WDIO31 PGTW 232100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05B (SITRANG) WARNING 
NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.7N 88.8E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 376 NM SOUTH-SOUTHWEST OF CHITTAGONG,
BANGLADESH
   MOVEMENT PAST 6 HOURS: NORTH-NORTHEASTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 12 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A VERY
LARGE CYCLONE (620NM+ DIAMETER) SPANNING MOST OF THE BAY OF BENGAL
WITH BROAD AND DEEP RAIN BANDS AHEAD AND TO THE RIGHT OF A WIDE
CENTRAL DENSE OVERCAST THAT IS OBSCURING THE LOW LEVEL CIRCULATION.
THE INITIAL POSITION AND INTENSITY ARE EXTRAPOLATED FROM THE
231451Z AND 231539Z ASCAT BULLSEYE PASSES AND SUPPORTED BY AGENCY
AND AUTOMATED DVORAK FIXES WITH CONGRUENT WIND SPEED VALUES.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA.

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T2.5 - 35 KTS
   DEMS: T2.0 - 30 KTS
   CIMSS ADT: 35 KTS AT 231515Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-15 KTS
   SST: 29-30 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 SITRANG WILL CONTINUE ON ITS
NORTH-NORTHEASTWARD TRACK ALONG THE WESTERN EDGE OF THE STR AND
MAKE LANDFALL OVER BANGLADESH, APPROXIMATELY 50NM TO THE WEST OF
CHITTAGONG, A FEW HOURS AFTER TAU 24. THE FAVORABLE ENVIRONMENT
WILL FUEL AN INTENSIFICATION TO A PEAK OF 50KTS BY TAU 12.
AFTERWARD, INCREASING VWS WILL ERODE THE SYSTEM DOWN TO 45KTS PRIOR
TO LANDFALL, THEN MORE RAPIDLY TO 30KTS BY TAU 36 WITH THE ADDITION
OF LAND INTERACTION. 

MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT WITH
VERY MINIMAL AND GRADUAL SPREAD TO 55NM BY TAU 36, LENDING HIGH
CONFIDENCE IN THE JTWC TRACK FORECAST. 

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