WDIO32 PGTW 271500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05B (DITWAH)     
WARNING NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 7.6N 81.7E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 980 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 16 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A BROAD
LOW-LEVEL CIRCULATION, WITH DEEP CONVECTIVE BANDING OVER THE NORTHERN 
AND WESTERN QUADRANTS WRAPPING INTO A RAGGED, DEFINED LOW-LEVEL 
CIRCULATION CENTER (LLCC). A 271047Z SSMIS 37GHZ MICROWAVE IMAGE SHOWS 
CONVECTIVE BANDING WRAPPING AROUND THE NORTHERN SEMICIRCLE, WITH A 
BROAD, WEAK LLCC. MULTIPLE SURFACE OBSERVATIONS SHOW A BROAD 
CIRCULATION AND GENERALLY SUPPORT THE INITIAL POSITION OVERLAND. THE 
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON EIR 
SATELLITE IMAGERY AND THE SSMIS IMAGE. ENVIRONMENTAL CONDITIONS ARE 
MARGINALLY FAVORABLE, WITH MODERATE RADIAL OUTFLOW, LOW VERTICAL WIND 
SHEAR OFFSET BY FRICTIONAL EFFECTS. THE INITIAL INTENSITY IS ASSESSED 
WITH HIGH CONFIDENCE BASED ON PERSISTENCE.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   CIMSS ADT: 39 KTS AT 271200Z
   CIMSS AIDT: 31 KTS AT 271100Z
   CIMSS D-MINT: 44 KTS AT 271047Z
   CIMSS D-PRINT: 41 KTS AT 271200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 10-15 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE RADIAL

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 05B IS FORECAST TO TRACK
SLOWLY POLEWARD ALONG THE WESTERN PERIPHERY OF THE LOW-LEVEL STR
BUILDING TO THE EAST AND NORTHEAST. AFTER TAU 96, TC 05B IS
EXPECTED TO TURN NORTHEAST AS IT ROUNDS THE NORTHWEST PERIPHERY OF
THE LOW-LEVEL STR TOWARD A BREAK IN THE STR. DUE TO THE TRACK ALONG
THE COAST OF SRI LANKA AND JUST EAST OF SOUTHEASTERN INDIA, THE
SYSTEM WILL INTENSIFY SLOWLY THROUGH TAU 48. AFTER TAU 48,
UPPER-LEVEL CONDITIONS WILL DEGRADE, WITH INCREASING SOUTHERLIES
AND STRONG (25-30 KNOTS) VERTICAL WIND SHEAR ASSOCIATED WITH A DEEP
UPPER-LEVEL TROUGH DIGGING INTO THE ARABIAN SEA AND INDIA. THE
SYSTEM SHOULD DISSIPATE NEAR TAU 96 UNDER STRONG SOUTHWESTERLY
UPPER-LEVEL FLOW. 

MODEL DISCUSSION: DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT ON
THE POLEWARD TRACK THROUGH TAU 72, WITH INCREASING UNCERTAINTY IN
THE TRACK AFTER TAU 72. THE 270600Z GEFS AND EPS RUNS SHOW
SIGNIFICANT UNCERTAINTY THROUGH THE ENTIRE FORECAST PERIOD, WITH
THE BULK OF THE GUIDANCE SUPPORTING A GENERALLY POLEWARD TRACK EAST
OF THE SOUTHEAST INDIA COAST. RELIABLE INTENSITY GUIDANCE IS IN
GOOD AGREEMENT AND SUPPORTS THE JTWC INTENSITY FORECAST WITH MEDIUM
CONFIDENCE.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN