WTXS31 PGTW 270300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 13S (THIRTEEN) WARNING NR 013// RMKS/ 1. TROPICAL CYCLONE 13S (THIRTEEN) WARNING NR 013 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 270000Z --- NEAR 19.5S 91.8E MOVEMENT PAST SIX HOURS - 270 DEGREES AT 13 KTS POSITION ACCURATE TO WITHIN 040 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT REPEAT POSIT: 19.5S 91.8E --- FORECASTS: 12 HRS, VALID AT: 271200Z --- 19.3S 89.8E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 280 DEG/ 13 KTS --- 24 HRS, VALID AT: 280000Z --- 18.9S 87.1E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 280 DEG/ 15 KTS --- 36 HRS, VALID AT: 281200Z --- 18.3S 83.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 280 DEG/ 19 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 290000Z --- 17.7S 80.0E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 280 DEG/ 16 KTS --- 72 HRS, VALID AT: 300000Z --- 16.3S 73.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 280 DEG/ 15 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 310000Z --- 15.1S 67.3E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 275 DEG/ 13 KTS --- 120 HRS, VALID AT: 010000Z --- 14.5S 62.0E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT --- REMARKS: 270300Z POSITION NEAR 19.4S 91.3E. 27JAN21. TROPICAL CYCLONE 13S (THIRTEEN), LOCATED APPROXIMATELY 1342 NM SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WESTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS THAT THEY SYSTEM IS BEING INFLUENCED BY SUBSTANTIAL VERTICAL WIND SHEAR (VWS), WITH FLARING CONVECTION DISPLACED WELL TO THE SOUTHEAST OF THE EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC). THE EXPOSED LLCC IN CONJUNCTION WITH A 262225Z SSMIS 91GHZ MICROWAVE IMAGE REVEALS SHALLOW BANDING OVER THE WESTERN AND NORTHERN HEMISPHERE WRAPPING INTO A WELL DEFINED LLCC, PROVIDING HIGH CONFIDENCE TO THE INITIAL POSITION. THE INITIAL INTENSITY IS HEDGED ABOVE PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.0 (30 KTS) BASED ON A 262340Z ADT ESTIMATE OF T2.7 (39 KTS) AND A SATCON ESTIMATE OF 36 KNOTS. ENVIRONMENTAL ANALYSIS REVEALS MARGINALLY SUPPORTIVE CONDITIONS CHARACTERIZED BY MODERATE (10-15 KTS) NORTHERLY VWS, GOOD POLEWARD OUTFLOW, MARGINAL SSTS (26C) AND ENTRAINMENT OF DRIER AIR, PARTICULARLY ON THE WEST AND NORTHERN PORTIONS OF THE CIRCULATION. TC 13S IS FORECAST TO TRACK WEST- NORTHWEST ALONG THE NORTHERN PERIPHERY OF A LOW TO MID-LEVEL STR ENTRENCHED TO THE SOUTH. THE SYSTEM WILL STRUGGLE AGAINST THE MARGINAL CONDITIONS THROUGH TAU 48, MAINTAINING AN AVERAGE INTENSITY OF 35 KNOTS WITH SLIGHTLY LOWER AND HIGHER EXCURSIONS ON A DIURNAL CYCLE. IF IT SURVIVES PASSAGE THROUGH THIS MARGINAL ENVIRONMENT, AND AS IT MOVES INTO AN IMPROVED ENVIRONMENT AFTER TAU 72, IT IS EXPECTED TO SLOWLY INTENSIFY TO A PEAK OF 50 KNOTS BY TAU 120. NUMERICAL MODEL GUIDANCE IS IN VERY GOOD AGREEMENT THROUGH THE DURATION OF THE FORECAST, LENDING HIGH CONFIDENCE TO THE TO THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 270000Z IS 13 FEET. NEXT WARNINGS AT 271500Z AND 280300Z.// NNNN