WTXS31 PGTW 162100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 10S (JOSHUA) WARNING NR 003// RMKS/ 1. TROPICAL CYCLONE 10S (JOSHUA) WARNING NR 003 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 161800Z --- NEAR 17.5S 91.4E MOVEMENT PAST SIX HOURS - 245 DEGREES AT 07 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 - 045 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 17.5S 91.4E --- FORECASTS: 12 HRS, VALID AT: 170600Z --- 18.0S 90.0E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 245 DEG/ 08 KTS --- 24 HRS, VALID AT: 171800Z --- 18.7S 88.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 255 DEG/ 08 KTS --- 36 HRS, VALID AT: 180600Z --- 19.1S 86.7E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 270 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 181800Z --- 19.1S 85.2E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 260 DEG/ 10 KTS --- 72 HRS, VALID AT: 191800Z --- 19.6S 81.1E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 250 DEG/ 13 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 201800Z --- 21.3S 76.0E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 120 HR POSIT: 245 DEG/ 10 KTS --- 120 HRS, VALID AT: 211800Z --- 23.1S 72.0E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 162100Z POSITION NEAR 17.6S 91.0E. 16JAN21. TROPICAL CYCLONE 10S (JOSHUA), LOCATED APPROXIMATELY 1265 NM EAST-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WEST-SOUTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS A COMPLETE COLLAPSE OF DEEP CONVECTION OVER THE PREVIOUS SIX TO TWELVE HOURS, WITH REMNANT FLARING, SHALLOW CONVECTION CURRENTLY CONFINED TO THE SOUTHERN HEMISPHERE OF THE CIRCULATION. THE INITIAL POSITION IS ASSESSED WITH MODERATE CONFIDENCE BASED ON A PGTW FIX POSITION IN THE CENTER OF THE LOW-LEVEL BANDING FIELD. THE INITIAL INTENSITY IS SET AT 35 KNOTS WITH MODERATE CONFIDENCE BASED ON PGTW DVORAK CURRENT INTENSITY FIX OF T2.5, HEDGED SLIGHTLY LOWER THAN THE APRF ESTIMATE OF T3.0 (45 KTS) IN LIGHT OF THE DISTINCT LACK OF CONVECTION. TC 10S IS TRACKING WEST-SOUTHWEST ALONG THE NORTHWESTERN PERIPHERY OF THE LOW TO MID-LEVEL STR LOCATED TO THE SOUTHEAST. THE SYSTEM CONTINUES TO STRUGGLE TO MAINTAIN CORE CONVECTION, PRIMARILY DUE TO THE LACK OF STRONG OUTFLOW CHANNEL, AS IT TRANSITS THROUGH AN OTHERWISE MARGINAL ENVIRONMENT CHARACTERIZED BY LOW (5-10 KTS) VWS AND WARM (26-27 DEG C) SSTS. TC 10S IS FORECAST TO CONTINUE TRACKING GENERALLY WEST-SOUTHWEST THROUGH TAU 24, THEN MORE WESTERLY THROUGH TAU 72 IN RESPONSE TO AN ELONGATION OF THE STR TO AN EAST-WEST ORIENTATION. AFTER TAU 96, THE SYSTEM IS EXPECTED TO TURN MORE POLEWARD TOWARDS A WEAKNESS THAT DEVELOPS IN THE STR IN RESPONSE TO THE PASSAGE OF A TRANSIENT UPPER-LEVEL TROUGH. THE PASSAGE OF AN UPPER-LEVEL TROUGH TO THE SOUTH OVER THE NEXT 24-48 HOURS SHOULD ALLOW FOR IMPROVED POLEWARD OUTFLOW RESULTING IN A SHORT PERIOD OF WEAK INTENSIFICATION TO A PEAK OF 40 KNOTS BY TAU 24. THEREAFTER, THE COMBINED EFFECTS OF INCREASING VWS, COOLING SSTS AND CONVERGENT FLOW ALOFT WILL CONSPIRE TO STEADILY WEAKEN THE SYSTEM THROUGH TAU 120. NUMERICAL MODEL GUIDANCE IS IN OVERALL GOOD AGREEMENT THROUGH THE FORECAST PERIOD, WITH A 40NM SPREAD AT TAU 48, INCREASING TO 160NM AT TAU 120. THE JTWC FORECAST TRACK LIES JUST POLEWARD OF THE MULTI-MODEL CONSENSUS , CLOSELY TRACKING THE ECMWF SOLUTION WITH HIGH CONFIDENCE. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 161800Z IS 13 FEET. NEXT WARNINGS AT 170900Z AND 172100Z.// NNNN