Advisories

WDIO31 PGTW 272100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02B (ARNAB) WARNING NR 
008//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.4N 81.6E
   INITIAL INTENSITY: 100 KTS
   GEOGRAPHIC REFERENCE: 535 NM SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: XX FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS THE
CENTER OF TROPICAL CYCLONE (TC) 02B JUST ONSHORE OF THE SOUTHEAST
INDIAN COAST. THE EYE RAPIDLY ERODED OVER THE LAST FEW HOURS AS THE
SYSTEM WAS MAKING LANDFALL. A PARTIAL 271621Z METOP-C ASCAT PASS
SHOWED A RELATIVELY COMPACT FIELD OF GALE FORCE WINDS JUST OFF
SHORE. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED
ON THE CENTER OF ROTATION IN EIR IMAGERY. THE INITIAL INTENSITY OF
100 KTS IS ASSESSED WITH LOW CONFIDENCE BASED ON THE EFFECT OF
RAPID DECAY FROM LAND INTERACTION. THE ENVIRONMENT IS HIGHLY
UNFAVORABLE BECAUSE OF THE POSITION OVER LAND, ALTHOUGH A ROBUST
POLEWARD OUTFLOW CHANNEL COULD SUPPORT A SLOWER WEAKENING TREND IN
THE SHORT TERM.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHWESTERN FLANK OF A DEEP-LAYER
SUBTROPICAL RIDGE (STR) CENTERED OVER EXTREME SOUTHERN CHINA.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: NO CURRENT ESTIMATE
   DEMS: T4.0 - 65 KTS
   CIMSS ADT: 117 KTS AT 271800Z
   CIMSS AIDT: 109 KTS AT 271800Z
   CIMSS D-MINT: 108 KTS AT 271726Z
   CIMSS D-PRINT: 118 KTS AT 271800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 15-20 KTS
   SST: OVER LAND
   OUTFLOW: STRONG POLEWARD
   OTHER FACTORS: CENTER OF THE SYSTEM IS JUST OVER LAND

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: FOLLOWING THE RECENT LANDFALL, TC 02B MAY HAVE
A BRIEF PERIOD OF QUASI-STATIONARY MOTION ALONG THE COAST OF INDIA
BEFORE THE STEERING RIDGE BEGINS TO STEER IT NORTHWARD BY TAU 12
AND THROUGH THE REMAINDER OF THE FORECAST PERIOD. RAPID DECAY OVER
LAND IS FORECAST, WITH DISSIPATION BY TAU 36.  

MODEL DISCUSSION: MODEL TRACK GUIDANCE IS IN GOOD AGREEMENT ABOUT
THE IMMINENT NORTHWARD TURN BY TAU 12 AND THE CONTINUED NORTHWARD
TRACK UNTIL DISSIPATION. SURFACE FIELDS IN GFS AND ECMWF STILL
DEPICT A SHORT PERIOD OF QUASI-STATIONARY MOTION ALONG THE COAST AS
A RESULT OF DYNAMIC INTERACTION WITH INVEST 90B TO THE EAST. IT
REMAINS TO BE SEEN IF THOSE DYNAMICS WILL IMPART ANY SIGNIFICANT
INFLUENCE ON THE TRACK OF 02B. INTENSITY GUIDANCE IS VERY TIGHTLY
PACKED, ALL DEPICTING THE RAPID DECAY SCENARIO.

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