WDPS31 PGTW 130300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 05P (CODY) WARNING NR 018// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 25.6S 175.8E INITIAL INTENSITY: 45 KTS GEOGRAPHIC REFERENCE: 473 NM SOUTH-SOUTHWEST OF SUVA, FIJI MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 09 KTS SIGNIFICANT WAVE HEIGHT: 22 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A BROAD, FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH ISOLATED DEEP CONVECTION SHEARED TO THE SOUTHEAST. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE MSI. A 122117Z ASCAT-B IMAGE SUPPORTS THE INITIAL POSITION AND INITIAL INTENSITY ASSESSMENT, AND WAS ALSO USED TO ADJUST THE 34-KNOT WIND RADII. TC 05P IS LOCATED UNDER STRONG WESTERLY FLOW ALOFT WITH STRONG VERTICAL WIND SHEAR AND ROBUST POLEWARD OUTFLOW. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: DEEP-LAYERED SUBTROPICAL RIDGE (STR) TO THE EAST AND NORTHEAST. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS KNES: T2.0 - 30 KTS CIMSS ADT: 35 KTS AT 122040Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY UNFAVORABLE VWS: 25-30 KTS SST: 25-26 CELSIUS OUTFLOW: STRONG POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH INITIAL WIND RADII: HIGH 3. FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: TC 05P IS NOW EXPECTED TO TRANSITION INTO A SUBTROPICAL CYCLONE. FORECAST DISCUSSION: TC 05P IS EXPECTED TO TRACK SOUTH-SOUTHEASTWARD THROUGH THE FORECAST PERIOD ALONG THE SOUTHWESTERN PERIPHERY OF THE DEEP-LAYERED STR. HOWEVER, THE SYSTEM IS EXPECTED TO SLOW SLIGHTLY AS A STRONG HIGH BUILDS TO THE SOUTH AND SLOWS ITS POLEWARD PROGRESS. THE SYSTEM WILL MAINTAIN AN INTENSITY OF 45 KNOTS THROUGH THE FORECAST PERIOD. TC CODY WILL TRACK OVER COOLER SST (24-25C) AND INTERACT WITH A STRONG BAROCLINIC ZONE ASSOCIATED WITH A SUBTROPICAL JET TO THE SOUTH. THE SYSTEM IS FORECASTED TO TRANSITION INTO A GALE- FORCE SUBTROPICAL CYCLONE BY TAU 24 WITH WEAK FRONTAL CHARACTERISTICS. AFTER TAU 36, THE SYSTEM WILL REMAIN A STRONG GALE- FORCE COLD-CORE LOW AS IT TRACKS TOWARD AND OVER NORTH ISLAND, NEW ZEALAND AND SHOULD MAINTAIN DEEP CONVECTION OVER THE SOUTHERN SEMICIRCLE WITH SUPPORT FROM AN APPROACHING MAJOR SHORTWAVE TROUGH. MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, NUMERICAL MODEL GUIDANCE REMAINS TIGHTLY CLUSTERED WITH A 35NM SPREAD IN SOLUTIONS AT TAU 36 LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK. ADDITIONALLY, ENSEMBLE GUIDANCE (EPS AND GEFS) REMAINS IN TIGHT AGREEMENT ALTHOUGH THERE IS INCREASING UNCERTAINTY IN THE TRACK NEAR NEW ZEALAND. FORECAST CONFIDENCE: TRACK 0 - 72 HR: HIGH INTENSITY 0 - 72 HR: HIGH// NNNN