), WHICH EXTENDS
WESTWARD TO TAIWAN. THE RECENT 26/12Z LAOG SOUNDING (NORTHERN LUZON)
INDICATES OVERALL DEEP EASTERLY FLOW WITH SOUTHEASTERLY FLOW THROUGH
THE LOW- TO MID-LEVELS, SUPPORTING A WEST-NORTHWESTWARD TRACK. TS
07W IS EXPECTED TO GRADUALLY INTENSIFY TO A PEAK INTENSITY NEAR 60
KNOTS BY TAU 48 DUE TO THE CURRENT AND FORECAST FAVORABLE
CONDITIONS. INTERACTION WITH NORTHERN LUZON WILL SERVE TO SLIGHTLY
WEAKEN OR HINDER DEVELOPMENT NEAR TAU 36 AND, OBVIOUSLY, A CLOSER
TRACK TO LAND WILL SIGNIFICANTLY WEAKEN THE SYSTEM, THEREFORE, THERE
IS MARGINAL CONFIDENCE IN THE PEAK INTENSITY AT THIS POINT. THERE
IS, HOWEVER, HIGH CONFIDENCE IN THE FORECAST TRACK DUE TO THE TIGHT
GROUPING OF THE DYNAMIC MODEL VORTEX TRACKERS AS WELL AS ALL
ENSEMBLE GUIDANCE. NOGAPS HAD BEEN THE SOLE OUTLIER WITH AN
UNREALISTIC POLEWARD TRACK INTO THE STR BUT HAS RECENTLY (26/12Z
RUN) SWITCHED TO A STRAIGHT-RUNNER TRACK.
   C. IN THE EXTENDED PERIOD, TS 07W IS FORECAST TO CONTINUE
TRACKING WEST-NORTHWESTWARD AS IT APPROACHES THE WESTERN EDGE OF THE
STR. DYNAMIC MODEL GUIDANCE IS CONSISTENT IN DEPICTING A SHORT-WAVE
TROUGH DIGGING OVER EASTERN CHINA WHICH SHOULD SERVE TO WEAKEN AND
RETROGRADE THE WESTERN STR, WHICH SHOULD RESULT IN A CONTINUED WEST-
NORTHWESTWARD TRACK OVER OR NEAR HONG KONG. THERE IS LOW CONFIDENCE
IN THE EXTENDED FORECAST DUE TO UNCERTAINTIES IN THE STRENGTH OF THE
AFOREMENTIONED TROUGH AND WESTERN STR. TS 07W IS EXPECTED TO WEAKEN
AS IT APPROACHES HONG KONG DUE TO INCREASING VWS AND LAND
INTERACTION.//
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