WTXS31 PGTW 010900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 27S (COURTNEY) WARNING NR 020// RMKS/ 1. TROPICAL CYCLONE 27S (COURTNEY) WARNING NR 020 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 010600Z --- NEAR 25.0S 88.4E MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 KTS POSITION ACCURATE TO WITHIN 030 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING SUBTROPICAL RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT REPEAT POSIT: 25.0S 88.4E --- FORECASTS: 12 HRS, VALID AT: 011800Z --- 25.2S 87.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY SUBTROPICAL RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT --- REMARKS: 010900Z POSITION NEAR 25.1S 88.3E. 01APR25. TROPICAL CYCLONE 27S (COURTNEY), LOCATED APPROXIMATELY 907 NM SOUTH-SOUTHWEST OF THE COCOS ISLANDS, HAS TRACKED WEST- SOUTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTI-SPECTRAL SATELLITE IMAGERY DEPICTS A COMPLETELY EXPOSED, ELONGATED, LOW-LEVEL CIRCULATION CENTER (LLCC) WITH CONVECTION HEAVILY SHEARED OFF TO THE SOUTHEAST. A 010232Z METOP-B ASCAT IMAGE REVEALED THE ASYMMETRIC WIND FIELD WITH 40-45 KTS CONFINED TO THE SOUTHERN SEMICIRCLE. ENVIRONMENTAL ANALYSIS INDICATES THAT TC 27S IS PLACED WITHIN A HIGHLY UNFAVORABLE ENVIRONMENT CHARACTERIZED BY VERY HIGH (OVER 50 KTS) NORTHWESTERLY VERTICAL WIND SHEAR, SIGNIFICANT DRY AIR ENTRAINMENT, AND COOL (24-25 C) SEA SURFACE TEMPERATURES. TC 27S IS EXPECTED TO TRACK FURTHER WESTWARD OVER THE NEXT COUPLE DAYS, ALONG THE NORTHERN PERIPHERY OF A SHALLOW SUBTROPICAL RIDGE POSITIONED TO THE SOUTH OF THE SYSTEM. INTENSITY IS FORECAST TO CONTINUE DROPPING IN RESPONSE TO THE INCREASINGLY HOSTILE ENVIRONMENT. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT REGARDING BOTH THE WESTWARD TRACK AND THE CONTINUED WEAKENING TREND. SUBTROPICAL TRANSITION IS FORECAST TO COMPLETE WITHIN THE NEXT 12 HOURS AS THE VORTEX FURTHER SHALLOWS AND BECOMES COMPLETELY TAKEN OVER BY DRY AIR. 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 010600Z IS 993 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 010600Z IS 20 FEET.// NNNN