WDIO31 PGTW 232100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03B (DANA) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 18.1N 88.7E
   INITIAL INTENSITY: 55 KTS
   GEOGRAPHIC REFERENCE: 271 NM SOUTH OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: NORTH-NORTHWESTWARD AT 08 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED IMAGERY (EIR) AND A 231513Z AMSU-B 89
GHZ MICROWAVE IMAGE DEPICT SYMMETRIC, SPIRAL BANDING OF LOW CLOUDS 
COVERED BY A CENTRAL DENSE OVERCAST (CDO) FEATURE, WITH FLARING, DEEP 
CONVECTION IN THE SOUTHWEST QUADRANT OF THE CIRCULATION. OUTFLOW IS 
VERY CONDUCIVE FOR DEVELOPMENT WITH TRANSVERSE BANDING EVIDENT 
RADIALLY AND DUAL CHANNEL OUTFLOW SUPPORT FROM AN UPPER LEVEL 
ANTICYCLONE TO THE NORTHEAST AND THE BROAD TROPICAL EASTERLY JET 
(TEJ) TO THE SOUTH. A TIGHTER GRADIENT IN THE CLOUD TOP TEMPERATURES 
ON THE EAST AND PARTICULARLY NORTHEAST SIDE INDICATE PRESSURE AND A 
SLIGHT SHEARING FROM THE NORTHEAST. THE INITIAL POSITION IS ASSESSED 
WITH MEDIUM CONFIDENCE BASED ON THE EARLIER MICROWAVE IMAGERY 
MENTIONED PREVIOUSLY. THE INITIAL INTENSITY IS BASED ON A BLEND OF 
THE MAJORITY OF CIMSS OBJECTIVE INTENSITY AND AGENCY SUBJECTIVE 
DVORAK ESTIMATES WITH HIGH CONFIDENCE.

INITIAL WIND RADII BASIS: PERSISTENCE 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T3.5 - 55 KTS
   DEMS: T3.5 - 55 KTS
   CIMSS SATCON: 54 KTS AT 231655Z
   CIMSS ADT: 53 KTS AT 231800Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 10-20 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: THE SYSTEM IS EXPECTED TO CONTINUE TRACKING AT
A STEADY PACE NORTHWESTWARD AND GRADUALLY INTENSIFY AS IT NEARS
THE NORTHEAST COAST OF INDIA. THE INTENSIFICATION WILL BE STUNTED 
DUE TO THE SHORT DURATION OVER WATER AS WELL AS THE PRESSURE OF UPPER 
LEVEL FLOW ON THE NORTHEAST SIDE. AFTER PEAKING BETWEEN TAU 24 AND 
TAU 36, THE SYSTEM WILL MAKE LANDFALL AND QUICKLY ENCOUNTER A 
BLOCKING HIGH CENTERED OVER THE ARABIAN SEA, WHICH WILL TURN ITS 
TRACK SHARPLY TO THE SOUTHWEST. AS TC DANA CONTINUES TRACKING 
SOUTHWESTWARD OVER LAND, IT WILL DECAY QUICKLY. DISSIPATION OVER LAND 
WILL OCCUR BY TAU 72.

MODEL DISCUSSION: THE TRACK GUIDANCE IS CONSISTENT WITH A STEADY,
NORTHWESTWARD TRACK, BUT HAS A WIDER SPREAD (88 NM) OF TRACK
PLACEMENTS EVEN BY TAU 24. THE GUIDANCE ALSO AGREES WITH A LANDFALL
AROUND TAU 36, WITH SOME MODELS CLOSER TO A TAU 48 TIMEFRAME. THERE 
IS GOOD AGREEMENT CONCERNING THE SHARP TURN TO THE SOUTHWEST 
FOLLOWING LANDFALL. THE INTENSITY GUIDANCE DEPICTS A GRADUAL 
INTENSIFICATION THROUGH TAU 12 AND DECLINE IN THE INTENSITY 
THEREAFTER, WITH AT LEAST ONE RAPID INTENSITY GUIDE TRIGGERING IN THE 
NEAR-TERM. THE JTWC FORECAST IS ON THE HIGHER END OF THE INTENSITY 
CONSENSUS AND IN TIGHT AGREEMENT WITH THE MULTI-MODEL TRACK FORECAST.

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