WDIO32 PGTW 281500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05B (DITWAH)     
WARNING NR 007//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 8.6N 80.9E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 945 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 05B CONTINUES TO TRACK SLOWLY NORTHWARD OVER THE 
NORTHEASTERN CORNER OF SRI LANKA. ANIMATED ENHANCED INFRARED (EIR) 
SATELLITE IMAGERY DEPICTS A BROAD, RAGGED LOW-LEVEL CIRCULATION CENTER 
(LLCC), WITH SPIRAL BANDING DISPLACED TO THE NORTH AND WEST OVER 
WATER. A 280743Z GMI 89GHZ MICROWAVE IMAGE REVEALS EXTENSIVE DEEP 
BANDING WRAPPING AROUND A BROAD LLCC. LIMITED SURFACE OBSERVATIONS 
SHOW THE BROAD CIRCULATION BUT ARE SUSTAINED AT LESS THAN 10 KNOTS 
REFLECTING THE WEAK NATURE OF THE LLCC. ALTHOUGH ROBUST POLEWARD 
OUTFLOW CONTINUES TO SUPPORT THE OUTER BANDING, FRICTIONAL EFFECTS AND 
DRY AIR ENTRAINMENT CONTINUE TO SERIOUSLY HINDER CORE DEVELOPMENT. THE 
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EIR 
SATELLITE IMAGERY. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH 
MEDIUM CONFIDENCE BASED ON THE OVERALL WEAK STRUCTURE AND VERY LIMITED 
CIMSS INTENSITY ESTIMATES RANGING FROM 40-41 KNOTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: LOW-LEVEL SUBTROPICAL RIDGE (STR) 
POSITIONED TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   CIMSS D-MINT: 40 KTS AT 280755Z
   CIMSS D-PRINT: 41 KTS AT 281200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 15-20 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: DRY AIR ENTRAINMENT, FRICTIONAL EFFECTS

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 05B WILL TRACK NORTHWARD THROUGH THE
FORECAST PERIOD SKIRTING THE SOUTHEASTERN COAST OF INDIA. THE
SYSTEM WILL MAINTAIN INTENSITY DUE TO PERSISTENT FRICTIONAL EFFECTS
AND DRY AIR ENTRAINMENT THROUGH TAU 36, WITH DISSIPATION
ANTICIPATED BY TAU 48 WHEN THE SYSTEM TRACKS UNDER INCREASING
SOUTHERLY FLOW ALOFT WITH INCREASING VERTICAL WIND SHEAR.  

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT
SUPPORTING THE JTWC TRACK FORECAST WITH MEDIUM CONFIDENCE. THE
280600Z GEFS AND EPS RUNS ARE ALSO IN FAIR AGREEMENT, WITH THE BULK
OF THE SOLUTIONS OVER WATER. THE BULK OF THE RELIABLE INTENSITY
GUIDANCE INDICATES STEADY WEAKENING THROUGH TAU 48. 

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM//
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