WDPN33 PGTW 140300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (KOMPASU) WARNING 
NR 017//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.2N 107.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 141 NM SOUTHEAST OF HANOI, VIETNAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 07 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) AND RADAR IMAGERY 
DEPICTS CONVECTIVE BANDING OVER VIETNAM WITH THE PARTIALLY EXPOSED
LLC OVER GULF OF TONKIN. THE CONVECTION IS DYING RAPIDLY OVER THE
RUGGED TERRAIN OF VIETNAM AND LAOS. THE INITIAL POSITION IS PLACED
WITH HIGH CONFIDENCE BASED UPON THE MSI LOOP, AND MULTIPLE
OBSERVATIONS ALONG THE VIETNAM COAST. THE INITIAL INTENSITY OF 35
KTS IS HEDGED SLIGHTLY HIGHER THAN MULTIPLE AGENCY FIXES DUE TO
MOST RECENT OBSERVATIONS AT BACH LONG VI, VIETNAM. ENVIRONMENTAL
ANALYSIS REVEALS A MARGINALLY UNFAVORABLE ENVIRONMENT WITH WEAK
EASTERLY OUTFLOW AND MODERATE EASTERLY VERTICAL WIND SHEAR,
INDICATING THE OVERALL WEAKENING TREND OF THE SYSTEM.

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: T2.0 - 30 KTS
   RJTD: T2.0 - 30 KTS
   RCTP: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: WEAK WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 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 IS EXPECTED TO MAKE LANDFALL SOUTH OF HANOI,
VIETNAM. TS 24W WILL DISSIPATE BY TAU 24 IF NOT SOONER.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 12 AND DIVERGES RAPIDLY 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: LOW//
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