WTXS31 PGTW 282100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 07S (CHALANE) WARNING NR 009// RMKS/ 1. TROPICAL CYCLONE 07S (CHALANE) WARNING NR 009 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 281800Z --- NEAR 20.0S 41.6E MOVEMENT PAST SIX HOURS - 275 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 010 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT REPEAT POSIT: 20.0S 41.6E --- FORECASTS: 12 HRS, VALID AT: 290600Z --- 19.7S 39.8E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 270 DEG/ 12 KTS --- 24 HRS, VALID AT: 291800Z --- 19.6S 37.2E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 265 DEG/ 10 KTS --- 36 HRS, VALID AT: 300600Z --- 19.8S 35.1E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 270 DEG/ 16 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 301800Z --- 19.8S 31.7E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 72 HR POSIT: 265 DEG/ 13 KTS --- 72 HRS, VALID AT: 311800Z --- 20.3S 26.3E MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 282100Z POSITION NEAR 19.9S 41.2E. 28DEC20. TROPICAL CYCLONE 07S (CHALANE), LOCATED APPROXIMATELY 154 NM NORTH-NORTHEAST OF EUROPA ISLAND, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS DEEP CONVECTION FLARING EAST OF THE ASSESSED LOW LEVEL CIRCULATION CENTER (LLCC), WITH THE LOW LEVEL CLOUD BANDS EXPOSED ON THE SOUTHERN SIDE. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE PARTIALLY EXPOSED CLOUD BANDING IN THE EIR LOOP. THE INITIAL INTENSITY IS HEDGED SLIGHTLY HIGHER THAN THE PGTW DVORAK INTENSITY ESTIMATE OF T2.5 (35 KTS) BASED ON AN ADT ESTIMATE OF T3.2 (49 KTS), AND A SATELLITE CONSENSUS ESTIMATE OF 45 KTS. ENVIRONMENTAL ANALYSIS REVEALS GENERALLY SUPPORTIVE CONDITIONS, WITH LOW (<10 KTS) VWS, AND VERY WARM (31- 32C) SSTS, BEING OFFSET BY WEAK OUTFLOW ALOFT. THE SYSTEM REMAINS DIRECTLY ALONG THE AXIS OF A 200 MB RIDGE EXTENDING FROM FAR NORTHERN SOUTH AFRICA TO SOUTHERN REGION OF MADAGASCAR. TC 07S CONTINUES TO TRACK WEST ALONG THE NORTHWESTERN PERIPHERY OF A LOW TO MID-LEVEL STR LOCATED TO THE SOUTHEAST OF MADAGASCAR. OVER THE NEXT 12 HOURS TC 07S IS FORECAST TO INCREASE IN INTENSITY AS THE MAIN STR WILL BUILD IN FROM THE SOUTH AND CONTINUE TO BE THE DOMINANT STEERING FACTOR AND TC 07S WILL REMAIN ON A WESTWARD TRACK THROUGH THE REMAINDER OF THE FORECAST. NUMERICAL TRACK GUIDANCE IS IN GOOD AGREEMENT THROUGH THE ENTIRETY OF THE FORECAST PERIOD, WITH A MAXIMUM SPREAD OF 90NM AT TAU 48, LENDING HIGH CONFIDENCE IN THE JTWC FORECAST TRACK. ECMWF AND COAMPS-TC SOLUTIONS CONTINUE TO SHOW A PEAK INTENSITY NEAR 55 KNOTS AS THE WEAK OUTFLOW AND MID-LEVEL DRY AIR WILL INHIBIT THE INTENSITY THROUGH TAU 12. THEREAFTER THE MID- LEVELS MOISTEN, OUTFLOW SLOWLY IMPROVES AND THE SYSTEM MOVES OVER A POOL OF HIGH OHC, ALLOWING FOR FASTER INTENSIFICATION THROUGH TAU 24. THE SYSTEM IS EXPECTED TO REACH PEAK INTENSITY OF 55 KNOTS AT TAU 36 AS IT MOVES THROUGH A FAVORABLE ENVIRONMENT. THE ONLY FACTOR LIMITING THE INTENSIFICATION REMAINS THE OUTFLOW MECHANISM ALOFT, AND ANALYSIS OF UPPER-LEVEL MODEL FIELDS LENDS SUPPORT TO A HIGHER INTENSITY THAN THE INTENSITY GUIDANCE SUGGESTS. DUE TO THE VERY WARM SST/OHC, A SLIGHT POSSIBILITY OF A HIGHER INTENSITY REMAINS NEAR TAU 36 JUST PRIOR TO LANDFALL NEAR BEIRA, MOZAMBIQUE. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 281800Z IS 14 FEET. NEXT WARNINGS AT 290900Z AND 292100Z.// NNNN