WDPN31 PGTW 110300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL STORM 18W (CONSON) WARNING NR 
021//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.0N 109.9E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 92 NM EAST OF DA NANG, VIETNAM
   MOVEMENT PAST 6 HOURS: WESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS AN EXPANDING
CENTRAL COLD COVER (CCC) OBSCURING THE LOW-LEVEL CIRCULATION CENTER
(LLCC). RECENT VISIBLE IMAGERY INDICATES THE LLCC IS POSITIONED
ALONG THE EASTERN EDGE OF THIS AREA OF INTENSE CONVECTION. A
102314Z SSMIS 37GHZ IMAGE REVEALS IMPROVED CONVECTIVE ORGANIZATION
WITH CONVECTIVE BANDING WRAPPING INTO A DEFINED LLCC, WHICH
SUPPORTS THE INITIAL POSITION WITH MEDIUM CONFIDENCE. THE INITIAL
INTENSITY OF 50 KTS IS ASSESSED WITH MEDIUM CONFIDENCE AND IS
HEDGED ABOVE THE PGTW DVORAK ESTIMATE, WHICH IS BASED ON THE DVORAK 
CCC METHOD. UPPER-LEVEL ANALYSIS INDICATES A MARGINALLY-FAVORABLE 
ENVIRONMENT WITH MODERATE EASTERLY VERTICAL WIND SHEAR OFFSET BY 
MODERATE WESTWARD OUTFLOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: LOW- TO MID-LEVEL SUBTROPICAL RIDGE
(STR) POSITIONED TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   RJTD: T4.0 - 65 KTS
   RCTP: T3.0 - 45 KTS
   CIMSS ADT: 35 KTS AT 102340Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TS CONSON WILL TRACK WESTWARD TO WEST-
NORTHWESTWARD THROUGH THE FORECAST PERIOD UNDER THE STEERING
INFLUENCE OF THE STR. THE SYSTEM SHOULD MAKE LANDFALL OVER DA NANG,
VIETNAM NEAR TAU 24 WITH RAPID WEAKENING AS THE SYSTEM TRACKS
INLAND OVER THE MOUNTAINOUS TERRAIN. TS 18W IS EXPECTED TO
DISSIPATE BY TAU 72.
 
MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE REMAINS IN TIGHT
AGREEMENT THROUGH TAU 24 BUT DIVERGES AS THE SYSTEM MOVES OVERLAND
LENDING MEDIUM OVERALL CONFIDENCE IN THE FORECAST TRACK. THERE IS A
SLIGHT POSSIBILITY OF FURTHER INTENSIFICATION PRIOR TO LANDFALL BUT
IT IS EXPECTED TO BE MINIMAL DUE TO THE MARGINALLY FAVORABLE
CONDITIONS. OVERALL, THERE IS MEDIUM CONFIDENCE IN THE JTWC
INTENSITY FORECAST.  

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