WDIO31 PGTW 012100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 01B (ONE) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.7N 85.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 390 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS
NORTHEASTERLY SHEAR SHOVING THE DEEP CONVECTION AWAY FROM THE LOW
LEVEL CIRCULATION CENTER (LLCC), IMPEDING DEVELOPMENT OF TC 01B. AN 
EARLIER SCATTEROMETRY PASS AND A CURRENT JTWC DVORAK USING THE SHEAR
TECHNIQUE AND NETTING A T2.0 GAVE AN OVERALL ASSESSMENT OF 30-35KTS
FOR THE SYSTEM, BUT RECENT SATELLITE ANIMATION SHOWS THE LLCC
TUCKING BACK UNDER THE CONVECTION AND THE MOST RECENT DVORAK CAME
OUT AT T2.5, SUPPORTING THE CURRENT INTENSITY. THE SCATTEROMETRY
ALSO SHOWS A LOP-SIDED SYSTEM WITH ALL THE WINDFIELDS EXCEEDING
30KT LYING OVER ONLY THE SOUTHERN SEMICIRCLE. THE UPSTREAM 
ENVIRONMENT BETWEEN THE SYSTEM AND THE COAST IS MODERATELY MORE 
FAVORABLE. INITIAL WIND RADII BASIS:  A 011421Z SCATTEROMETRY IMAGE.

CURRENT STEERING MECHANISM: A MID AND UPPER LEVEL EXTENSION 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
   DEMS: T1.5 - 25 KTS
   CIMSS SATCON: 40 KTS AT 011926Z
   CIMSS ADT: 31 KTS AT 011800Z
   CIMSS AIDT: 28 KTS AT 011700Z
   CIMSS D-PRINT: 29 KTS AT 011900Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG EQUATORWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: LOW
   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 TRACK THROUGH AN
AREA OF SLIGHTLY WARMER WATERS AND LOWER WINDSHEAR TO THE NORTH,
KEEPING THE SYSTEM VIABLE THROUGH LANDFALL. IT IS EXPECTED TO COME
ASHORE SOUTH OF BRAHMAPUR, NEAR PALASA. WINDFIELDS 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: HIGH
   INTENSITY 00-72 HR: MEDIUM//
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