WDIO31 PGTW 270900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03B (MONTHA) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.7N 84.3E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 638 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 03B (MONTHA) HAS EXPERIENCED LITTLE CHANGE IN
STRUCTURE WITH GOOD OUTFLOW AND DEEP CONVECTION DISPLACED TO THE
WEST BY HIGH (25-30 KTS) VERTICAL WIND SHEAR (VWS) AS DEPICTED IN
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY. THE CURRENT
ENVIRONMENTAL CONDITIONS REMAIN MARGINAL, AS WARM (28-29 C) SEA
SURFACE TEMPERATURES (SST) AND GOOD OUTFLOW ARE OFFSET BY
PERSISTENT HIGH VWS. THE INITIAL POSITION IS PLACED WITH HIGH
CONFIDENCE BASED ON A 270430Z METOP-C SCATTEROMETER DATA. THE
INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED
ON THE PREVIOUSLY MENTIONED ASCAT PASS AND AGENCY FIXES LISTED
BELOW.

INITIAL WIND RADII BASIS: A 270430Z METOP-C SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTH 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   CIMSS SATCON: 37 KTS AT 270045Z
   CIMSS ADT: 35 KTS AT 270300Z
   CIMSS AIDT: 30 KTS AT 270500Z
   CIMSS D-MINT: 32 KTS AT 270403Z
   CIMSS D-PRINT: 40 KTS AT 270700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 25-30 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC MONTHA WILL CONTINUE NORTHWESTWARD UNDER
THE INFLUENCE OF A STR CENTERED TO THE NORTH. WHILE FORECASTED SEA
TEMPERATURES AND PERSISTENT POLEWARD AND EQUATORWARD OUTFLOW REMAIN
ADVANTAGEOUS, TC MONTHA WILL STRUGGLE TO INTENSIFY SIGNIFICANTLY
DUE TO FORECASTED VWS. MAXIMUM WIND SPEEDS OF 45 KTS ARE EXPECTED
AROUND TAU 12. AFTER TAU 24, AND JUST PRIOR TO LANDFALL OVER THE
EASTERN INDIAN COAST, THE SYSTEM WILL BEGIN TO GRADUALLY WEAKEN. TC
MONTHA WILL FULLY DISSIPATE OVER LAND BY TAU 72.  

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
WITH A CROSS TRACK SPREAD OF 30 NM UNTIL TAU 24. AFTERWARDS GFS
BREAKS FROM THE OTHER MODELS AND PUSHES THE SYSTEM SLIGHTLY
NORTHEAST UNTIL IT IS JUST SOUTH OF VISAKHAPATNAM, INDIA. THE JTWC
FORECASTED TRACK IS PLACED BETWEEN THE MULTI MODEL CONSENSUS AND
ECMWF DETERMINISTIC GUIDANCE WITH MEDIUM CONFIDENCE. FORECASTED
INTENSITY HAS A 15-20 KT SPREAD WITH THE MODELS AGREEING ON A
DOWNWARD TREND AFTER TAU 24. THE JTWC OFFICIAL FORECAST LIES CLOSE
TO THE MULTI-MODEL CONSENSUS AND IS ASSESSED WITH HIGH CONFIDENCE. 


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