Advisories

WDXS31 PGTW 202100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (AGUEDA) WARNING NR 
002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 5.1S 52.7E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 806 NM EAST OF DAR ES SALAAM, TANZANIA
   MOVEMENT PAST 6 HOURS: WESTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE (TC) 02S WITH FLARING, DISORGANIZED CENTRAL CONVECTION AND
RADIALLY EXPANDING CIRRUS FILAMENTS. ENVIRONMENTAL ANALYSIS
REVEALS A FAVORABLE ENVIRONMENT, CHARACTERIZED BY WARM (27-28 C)
SEA SURFACE TEMPERATURES (SST), LOW TO MODERATE (15-20 KTS)
VERTICAL WIND SHEAR (VWS), AND GOOD OUTFLOW ALOFT. THE INITIAL
POSITION IS PLACED WITH LOW CONFIDENCE BASED ON LOW-LEVEL CLOUDS
WRAPPING INTO THE DEEP CONVECTION AND THE PGTW POSITION FIX. THE
INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE
BASED ON THE AGENCY DVORAK FIXES AND CIMSS AUTOMATED INTENSITY
ESTIMATES LISTED BELOW.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: A LOW-LEVEL SUBTROPICAL RIDGE CENTERED
SOUTHEAST OF MADAGASCAR

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.5 - 35 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS ADT: 47 KTS AT 201930Z
   CIMSS AIDT: 40 KTS AT 201930Z
   CIMSS D-PRINT: 39 KTS AT 201930Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: FAVORABLE
   VWS: 15-20 KTS
   SST: 27-28 CELSIUS
   OUTFLOW: MODERATE RADIAL

ANALYSIS CONFIDENCE:
   INITIAL POSITION: LOW
   INITIAL INTENSITY: MEDIUM
   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 02S (AGUEDA) IS FORECAST TO TRACK GENERALLY
SOUTHWESTWARD THROUGH TAU 24 WHILE IT REMAINS A WEAK SYSTEM ON THE
NORTHWESTERN PERIPHERY OF THE SHALLOW STR CENTERED TO ITS
SOUTHEAST. AS 02S GAINS INTENSITY, IT WILL BE LESS SUSCEPTIBLE TO
LOWER-LEVEL STEERING AND IS EXPECTED TO TRANSITION TO DEEP-LAYER
STEERING AROUND TAU 36. SIMULTANEOUSLY, A DEEP-LAYER STR CENTERED
OVER SOUTH AFRICA IS EXPECTED TO BUILD AN EASTWARD EXTENSION. THIS
EASTWARD EXTENSION IS FORECAST TO ASSUME STEERING CONTROL OF 02S,
INDUCING A WESTWARD TRACK FROM TAU 36 THROUGH TAU 72. THE RIDGE
EXTENSION IS EXPECTED TO CONTINUE BUILDING, WHICH IS FORECAST TO
CAUSE THE SLIGHT WEST-NORTHWESTWARD LIFT AT THE END OF THE FORECAST
PERIOD. REGARDING INTENSITY, 02S IS EXPECTED TO REMAIN IN A
FAVORABLE ENVIRONMENT THROUGH TAU 36. AT THAT POINT, THE PERSISTENT
MODERATE MID-LEVEL SHEAR IS EXPECTED TO FORCE DRY AIR INTO THE
CORE, HINDERING FURTHER DEVELOPMENT AND INDUCING TERMINAL WEAKENING.
SHEAR IS EXPECTED TO PROGRESSIVELY INCREASE THROUGH THE REMAINDER
OF THE FORECAST PERIOD, ULTIMATELY RESULTING IN DISSIPATION BY TAU
96.

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN MODERATE
AGREEMENT THROUGHOUT THE FORECAST PERIOD, SUPPORTING THE JTWC TRACK
FORECAST WITH OVERALL MEDIUM CONFIDENCE. THE JTWC TRACK FORECAST
LIES EQUATORWARD ON THE PHYSICS-BASED MULTI-MODEL CONSENSUS AND
NEAR THE AI-BASED MULTI-MODEL CONSENSUS. RELIABLE INTENSITY AIDS
ARE ALSO IN MODERATE AGREEMENT, LENDING MEDIUM CONFIDENCE TO THE
JTWC INTENSITY FORECAST. THE JTWC INTENSITY FORECAST IS IN CLOSE
ALIGNMENT WITH THE MULTI-MODEL CONSENSUS AND THE HAFS-A SOLUTION.

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