SUBJ: TROPICAL CYCLONE 21S (GEZANI) WARNING NR 021 WTXS32 PGTW 172100 1. TROPICAL CYCLONE 21S (GEZANI) WARNING NR 021 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 171800Z --- NEAR 31.5S 42.1E MOVEMENT PAST SIX HOURS - 195 DEGREES AT 14 KTS POSITION ACCURATE TO WITHIN 030 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT REPEAT POSIT: 31.5S 42.1E --- FORECASTS: 12 HRS, VALID AT: 180600Z --- 34.2S 41.7E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 170 DEG/ 14 KTS --- 24 HRS, VALID AT: 181800Z --- 36.9S 42.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT --- REMARKS: 172100Z POSITION NEAR 32.2S 42.0E. 17FEB26. TROPICAL CYCLONE 21S (GEZANI), LOCATED APPROXIMATELY 567 NM SOUTH OF EUROPA ISLAND, HAS TRACKED SOUTH-SOUTHWESTWARD AT 14 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL CYCLONE 21S WITH A SHALLOW, FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC). A 171551Z RCM-1 SAR IMAGE REVEALED MAXIMUM WINDS OF AROUND 55-60 KTS WITHIN THE EASTERN SEMCIRCLE. THE INITIAL INTENSITY OF 50 KTS IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE SLIGHT HIGH BIAS OF THE RCM-1 SENSOR. ENVIRONMENTAL CONDITIONS ARE ANALYZED TO BE UNFAVORABLE BASED ON STRONG POLEWARD OUTFLOW GREATLY OFFSET BY HIGH (25-30 KTS) VERTICAL WIND SHEAR, SIGNIFICANT DRY AIR ENTRAINMENT, AND COOL (24-25 C) SEA SURFACE TEMPERATURES. 21S IS FORECAST TO TRACK SOUTHWARD OVER THE NEXT 24 HOURS WITH STEADY WEAKENING AS IT CONTINUES TO FEEL THE EFFECTS OF THE HOSTILE ENVIRONMENT. SUBTROPICAL TRANSITION IS FORECAST TO COMPLETE WITHIN 12 HOURS AS THE VORTEX CONTINUES TO SHALLOW OUT AND INTERACTS WITH SEA SURFACE TEMPERATURES OF AROUND 22-23 C. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION. MINIMUM CENTRAL PRESSURE AT 171800Z IS 991 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 171800Z IS 24 FEET.// BT #0001 NNNN