WDIO31 PGTW 230900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 03B (DANA)       
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 16.6N 89.3E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 364 NM SOUTH OF KOLKATA, INDIA
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 10 KTS
   SIGNIFICANT WAVE HEIGHT: 18 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A RAPIDLY
CONSOLIDATING SYSTEM WITH AN EXPANDING CENTRAL DENSE OVERCAST 
OBSCURING THE LOW-LEVEL CIRCULATION CENTER (LLCC). A 230404Z MHS
89GHZ MICROWAVE IMAGE INDICATES THE CENTER IS LOCATED ALONG THE
NORTHERN EDGE OF THE CORE CONVECTION, WITH CONVECTIVE BANDING
CONFINED PRIMARILY TO THE WESTERN SEMICIRCLE. ANIMATED METEOSAT-9
WATER VAPOR RGB IMAGERY INDICATES ROBUST EQUATORWARD AND POLEWARD
OUTFLOW, ENHANCED BY THE STRONG WESTERLIES TO THE NORTH. DESPITE
EASTERLY VERTICAL WIND SHEAR, THE SYSTEM IS FIGHTING THE VWS, WITH
EXPANDING EASTWARD OUTFLOW. A 230320Z ASCAT-C IMAGE REVEALED A
WELL-DEFINED CENTER WITH 35 KNOT WINDS OVER THE SOUTHERN SEMICIRCLE, 
WHICH SUPPORTS THE DECISION TO UPGRADE THE SYSTEM TO TROPICAL STORM 
STRENGTH. AGENCY DVORAK ESTIMATES RANGE FROM 35 TO 45 KNOTS.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

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

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   KNES: T3.0 - 45 KTS
   DEMS: T2.5 - 35 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY FAVORABLE
   VWS: 20-25 KTS
   SST: 30-31 CELSIUS
   OUTFLOW: STRONG POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 03B WILL TRACK POLEWARD
THROUGH TAU 72 ALONG THE WESTERN PERIPHERY OF THE STR. ROBUST
POLEWARD OUTFLOW WILL AID IN THE STEADY STRENGTHENING OF THE SYSTEM
TO A PEAK INTENSITY OF 55 KNOTS BY TAU 24. THE SYSTEM WILL BE ABLE
TO SUSTAIN 55 KNOTS THROUGH TAU 36 AS IT TRACKS INTO A LARGE BAY,
WITH THE CONCAVE SHAPE OF THE COAST ENHANCING LOW-LEVEL CONVERGENT
FLOW. HIGHER PEAK INTENSITY IS POSSIBLE IN THIS COASTAL REGION.
AFTER TAU 72, THE SYSTEM WILL MAKE LANDFALL AND BEGINNING TO WEAKEN
QUICKLY AS IT TURNS SHARPLY WESTWARD TO WEST-SOUTHWESTWARD UNDER A
BUILDING STR TO THE NORTH AND NORTHWEST. THE SYSTEM WILL DISSIPATE
BY TAU 96 AS IT TRACKS INLAND.      

MODEL DISCUSSION: DETERMINISTIC GUIDANCE IS IN GOOD AGREEMENT THROUGH 
TAU 48, DIVERGING DURING THE SHARP WESTWARD TURN AND OVERLAND TRACK. 
EPS AND GEFS PROBABILISTIC GUIDANCE INDICATE A SIMILAR SPREAD OF 
SOLUTIONS. RELIABLE INTENSITY GUIDANCE IS IN GOOD AGREEMENT; HOWEVER, 
THE JTWC PEAK INTENSITY IS HEDGED HIGHER THAN THE INTENSITY CONSENSUS 
(ICNW) DUE TO THE ROBUST OUTFLOW. PROBABILISTIC GUIDANCE ALSO 
INDICATES A 40 TO 60 PERCENT PROBABILITY FOR MODERATE INTENSIFICATION 
(LESS THAN 30 KNOTS) THROUGH TAU 24.   

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