WTXS31 PGTW 250900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 07S (CHALANE) WARNING NR 002// RMKS/ 1. TROPICAL CYCLONE 07S (CHALANE) WARNING NR 002 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 250600Z --- NEAR 15.9S 55.6E MOVEMENT PAST SIX HOURS - 265 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 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 - 090 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT REPEAT POSIT: 15.9S 55.6E --- FORECASTS: 12 HRS, VALID AT: 251800Z --- 15.9S 53.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 275 DEG/ 07 KTS --- 24 HRS, VALID AT: 260600Z --- 15.8S 52.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 265 DEG/ 07 KTS --- 36 HRS, VALID AT: 261800Z --- 15.9S 51.0E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 255 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 270600Z --- 16.3S 49.5E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 250 DEG/ 07 KTS --- 72 HRS, VALID AT: 280600Z --- 17.3S 46.6E MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 96 HR POSIT: 240 DEG/ 08 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 290600Z --- 19.0S 43.7E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 120 HR POSIT: 270 DEG/ 12 KTS --- 120 HRS, VALID AT: 300600Z --- 19.0S 38.5E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT --- REMARKS: 250900Z POSITION NEAR 15.9S 55.2E. 25DEC20. TROPICAL CYCLONE 07S (CHALANE), LOCATED APPROXIMATELY 270 NM NORTH-NORTHWEST OF PORT LOUIS, MAURITIUS, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A DISORGANIZED CONVECTIVE SIGNATURE, WITH DEEP CONVECTION DISPLACED TO THE SOUTH OF THE ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC). CONVECTION HAS WEAKENED OVER THE PREVIOUS SIX HOURS, LIKELY IN RESPONSE TO THE DIURNAL CYCLE. THE INITIAL POSITION IS ASSESSED WITH MODERATE CONFIDENCE BASED ON AN ANALYSIS OF THE EXPOSED LOW-LEVEL BANDING ON THE NORTH SIDE OF THE CIRCULATION, WITH SOME LIMITED SUPPORT PROVIDED BY A 250247Z AMSU-B 89GHZ MICROWAVE IMAGE. THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS WITH FAIR CONFIDENCE BASED ON AN AVERAGE OF MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM T2.0 (PGTW) TO T3.0 (FIMP/FMEE), INFORMED BY AN ADT ESTIMATE OF T2.8 AND SATCON ESTIMATE OF 43 KNOTS. OVERALL THE ENVIRONMENT IS MARGINALLY SUPPORTIVE FOR DEVELOP, WITH LOW (5-10 KNOTS) VWS, MODERATE POLEWARD AND WESTWARD OUTFLOW AND WARM (28-29C) SSTS. UPPER-LEVEL OUTFLOW HAS DECREASED SOMEWHAT SINCE THE PREVIOUS WARNING, AS AN UPPER-LEVEL TROUGH TO THE SOUTH HAS MOVED TO THE EAST, CURTAILING THE STRONG POLEWARD OUTFLOW SEEN EARLIER. TC 07S IS MOVING WEST UNDER THE STEERING INFLUENCE OF DEEP STR LOCATED TO THE SOUTH. THE SYSTEM IS FORECAST TO CONTINUE TRACKING WEST THROUGH TAU 36, THEN TURN MORE SOUTHWESTERLY UNDER THE INFLUENCE OF THE STR LOCATED TO THE SOUTH. CHALANE IS EXPECTED TO MAKE LANDFALL ALONG THE NORTHEAST COAST OF MADAGASCAR NEAR TAU 48, THEN TRACK SOUTHWESTWARD THROUGH TAU 72, AS THE STR TO THE SOUTH REORIENTS TO A MORE SOUTHWEST TO NORTHEAST ORIENTATION. AS THE SYSTEM CROSSES THE RUGGED TERRAIN OF CENTRAL MADGASCAR AND WEAKENS, IT WILL TAKE A SHARPER SOUTH-SOUTHWEST TURN AND EMERGE BACK OVER WATER IN THE MOZAMBIQUE CHANNEL BY TAU 96. THEREAFTER, ANOTHER STR IS FORECAST TO DEVELOP SOUTH OF MADAGASCAR, PUSHING TC 07S ONTO A MORE WESTWARD TRACK THROUGH TAU 120. DUE TO THE PRESENCE OF SOMEHWAT DRIER MID-LEVEL AIR TO THE NORTH AND NORTHERLY VWS, THE SYSTEM HAS STILL FAILED TO FULLY CONSOLIDATE AND MAINTAIN A STRONG CONVECTIVE CORE. MID-LEVEL MOISTURE IS EXPECTED TO INCREASE OVER THE NEXT 24 HOURS, WHILE VWS SLACKENS, ALLOWING THE SYSTEM TO INTENSIFY TO 45 KNOTS PRIOR TO LANDFALL. AFTER REEMERGING INTO THE MOZAMBIQUE CHANNEL, WARM SSTS COMBINED WITH LOW VWS AND MORE ROBUST OUTLOW WILL ALLOW FOR REINTENSIFICATION. NUMERICAL MODEL GUIDANCE IS IN OVERALL GOOD AGREEMENT ON THE OVERALL TRACK SCENARIO, BUT DISPLAYS SIGNIFICANT ACROSS TRACK UNCERTAINTY, PARTICULARLY AFTER LANDFALL DUE TO THE COMPLEX INTERACTION WITH THE ROUGH TERRAIN AND DIFFERENT DEPICTIONS OF THE STRENGTH OF THE SYSTEM AT LANDFALL. THE JTWC FORECAST TRACK LIES SOUTH OF THE MULTI-MODEL CONSENSUS THROUGH THE DURATION OF THE FORECAST WITH OVERALL LOW CONFIDENCE IN LIGHT OF THE LARGE CROSS-TRACK UNCERTAINTY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 250600Z IS 15 FEET. NEXT WARNINGS AT 252100Z AND 260900Z.// NNNN