WDPN33 PGTW 131500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 24W (KOMPASU) WARNING 
NR 014//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.4N 109.0E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 199 NM EAST-SOUTHEAST OF HANOI, VIETNAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 16 KTS

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE AND RADAR IMAGERY DEPICTS
LIMITED CONVECTIVE BANDING OVER THE WESTERN PERIPHERY OF THE SYSTEM
WITH RAPIDLY WEAKENING DEEP CONVECTION OVER THE CENTER. A 131205Z
GMI 37GHZ MICROWAVE IMAGE INDICATES CURVED SHALLOW BANDING JUST
WEST OF HAINAN ISLAND, WHICH SUPPORTS THE INITIAL POSITION WITH
MEDIUM CONFIDENCE. THE INITIAL INTENSITY OF 45 KTS IS ASSESSED WITH
MEDIUM CONFIDENCE BASED ON THE RJTD DVORAK INTENSITY ESTIMATE.
ADDITIONALLY, SURFACE OBSERVATIONS FROM BACH LONGVI, APPROXIMATELY
83NM WNW OF THE CENTER, REVEAL NORTHERLY WINDS AT 41 KNOTS WHICH
ALSO SUPPORTS THE INITIAL INTENSITY ASSESSMENT. ENVIRONMENTAL
ANALYSIS REVEALS A MARGINALLY FAVORABLE ENVIRONMENT WITH STRONG
EASTERLY VERTICAL WIND SHEAR OFFSET BY MODERATE POLEWARD AND
EQUATORWARD 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: NO CURRENT ESTIMATE
   RJTD: T3.0 - 45 KTS
   RCTP: T3.5 - 55 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 25-30 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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 48.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT
THROUGH TAU 12 BUT DIVERGES 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: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
NNNN