WDXS31 PGTW 042100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 25S (TWENTYFIVE) 
WARNING NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 11.0S 111.4E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 695 NM NORTH-NORTHWEST OF LEARMONTH,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: EAST-NORTHEASTWARD AT 12 KTS
   SIGNIFICANT WAVE HEIGHT: 15 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 25S CONTINUES TO TRACK QUICKLY EAST-
NORTHEASTWARD UNDER THE INFLUENCE OF THE NEAR-EQUATORIAL RIDGE TO
THE NORTH, WITH FLARES OF CONVECTION BECOMING HEAVILY SHEARED
WESTWARD AS DEPICTED BY ANIMATED ENHANCED INFRARED (EIR) SATELLITE
IMAGERY. THE ENVIRONMENT HAS BECOME MARGINALLY UNFAVORABLE WITH
HIGH VERTICAL WIND SHEAR (30+ KTS), SEA SURFACE TEMPERATURES
BETWEEN 29 C TO 30 C, AND MODERATE WESTWARD OUTFLOW ALOFT. THE 
INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON AN EARLIER 
041439Z METOP-C SCATTEROMETER PASS AND ANIMATED EIR.  THE INITIAL 
INTENSITY OF 35 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE 
PREVIOUSLY MENTIONED 041439Z SCATTEROMETER DATA.

INITIAL WIND RADII BASIS: 041439Z SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) POSITIONED
TO THE NORTH

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.0 - 45 KTS
   CIMSS SATCON: 42 KTS AT 041807Z
   CIMSS ADT: 33 KTS AT 041730Z
   CIMSS AIDT: 33 KTS AT 041730Z
   CIMSS D-MINT: 31 KTS AT 041807Z
   CIMSS D-PRINT: 29 KTS AT 041830Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 30+ KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

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

3. FORECAST REASONING.

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

FORECAST DISCUSSION: TROPICAL CYCLONE (TC) 25S WILL CONTINUE
GENERALLY EASTWARD UNTIL TAU 12. AFTERWARDS, TC 25S WILL MAKE A
GRADUAL PUSH SOUTHEASTWARD AS THE CIRCULATION TRACKS ALONG THE
SOUTHERN PERIPHERY OF THE NER TO THE NORTH. INTERACTION WITH THE
WIND FIELD OF A SEPARATE DEVELOPING TROPICAL DEPRESSION (93S) IS
STILL EXPECTED, CAUSING A SHARPER SOUTHEASTWARD TURN AND EVENTUALLY 
STALLING WEST OF BROWSE ISLAND. TC 25S IS FORECASTED TO MARGINALLY 
INTENSIFY OVER THE NEXT 12 HOURS. HOWEVER, TC 25S WILL CONTINUE TO BE 
INHIBITED BY A STRONG EASTERLY SHEAR IMPACTING THE VORTEX. DRY-AIR 
ENTRAINMENT FROM THE SOUTH AND WEST WILL SHALLOW OUT THE SYSTEM 
FOLLOWING TAU 12 AND INITIATE A TERMINAL WEAKENING PHASE THEREAFTER. 
25S IS EXPECTED TO DISSIPATE NEAR TAU 48, NORTHWEST OF BROOME.

MODEL DISCUSSION: CROSS-TRACK SPREAD AMONGST NUMERICAL MODEL TRACK
GUIDANCE INCREASES TO 80 NM AT TAU 24 AND 180 NM AT TAU 48,
SHOWING A GOOD CONSENSUS ON THE FORECASTED SOUTHEASTWARD TRACK. 
MODERATE UNCERTAINTY NEAR THE LATER PORTION OF THE FORECAST TRACK IS 
EXPECTED THROUGH THE TERMINAL WEAKENING PHASE. THE JTWC TRACK 
FORECAST IS PLACED CLOSE TO THE MULTI-MODEL CONSENSUS THROUGHOUT THE 
FORECAST PERIOD WITH MEDIUM CONFIDENCE. INTENSITY GUIDANCE GENERALLY 
AGREES ON MARGINAL INTENSIFICATION THROUGH TAU 12, FOLLOWED BY A 
WEAKENING TREND UNTIL THE END OF THE FORECAST PERIOD. THE JTWC 
INTENSITY FORECAST IS PLACED NEAR THE CONSENSUS WITH HIGH CONFIDENCE. 

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