WDXS31 PGTW 240300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (NEVILLE) WARNING NR 
041//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 22.2S 91.2E
   INITIAL INTENSITY: 50 KTS
   GEOGRAPHIC REFERENCE: 680 NM SOUTH-SOUTHWEST OF COCOS ISLANDS,
AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHWESTWARD AT 16 KTS
   SIGNIFICANT WAVE HEIGHT: 25 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) SHOWS A RAPIDLY
DECAYING SYSTEM WITH THE CENTRAL CONVECTION SHEARED SOUTHWARD OF
THE LOW LEVEL CIRCULATION (LLC), AND ITS UNRAVELING CONVECTIVE CLOUD
TOPS HAVE WARMED SIGNIFICANTLY. THE EIR LOOP ALSO SHOWS COLD AIR 
STRATOCUMULUS CLOUD LINES CONTINUE TO INTRUDE AND WRAP TOWARD THE LLC. 
THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A DEFINED 
MICROWAVE LLC IN THE 232336Z SSMIS IMAGE SUITE. THE INITIAL POSITION IS 
ALSO PLACED WITH HIGH CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY 
AND OBJECTIVE DVORAK ESTIMATES AND REFLECT THE RAPID DECAY. ANALYSIS 
INDICATES THE ENVIRONMENT HAS BECOME HIGHLY UNFAVORABLE MAINLY DUE TO 
THE COMBINED EFFECTS OF STRONG VWS, LOW LEVEL COLD AIR INTRUSION, AND 
COOLING SST.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SOUTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T3.5 - 55 KTS
   KNES: T4.0 - 65 KTS
   CIMSS ADT: 49 KTS AT 232300Z
   CIMSS AIDT: 47 KTS AT 232300Z
   CIMSS DPRINT: 45 KTS AT 232300Z
   CIMSS DMINT: 50 KTS AT 232134Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: HIGHLY UNFAVORABLE
   VWS: 25-30 KTS
   SST: 25-26 CELSIUS
   OUTFLOW: STRONG POLEWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   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 NEVILLE WILL CONTINUE TO TRACK
SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF THE STR TO THE SOUTH.
THE HIGHLY UNFAVORABLE ENVIRONMENT WILL GET WORSE AND ERODE THE
CYCLONE TO DISSIPATION BY TAU 24, LIKELY SOONER.  

MODEL DISCUSSION: NUMERICAL MODELS ARE IN TIGHT AGREEMENT UP TO TAU
24, LENDING HIGH CONFIDENCE TO THE JTWC TRACK AND INTENSITY
FORECASTS. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: HIGH
   INTENSITY 0 - 72 HR: HIGH//
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