WDXS31 PGTW 240900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 24S (JASMINE)
WARNING NR 002//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 17.9S 39.4E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 262 NM NORTH OF EUROPA ISLAND
   MOVEMENT PAST 6 HOURS: SOUTHWARD AT 05 KTS
   SIGNIFICANT WAVE HEIGHT: 14 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS CONVECTION
SHEARED TO THE EAST AND SOUTH OF A PARTIALLY-EXPOSED LOW-LEVEL
CIRCULATION CENTER (LLCC). THE INITIAL POSITION HAS BEEN RELOCATED
SIGNIFICANTLY TO THE WEST OF THE PREVIOUS ANALYSIS, AND IS PLACED 
WITH MEDIUM CONFIDENCE BASED ON A RECENT SATELLITE FIX FROM PGTW ON 
THE AFOREMENTIONED, PARTIALLY-EXPOSED LLCC. THE INITIAL INTENSITY OF 
40 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON A CONSENSUS OF 
SUBJECTIVE DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW, AT 35 
KNOTS, 
AND FMEE, AT 45 KNOTS, AS WELL AS A RECENT CIMSS ADT ESTIMATE OF 41 
KNOTS.

INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE EAST

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   FMEE: T3.0 - 45 KTS
   CIMSS ADT: 41 KTS AT 240615Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 20-25 KTS
   SST: 28-29 CELSIUS
   OUTFLOW: STRONG POLEWARD

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

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THE CURRENT TRACK FORECAST LIES
APPROXIMATELY 60 NM TO THE WEST OF THE PREVIOUS FORECAST TRACK
THROUGH TAU 36 DUE TO RELOCATION OF THE INITIAL POSITION. AFTER TAU
36, THE CURRENT FORECAST TRACK DEPICTS A WIDER EQUATORWARD TURN
THAN PREVIOUSLY ANTICIPATED. HOWEVER, THE OVERALL FORECAST
PHILOSOPHY HAS NOT CHANGED FROM THE PREVIOUS FORECAST.

FORECAST DISCUSSION: TC 24S WILL TRACK POLEWARD THROUGH THE NEXT 36
HOURS UNDER THE CONTINUED STEERING INFLUENCE OF THE STR TO THE
EAST. STRONG EASTERLY VERTICAL WIND SHEAR WILL CONTINUE TO IMPACT
THE SYSTEM THROUGHOUT THE FORECAST PERIOD AND EVENTUALLY RESULT IN
DISSIPATION, MOST LIKELY BY TAU 48, DESPITE SUPPORTIVE SEA SURFACE
TEMPERATURES AND UPPER-LEVEL OUTFLOW. THE SYSTEM IS EXPECTED TO
TAKE AN EQUATORWARD TURN AS THE PRIMARY STEERING INFLUENCE
TRANSFERS TO A BUILDING LOW-LEVEL RIDGE TO THE WEST AFTER TAU 36.

MODEL DISCUSSION: NUMERICAL MODELS, WITH THE EXCEPTION OF GFS, ARE
GENERALLY IN AGREEMENT REGARDING A POLEWARD TRACK, WEAKENING AND AN
EQUATORWARD TURN IN THE CENTRAL MOZAMBIQUE CHANNEL. GFS DEPICTS A
TRACK FARTHER POLEWARD AND ACROSS SOUTHERN MADAGASCAR, WHICH IS
CONSISTENT WITH A SUBSET OF GEFS ENSEMBLE MEMBERS. THE MAJORITY OF
GEFS AND OTHER ENSEMBLE (INCLUDING EC-EPS AND MOGREPS-G) MEMBERS
DEPICT A POLEWARD TRACK FOLLOWED BY AN EQUATORWARD TURN WITHIN THE
MOZAMBIQUE CHANNEL. ALTHOUGH A LARGE MAJORITY OF DETERMINISTIC AND
ENSEMBLE MODEL SOLUTIONS SUPPORT THE CURRENT TRACK FORECAST 
PHILOSOPHY, THEY VARY SIGNIFICANTLY IN THEIR DEPICTION OF THE TIMING 
AND TIGHTNESS OF THE EQUATORWARD TURN. THE CURRENT FORECAST LIES NEAR
THE MIDDLE OF THE MULTI-MODEL ENVELOPE AND DEPICTS A SLIGHTLY
TIGHTER TURN THAN THE CONSENSUS, TO OFFSET THE GFS OUTLIER
SOLUTION. GIVEN NOTED MODEL SPREAD, CONFIDENCE IN THE TRACK
FORECAST IS LOW. THE INTENSITY FORECAST IS A BIT MORE
STRAIGHTFORWARD, WITH BETTER MODEL AGREEMENT AND A SOLID
EXPECTATION THAT CONTINUED VERTICAL WIND SHEAR WILL PRECLUDE
SIGNIFICANT INTENSIFICATION.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM//
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