Advisories

WDXS31 PGTW 210900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 02S (AGUEDA) WARNING NR 
003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 5.3S 52.2E
   INITIAL INTENSITY: 45 KTS
   GEOGRAPHIC REFERENCE: 775 NM EAST OF DAR ES SALAAM, TANZANIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 04 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 02S REMAINS A SHEARED SYSTEM. PERSISTENT
CONVECTION CONTINUES TO STRUGGLE TO WRAP AROUND THE PARTIALLY
EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC), AND UPPER-LEVEL
OUTFLOW REMAINS RESTRICTED TO THE EAST. A 210235Z WSF-M MWI PASS
REVEALED A WESTWARD VORTEX TILT WITH HEIGHT, WITH THE UPPER-LEVEL
CIRCULATION DISPLACED WEST OF THE LLCC. HOWEVER, ANIMATED
MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES THAT CONVECTIVE
BANDING ALONG THE SOUTHERN AND WESTERN PERIPHERY IS BEGINNING TO
IMPROVE, AND THE LLCC HAS BEGUN TO TIGHTEN. DESPITE MODERATE
MID-LEVEL VERTICAL WIND SHEAR (VWS), TC 02S IS TRAVERSING WARM SEA
SURFACE TEMPERATURES (SST) OF 27-28 DEGREES CELSIUS AND IS
SUPPORTED BY MODEST TO MODERATE WESTWARD UPPER-LEVEL DIVERGENCE.
THE OVERALL ENVIRONMENT IS MARGINALLY FAVORABLE AND MAY SUPPORT
LIMITED INTENSIFICATION OVER THE NEXT 24 HOURS. THE INITIAL
POSITION IS PLACED WITH MEDIUM CONFIDENCE ALONG THE EASTERN EDGE OF
THE CENTRAL CONVECTION. THE INITIAL INTENSITY IS SET AT 45 KTS WITH
MEDIUM CONFIDENCE BASED ON THE T3.0 DVORAK CLASSIFICATIONS FROM
PGTW AND FMEE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: WESTERN FLANK OF A LOW- TO MID-LEVEL
SUBTROPICAL RIDGE (STR)

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   DEMS: T2.5 - 35 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS SATCON: 43 KTS AT 210403Z
   CIMSS ADT: 57 KTS AT 210600Z
   CIMSS AIDT: 52 KTS AT 210530Z
   CIMSS D-MINT: 34 KTS AT 210523Z
   CIMSS D-PRINT: 39 KTS AT 210600Z

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

ANALYSIS CONFIDENCE:
   INITIAL POSITION: MEDIUM
   INITIAL INTENSITY: MEDIUM
   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 02S IS MOVING SOUTHWESTWARD ALONG THE
WESTERN PERIPHERY OF A STR TO THE EAST. OVER THE NEXT 24 HOURS, A
STR WILL BUILD TO THE SOUTH OF THE SYSTEM, TURNING TC 02S WESTWARD.
THE WESTWARD MOTION WILL CONTINUE THROUGH TAU 48. THEREAFTER, AS
THE CIRCULATION BECOMES INCREASINGLY SHALLOW, THE SYSTEM WILL TURN
SLIGHTLY EQUATORWARD AS IT MOVES WITHIN THE LOW-LEVEL SOUTHEASTERLY
FLOW. WHILE CONDITIONS MAY SUPPORT LIMITED INTENSIFICATION OVER THE
NEXT 24 HOURS, ELEVATED VWS AND THE TILTED VORTEX WILL PRECLUDE
SIGNIFICANT DEVELOPMENT. BY ABOUT TAU 24, PERSISTENT MID-LEVEL
SHEAR WILL FACILITATE DRY AIR ENTRAINMENT FROM THE WEST INTO THE
CIRCULATION. THEREFORE, THE FORECAST CONTINUES TO DEPICT A PEAK
INTENSITY OF 50 KTS FROM TAU 12 THROUGH TAU 24, FOLLOWED BY STEADY
WEAKENING. THE SYSTEM WILL DISSIPATE NEAR TAU 72.

MODEL DISCUSSION: SUBSTANTIAL SPREAD EXISTS AMONG THE TRACK
GUIDANCE, WITH DYNAMICAL MODELS PREDICTING THAT TC 02S WILL MOVE
FARTHER POLEWARD PRIOR TO TURNING WESTWARD. THE JTWC FORECAST TRACK
HAS BEEN SHIFTED SLIGHTLY NORTHWARD AND IS POSITIONED WITH MEDIUM
CONFIDENCE ON THE POLEWARD SIDE OF THE AI-MODEL MEAN, WHILE GOOGLE
DEEPMIND LIES EQUATORWARD OF THE FORECAST TRACK. THE OVERALL
INTENSITY GUIDANCE SUITE HAS TRENDED WEAKER, WITH MOST MODELS
DEPICTING NEAR-STEADY INTENSITY THROUGH TAU 24, FOLLOWED BY
WEAKENING. GIVEN RECENT SATELLITE IMAGERY INDICATING A TIGHTENING
SYSTEM, THE JTWC INTENSITY FORECAST IS SET ON THE HIGHER END OF THE
GUIDANCE ENVELOPE THROUGH TAU 24 AND CONVERGES TOWARD THE WEAKER
COAMPS-TC AND GFS SOLUTIONS THEREAFTER.

FORECAST CONFIDENCE:
   TRACK 00-72 HR: MEDIUM
   INTENSITY 00-72 HR: HIGH//
NNNN