WDPN31 PGTW 270300
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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