WDPS31 PGTW 060900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 23P (FILI) WARNING NR 009// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 19.8S 163.1E INITIAL INTENSITY: 55 KTS GEOGRAPHIC REFERENCE: 217 NM NORTHWEST OF NOUMEA, NEW CALEDONIA MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 10 KTS SIGNIFICANT WAVE HEIGHT: 24 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A MEDIUM-SIZED SYSTEM THAT HAS MOSTLY MAINTAINED A NW-SE ELONGATED SHAPE DUE TO NORTHWESTERLY SHEAR. ALTHOUGH THE CENTRAL CONVECTION REMAINS DEEP. THE MSI LOOP SHOWS UNRAVELING OF THE FEEDER BANDS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A DEFINED LLC IN THE 060551Z SSMIS 91GHZ IMAGE. THE INITIAL INTENSITY IS ALSO PLACED WITH MEDIUM CONFIDENCE BASED ON AN OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES (SEE BELOW). ANALYSIS INDICATES A MARGINALLY UNFAVORABLE ENVIRONMENT WITH STRONG POLEWARD OUTFLOW AND WARM SST OFFSET BY MODERATE VWS AND DRY AIR INTRUSION IN THE LOW LEVELS. THE CYCLONE IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE STR TO THE NORTHEAST. INITIAL WIND RADII BASIS: PERSISTENCE. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T3.5 - 55 KTS KNES: T3.5 - 55 KTS PHFO: T4.0 - 65 KTS CIMSS SATCON: 61 KTS AT 060243Z CIMSS ADT: 55 KTS AT 060540Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE VWS: 15-20 KTS SST: 28-29 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM 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 FILI WILL CONTINUE ON A GENERALLY SOUTHEASTWARD TRACK UNDER THE STEERING INFLUENCE OF THE STR. THE MARGINALLY UNFAVORABLE ENVIRONMENT WILL BECOME MORE UNFAVORABLE AS VWS INCREASES AND, BY TAU 36, SST BECOMES COLDER (26C). AS A RESULT TC 23P WILL GRADUALLY ERODE, DOWN TO 40KTS BY TAU 48. CONCURRENTLY BY TAU 36, TC 23P WILL BEGIN SUBTROPICAL TRANSITION AND BY TAU 48, WILL TRANSFORM INTO A SUBTROPICAL SYSTEM. MODEL DISCUSSION: NUMERICAL MODELS ARE IN GENERAL AGREEMENT WITH A GRADUAL AND EVEN SPREAD TO 252NM BY TAU 48, LENDING MEDIUM CONFIDENCE IN THE JTWC TRACK FORECAST THAT IS LAID CLOSE TO THE MODEL CONSENSUS. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM INTENSITY 0 - 72 HR: MEDIUM// NNNN