WDIO31 PGTW 020300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01B (ONE) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.9N 85.2E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 387 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 03 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
A 02003Z GMI SERIES ALLOWED FOR CONFIDENT FIXING OF THE LOW LEVEL
CIRCULATION CENTER (LLCC), EXPOSING THE LOP-SIDED CONVECTIVE
SHIELD. VIGOROUS VERTICAL WIND SHEAR CONTINUES TO IMPEDE DEVELOPMENT
OF TC 01B. THE SYSTEM IS ASSESSED AT 35KTS BASED ON THE JTWC
DVORAK AND A CIMSS SATCON ESTIMATE OF 38KTS, AVERAGED WITH AN ADT
ASSESSMENT OF 32KTS. TROPICAL CYCLONE 01B CONTINUES TO STRUGGLE
AGAINST THE VIGOROUS NORTHEASTERLY WIND SHEAR. THE BULK OF THE DEEP
CONVECTION IS CONFINED TO THE SOUTHWESTERN QUADRANT BUT SATELLITE
ANIMATION VERIFIES THE EASTERLIES OVER THE TOP OF THE SYSTEM ARE
WRAPPING INTO THE CORE. THE UPSTREAM ENVIRONMENT INDICATES A LITTLE
EASING OF THE WIND SHEAR AND SLIGHTLY WARMING SEA SURFACE
TEMPERATURES ALONG TRACK.

INITIAL WIND RADII BASIS: NO CHANGES SINCE 011204Z ASCAT.

CURRENT STEERING MECHANISM: A MID-LEVEL EXTENSION OF THE
SUBTROPICAL RIDGE OVER THE EASTERN BAY OF BENGAL IS FORCING THE
SYSTEM TOWARDS THE INDIAN COAST.

AGENCY DVORAK AND AUTOMATED FIXES:
   PGTW: T2.5 - 35 KTS
   KNES: T1.5 - 25 KTS
   CIMSS SATCON: 38 KTS AT 012015Z
   CIMSS ADT: 32 KTS AT 020000Z
   CIMSS D-MINT: 28 KTS AT 020033Z
   CIMSS D-PRINT: 33 KTS AT 020100Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG 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: TROPICAL CYCLONE 01B WILL CONTINUE ITS
NORTHWESTERLY TRACK THROUGH AN AREA OF SLIGHTLY WARMER WATERS AND
LOWER WIND SHEAR, SUSTAINING THE SYSTEM THROUGH LANDfALL. IT IS
EXPECTED TO COME ASHORE SOUTH OF BRAHMAPUR, NEAR PALASA. WIND FIELDS
WILL REMAIN UNBALANCED, WITH NO GALE FORCE EASTERLIES LIKELY OVER
THE POLEWARD SEMICIRCLE. 

MODEL DISCUSSION: TRACK GUIDANCE IS EXCELLENT AND IN TIGHT
AGREEMENT AND THE JTWC FORECAST FOLLOWS THE MULTI-MODEL CONSENSUS.
INTENSITY GUIDANCE IS FLAT OR DECLINING, BUT THE FORECAST INTENSITY
IS HELD STEADY DUE TO THE LOWER VWS AND WARMER SEA SURFACE
TEMPERATURES UPSTREAM.

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