WDIO31 PGTW 080300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02B (TWO) WARNING NR 
004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.1N 89.0E
   INITIAL INTENSITY: 60 KTS
   GEOGRAPHIC REFERENCE: 691 NM SOUTH OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 22 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A FAST
GROWING SYSTEM THAT SPANS 500NM WITH A SYMMETRICAL COLD DENSE 
OVERCAST (CDO) THAT IS ABOUT TO REVEAL AN EYE. RAIN BANDS FROM THE 
NORTHERN AND WESTERN PERIPHERIES ARE WRAPPING IN TIGHTER. THE MSI 
LOOP ALSO SHOWS PRESSURE ALONG THE EASTERN SIDE, AN INDICATION OF 
MODERATE EASTERLY VERTICAL WIND SHEAR (VWS). DESPITE THE SHEAR, THE 
CDO CONTINUED TO DEEPEN AND EXPAND OVER THE LAST SIX HOURS. THE
INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A
DISCERNIBLE LOW LEVEL CIRCULATION FEATURE IN THE 072242Z SSMIS
91GHZ IMAGE. THE INITIAL INTENSITY IS AVERAGED FROM AGENCY AND
AUTOMATED DVORAK ESTIMATES AND REFLECTS THE SIGNIFICANT 6-HR
IMPROVEMENT AND CONSISTENT WITH A FORMATIVE EYE.

INITIAL WIND RADII BASIS: PERSISTENCE FROM RECENT SCATTEROMETER
DATA. 

CURRENT STEERING MECHANISM: WESTERN PERIPHERY OF A SUBTROPICAL
RIDGE (STR) TO THE NORTHEAST AND EAST.


AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   CIMSS SATCON: 60 KTS AT 071958Z
   CIMSS ADT: 65 KTS AT 072115Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 31-32 CELSIUS
   OUTFLOW: STRONG WESTWARD

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 02B IS EXPECTED TO CONTINUE TRACKING
NORTHWESTWARD ALONG THE PERIPHERY OF THE STR THROUGH TAU 36 UNDER
THE STEERING INFLUENCE OF THE ST. THE FAVORABLE CONDITIONS WILL
CARRY THROUGH TAU 24 AND FUEL A STEADY INTENSIFICATION TO PEAK OF
70KTS. AFTERWARD THE SYSTEM WILL WEAKEN STEADILY DUE TO INCREASING
VWS ASSOCIATED WITH THE PREVAILING WESTERLIES AND COOL DRY AIR FROM
THE NORTH STREAMS INTO THE LLC. AFTER TAU 36, THE CYCLONE WILL TURN
MORE NORTHWARD THEN NORTHEASTWARD AS IT ROUNDS THE STR AXIS AS THE
STR RECEDES IN RESPONSE TO AN APPROACHING MID-LATITUDE SHORTWAVE.
BY TAU 120, TC 02B WILL BE REDUCED TO 35KTS.

MODEL DISCUSSION: THE MAJORITY OF THE NUMERICAL MODELS ARE IN FAIR
AGREEMENT WITH THE FORECAST TRACK WITH THE SOLE EXCEPTION OF NAVGEM
WHICH CONTINUES TO TRACK THE VORTEX WEST-NORTHWESTWARD INTO
SOUTHERN INDIA, A SIGNIFICANT DEVIATION FROM THE FORECAST TRACK OF
OVER 360NM AT TAU 72. IN VIEW OF THIS, THERE IS MEDIUM CONFIDENCE
IN THE JTWC FORECAST TRACK THAT IS LAID TO THE RIGHT OF CONSENSUS
TO OFFSET NAVGEM. THERE IS ALSO MEDIUM CONFIDENCE IN THE FORECAST
INTENSITIES THAT ARE HELD SLIGHTLY HIGHER THAN CONSENSUS TOWARD THE
MID PORTION OF THE FORECAST, INCLUDING PEAK INTENSITY.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: MEDIUM
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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