WTPS31 PGTW 030300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18P (JOSIE) WARNING NR 011// RMKS/ 1. TROPICAL CYCLONE 18P (JOSIE) WARNING NR 011 02 ACTIVE TROPICAL CYCLONES IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 030000Z --- NEAR 21.7S 179.2E MOVEMENT PAST SIX HOURS - 120 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 030 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT 215 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 115 NM NORTHWEST QUADRANT REPEAT POSIT: 21.7S 179.2E --- FORECASTS: 12 HRS, VALID AT: 031200Z --- 22.7S 179.7W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 260 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 130 DEG/ 07 KTS --- 24 HRS, VALID AT: 040000Z --- 23.6S 178.5W MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 335 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 125 DEG/ 08 KTS --- 36 HRS, VALID AT: 041200Z --- 24.5S 177.0W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 435 NM SOUTHEAST QUADRANT 155 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 130 DEG/ 12 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 050000Z --- 26.0S 174.9W MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 415 NM SOUTHEAST QUADRANT 195 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT --- REMARKS: 030300Z POSITION NEAR 22.0S 179.5E. TROPICAL CYCLONE 18P (JOSIE), LOCATED APPROXIMATELY 221 NM SOUTH- SOUTHEAST OF SUVA, FIJI, HAS TRACKED EAST-SOUTHEASTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED MUTLI-SPECTRAL (MSI) SATELLITE IMAGERY SHOWS AN EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH DEEP CONVECTION SHEARED 80 NM TO THE SOUTHEAST. THE INITIAL POSITION IS BASED ON THE EXPOSED LOW LEVEL FEATURE IN THE MSI LOOP WITH HIGH CONFIDENCE. THE INITIAL INTENSITY OF 40 KNOTS IS BASED ON EXTRAPOLATION FROM A 022129Z METOP-A ASCAT PASS THAT SHOWED 40 KNOT WIND BARBS IN THE SOUTHEAST QUADRAT WHICH IS SLIGHTLY ABOVE MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM T2.0 TO T2.5 FROM KNES AND PGTW RESPECTIVELY. UPPER LEVEL ANALYSIS SHOWS THE SYSTEM HAS A POLEWARD OUTFLOW CHANNEL. ENVIRONMENTAL ANALYSIS SHOWS THAT 17P IS IN AN AREA OF HIGH (30 TO 40 KNOTS) VERTICAL WIND SHEAR AND IS TRACKING THROUGH AN AREA OF WARM (28 CELSIUS) SEA SURFACE TEMPERATURES. THE HIGH VERTICAL WIND SHEAR IS CAUSING THE CONVECTION TO DISPLACE TO THE SOUTHEAST. TC 18P WILL CONTINUE TO TRACK TO THE SOUTHEAST WHERE IT WILL ENCOUNTER COOLER SEA SURFACE TEMPERATURES AND PERSISTENT UNFAVORABLE SHEAR. THE COMBINATION OF THESE FACTORS WILL CAUSE 18P TO BEGIN TO TRANSITION INTO A SUBTROPICAL SYSTEM BY TAU 12 AND BECOME COMPLETELY SUBTROPICAL BY TAU 48. AVAILABLE DYNAMIC MODEL GUIDANCE IS IN GENERALLY GOOD AGREEMENT THAT THE SYSTEM WILL TRACK TO THE SOUTHEAST FOR THE DURATION OF THE FORECAST PERIOD. DUE TO THE GOOD AGREEMENT AMONG THE MODELS, THERE IS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030000Z IS 20 FEET. NEXT WARNINGS AT 030900Z, 031500Z, 032100Z AND 040300Z. REFER TO TROPICAL CYCLONE 17P (IRIS) WARNINGS (WTPS32 PGTW) FOR SIX-HOURLY UPDATES.//