WDIO31 PGTW 030900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02A (TWO) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 21.8N 66.8E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 180 NM SOUTH OF KARACHI, PAKISTAN
   MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A COMPACT
AND SLOWLY DEVELOPING TROPICAL CYCLONE (TC) 02A. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON PERSISTENT
CENTRAL CONVECTION OBSCURING THE LOW-LEVEL CIRCULATION CENTER
(LLCC). THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON CONSISTENT AGENCY DVORAK FIXES AND THE
WELL-ALIGNED OBJECTIVE ESTIMATES LISTED BELOW. ENVIRONMENTAL
ANALYSIS REVEALS CONDITION FAVORABLE FOR FURTHER INTENSIFICATION,
CHARACTERIZED BY WARM (28-29 C) SEA SURFACE TEMPERATURES (SST),
STRONG UPPER LEVEL DIVERGENCE ASSISTING WITH THE OUTFLOW, AS WELL
AS LOW (5-10 KTS) VERTICAL WIND SHEAR (VWS).

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: EXTENSION OF A DEEP-LAYER SUBTROPICAL
RIDGE (STR) CENTERED TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   KNES: T3.0 - 45 KTS
   CIMSS ADT: 39 KTS AT 030600Z
   CIMSS AIDT: 38 KTS AT 030500Z
   CIMSS D-PRINT: 38 KTS AT 030630Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 5-10 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: MODERATE POLEWARD AND EQUATORWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TC 02A IS CURRENTLY QUASI-STATIONARY WITH 5 KT 
OR BELOW TRANSLATION SPEEDS OVER THE LAST 12 HOURS. THE SYSTEM IS 
FORECAST TO BEGIN TURNING WEST-SOUTHWESTWARD UNDER THE INFLUENCE OF A 
STRENGTHENING RIDGING PATTERN TO THE NORTH WITHIN THE NEXT 12 HOURS. 
AS A RESULT, THE SYSTEM IS EXPECTED TO CONSOLIDATE AND INTENSIFY, 
REACHING PEAK INTENSITY OF 55-65 KTS WITHIN THE NEXT 48 HOURS. AROUND 
THAT TAU HOWEVER, A DEEP SHORTWAVE TROUGH DEVELOPING NORTH OF THE 
STEERING RIDGE WILL ERODE THE PATTERN AND SHIFT THE PRIMARY STEERING
INFLUENCE TO ANOTHER STR CENTERED TO THE SOUTHEAST OF THE SYSTEM.
THIS WILL NOT ONLY REVERSE THE TRACK MOTION TO EAST-NORTHEASTWARD,
BUT ALSO RESULT IN A WEAKENING TREND, DRIVEN BY INCREASING VERTICAL 
WIND SHEAR, BUT ALSO INCREASED DRY AIR ENTRAINMENT INTO THE CORE OF 
THE VORTEX. AS THE SYSTEM THEN TRANSITS TOWARD STATE OF GUJARAT, 
INDIA IT WILL BEGIN ITS DISSIPATION, WHICH IS EXPECTED TO BE COMPLETE 
BY OR BEFORE TAU 120, AND AFTER LANDFALL.

MODEL DISCUSSION: NUMERICAL MODEL TRACK GUIDANCE IS IN FAIR
AGREEMENT, PARTICULARLY CONSIDERING THE COMPLEXITY OF THE STEERING 
PATTERN CHANGE. JTWC OFFICIAL FORECAST IS PLACED WITH MEDIUM 
CONFIDENCE FOR THE SHORT-TERM. THE TIMELINE OF THE TRACK U-TURN 
SIGNIFICANTLY INCREASES TRACK PREDICTION UNCERTAINTY, AND THEREFORE 
THE LONG TERM FORECAST IS ASSESSED WITH LOW CONFIDENCE. INTENSITY 
GUIDANCE CONSENSUS ON THE OTHER HAND REMAINS GOOD THROUGHOUT THE 
FORECAST PERIOD, WITH MINIMAL SPREAD AMONG THE DETERMINISTIC MEMBERS. 
ALL AVAILABLE MODELS INDICATE THE BEGINNING OF WEAKENING TREND TO 
OCCUR BETWEEN TAU 36 AND 48, WHICH ALIGNS WITH THE SHIFT IN STEERING 
PATTERN.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 00-72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
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