WDIO31 PGTW 040900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 08B (MICHAUNG)   
WARNING NR 006//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.4N 81.1E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 691 NM SOUTHWEST OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS IMPROVED
CONVECTIVE ORGANIZATION WITH DEEP CONVECTION AND UPPER-LEVEL CLOUD
COVER OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC). FORTUNATELY, 
RADAR IMAGERY DEPICTS CONVECTIVE BANDING WRAPPING INTO A DEFINED, 
BROAD LLCC, WHICH SUPPORTS THE INITIAL POSITION WITH MEDIUM 
CONFIDENCE. A 040418Z MHS 89 GHZ MICROWAVE IMAGE ALSO REVEALS 
EXTENSIVE DEEP CONVECTIVE BANDING WRAPPING INTO THE SOUTHERN QUADRANT 
SUPPORTING THE INTENSITY ASSESSMENT OF 55 KNOTS. DVORAK INTENSITY 
ESTIMATES INDICATE A WIDE RANGE OF VALUES FROM T3.5 (55 KNOTS) TO 
T4.5 (77 KNOTS). CIMSS OBJECTIVE ESTIMATES SHOW A MORE CONSISTENT, 
REALISTIC RANGE OF INTENSITY VALUES FROM 52 TO 53 KNOTS, WHICH IS 
ALSO CONSISTENT WITH THE CURRENT CONVECTIVE STRUCTURE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR)
POSITIONED TO THE NORTHEAST.   

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T4.5 - 77 KTS
   CIMSS ADT: 53 KTS AT 040600Z
   CIMSS AIDT: 52 KTS AT 040700Z
   CIMSS DPRINT: 52 KTS AT 040700Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 0-5 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

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 (TC) 08B IS FORECAST TO TRACK
POLEWARD ALONG THE WESTERN PERIPHERY OF A NORTH-SOUTH ORIENTED STR
THROUGH TAU 48. THE SYSTEM SHOULD INTENSIFY SLIGHTLY OVER THE NEXT
12 HOURS DUE TO THE FAVORABLE ENVIRONMENTAL CONDITIONS, WITH A PEAK
OF 60 KNOTS ANTICIPATED BY TAU 12. AFTER TAU 12, TC 08B WILL
GRADUALLY WEAKEN AS IT SKIRTS THE EASTERN COAST OF INDIA WITH
LANDFALL EXPECTED NEAR TAU 30. AFTER LANDFALL, THE SYSTEM WILL
RAPIDLY WEAKEN AND DISSIPATE AS IT TRACKS INLAND AND RECURVES
NORTHEASTWARD, INTERACTING WITH THE MIDLATITUDE WESTERLIES AND
INCREASING VERTICAL WIND SHEAR. THE REMNANTS COULD POSSIBLY TRACK
OVER THE NORTHERN BAY OF BENGAL AFTER DAY 4 BUT ARE NOT EXPECTED TO
REGENERATE DUE TO UNFAVORABLE CONDITIONS AND STRONG UPPER-LEVEL
WESTERLIES.       

MODEL DISCUSSION: THERE IS SOME UNCERTAINTY IN THE EXACT TRACK AND
LANDFALL LOCATION, HOWEVER BOTH DETERMINISTIC AND PROBABILISTIC
GUIDANCE ARE IN GOOD AGREEMENT THROUGH TAU 36. THERE IS CURRENTLY A
60 NM TO 80 NM CROSS-TRACK SPREAD IN NUMERICAL GUIDANCE FROM TAU 24
TO TAU 36. AFTER TAU 36, GUIDANCE DIVERGES WITH INCREASING
UNCERTAINTY IN THE JTWC TRACK FORECAST. THEREFORE, THERE IS MEDIUM
OVERALL CONFIDENCE IN THE JTWC TRACK FORECAST. THE JTWC INTENSITY
FORECAST HAS WORKED OUT WELL THUS FAR AND CONTINUES TO INDICATE A
PEAK INTENSITY OF 60 KNOTS, WHICH IS SUPPORTED BY RELIABLE
INTENSITY GUIDANCE INCLUDING THE HAFS-A AND COAMPS-TC MESOSCALE
MODEL GUIDANCE.  

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