WDPN33 PGTW 132100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (KOMPASU) WARNING 
NR 015//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.2N 107.6E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 144 NM SOUTHEAST OF HANOI, VIETNAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 13 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY AND RADAR
IMAGERY DEPICTS LIMITED CONVECTIVE BANDING OVER THE WESTERN
PERIPHERY OF THE SYSTEM WITH RAPIDLY WEAKENING DEEP CONVECTION OVER
THE CENTER AS IT RAPIDLY APPROACHES THE SHORE OF VIETNAM. THE 
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED UPON THE EIR 
LOOP, PGTW FIX AND MULTIPLE OBSERVATIONS ALONG THE VIETNAM COAST AND 
HAINAN. THE INITIAL INTENSITY OF 45 KTS IS HEDGED HIGHER THAN 
MULTIPLE AGENCY FIXES, AND IS MORE IN LINE WITH SURFACE OBSERVATION 
AT BACH LONG VI, APPROXIMATELY 55NM NNE OF THE CENTER, WHICH 
REVEALED NORTHERLY WINDS AT 41 KNOTS SUPPORTING THE INITIAL 
INTENSITY ASSESSMENT. ENVIRONMENTAL ANALYSIS REVEALS A MARGINALLY 
FAVORABLE ENVIRONMENT WITH MODERATE TO STRONG EASTERLY VERTICAL WIND 
SHEAR OFFSET BY MODERATE EASTERLY OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE ADJUSTED BY SURFACE
OBSERVATIONS 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
ENTRENCHED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   RJTD: T2.5 - 35 KTS
   RCTP: T2.5 - 35 KTS
   CIMSS ADT: 32 KTS AT 131740Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 20-25 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TS 24W IS FORECAST TO TRACK QUICKLY WESTWARD
UNDER THE DEEP-LAYERED STR ENTRENCHED TO THE NORTH. THE SYSTEM WILL
STEADILY WEAKEN AS IT TRACKS TOWARD VIETNAM WITH MORE RAPID
WEAKENING AFTER TAU 12 WHEN THE SYSTEM MAKES LANDFALL OVER VIETNAM
AND TRACKS INLAND. TS 24W WILL DISSIPATE BY TAU 36.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 12 AND DIVERGES SLIGHTLY OVER LAND WHEN THE SYSTEM
RAPIDLY WEAKENS. INTENSITY GUIDANCE IS IN GOOD AGREEMENT AND 
SUPPORTS THE STEADY WEAKENING TREND.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM//
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