WDIO32 PGTW 231500
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 06B (SIX) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.4N 87.4E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 341 NM SOUTHWEST OF CHITTAGONG
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS
TROPICAL CYCLONE (TC) 06B (SIX) PERSISTING IN A FAVORABLE
ENVIRONMENT OVER THE PAST SIX HOURS. THE LOW LEVEL CIRCULATION
CENTER (LLCC) REMAINS COMPLETELY OBSCURED BY CENTRALIZED AND
INTERMITTENTLY FLARING CONVECTION THAT APPEARS TO BE CYCLONICALLY
CIRCUMNAVIGATING THE LLCC. ONGOING DEEP CONVECTION CONTINUES
THROUGHOUT A 275NM LONG QUASILINEAR BAND NORTHEAST OF THE LLCC. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON
METEOSAT-9 IR-BD ANIMATED IMAGERY AND A 231201Z METEOSAT-9 IR-BD
IMAGE. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM
CONFIDENCE BASED ON A THE SUBJECTIVE AND OBJECTIVE INTENSITY
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: STR EAST OF TC 06B

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T2.0 - 30 KTS
   CIMSS ADT: 41 KTS AT 231200Z
   CIMSS AIDT: 34 KTS AT 231200Z
   CIMSS DPRINT: 44KTS AT 231200Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE POLEWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 06B IS FORECAST TO TRACK NORTHEASTWARD OVER
THE NEXT 48 HOURS. THROUGH TAU 12, THE SYSTEM IS LIKELY TO TAKE 
ADVANTAGE OF A FAVORABLE ENVIRONMENT AND GRADUALLY INTENSIFY.  AFTER 
TAU 12, VERTICAL WIND SHEAR INCREASES (45KTS BY TAU 48). 
ADDITIONALLY, A SHORTWAVE TROUGH IS FORECAST TO DIG SOUTH FROM THE 
NORTH OVER THE NORTHERN BAY OF BENGAL (TAU 6 TO TAU 18) AND IS 
ANTICIPATED TO RAPIDLY WEAKEN TC 06B WITH THE INTRODUCTION OF DEEP-
LAYER WESTERLY FLOW. COMPLETE DISSIPATION IS FORECAST TO OCCUR PRIOR 
TO TAU 48.

MODEL DISCUSSION: GLOBAL NUMERICAL MODELS ARE IN GOOD AGREEMENT
THAT TC 06B WILL TRACK NORTHEASTWARD THROUGH TAU 48, WITH THE JTWC
CONSENSUS SHOWING A CROSS-TRACK SPREAD OF 43NM AT TAU 48. THERE IS,
HOWEVER, SIGNIFICANT UNCERTAINTY PRESENTED IN TRACK SPEED, WITH AN
ALONG-TRACK SPREAD OF 258NM BETWEEN MOGREPS AND NAVGEM. THIS
UNCERTAINTY CONTRIBUTES TO A TRACK FORECAST CONFIDENCE OF MEDIUM.
INTENSITY GUIDANCE IS IN VERY GOOD AGREEMENT THAT TC 06B WILL
CONTINUE TO GRADUALLY INTENSIFY TO NEAR 45 KTS BY TAU 12, FOLLOWED
BY A WEAKENING TREND TO 15 KTS BY TAU 48. GIVEN THE VARIABILITY IN
TRACK SPEED, THE FORECAST CONFIDENCE FOR INTENSITY IS ALSO MEDIUM.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: MEDIUM//
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