WDIO32 PGTW 091500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03B (THREE)      
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 19.9N 91.7E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 144 NM SOUTH OF CHITTAGONG
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 02 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A 
PARTIALLY-EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH DEEP CONVECTION
FLARING OVER THE WESTERN SEMICIRCLE. A 091004Z SSMIS 91GHZ COLOR
COMPOSITE MICROWAVE IMAGE REVEALS A LINEAR BAND OF DEEP CONVECTION
SHEARING WESTWARD WITH A WEAKLY DEFINED LLC NEAR THE EASTERN EDGE OF 
THE BAND. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED 
ON THE EIR IMAGERY AND THE SSMIS IMAGE. ENVIRONMENTAL ANALYSIS 
INDICATES A MARGINALLY UNFAVORABLE ENVIRONMENT WITH HIGH (25-30 KNOTS) 
EASTERLY VERTICAL WIND SHEAR AND BROAD DIFFLUENCE ALOFT. THE INITIAL 
INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A 
RECENT 090355Z ASCAT-B BULLSEYE IMAGE SHOWING A SWATH OF 35 TO 40 KNOT 
WINDS OVER THE SOUTHERN SEMICIRCLE. DVORAK INTENSITY ESTIMATES REMAIN 
TOO LOW HOWEVER THE CIMSS ADT ESTIMATE OF 41 KNOTS IS SUPPORTIVE.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: LOW-LEVEL STEERING RIDGE POSITIONED TO
THE SOUTHEAST WITH FLOW ENHANCED BY THE SOUTHWEST MONSOON

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   DEMS: T1.0 - 25 KTS
   CIMSS ADT: 41 KTS AT 091130Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 20-25 KTS
   SST: 30-31 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: TC 03B IS FORECAST TO TRACK NORTHEASTWARD TO
NORTH-NORTHEASTWARD ALONG THE NORTHWESTERN FLANK OF THE STEERING
FLOW THROUGH THE FORECAST PERIOD. DUE TO THE MARGINALLY UNFAVORABLE
ENVIRONMENTAL CONDITIONS, THE SYSTEM IS NOT EXPECTED TO INTENSIFY
BUT SHOULD STEADILY WEAKEN AS IT APPROACHES THE MYANMAR COAST WITH
DISSIPATION OCCURRING WITHIN THE NEXT 24 HOURS.

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS VERY LIMITED WITH
HWRF, ECMWF AND GFS SUPPORTING THE JTWC FORECAST TRACK INTO
MYANMAR. THE 090000Z GFS ENSEMBLE (GEFS) SHOWS THE BULK OF
SOLUTIONS TRACKING THE SYSTEM INTO MYANMAR WITH NO SIGNIFICANT
DEVELOPMENT. THE 081800Z ECMWF ENSEMBLE (EPS) IS MORE LIMITED WITH
A SPARSE SET OF SOLUTIONS TRACKING THE WEAK SYSTEM NORTHEASTWARD TO
NORTH-NORTHEASTWARD. DUE TO THE LACK OF GUIDANCE, THE CONFIDENCE IN
BOTH THE JTWC TRACK AND INTENSITY FORECAST IS MEDIUM.

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