Tropical
Cyclones
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Tropical Cyclone MITCHELL Southern Hemisphere Summary |
WTXS21 PGTW 20121228 09:30z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE FORMATION ALERT// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 110 NM EITHER SIDE OF A LINE FROM 15.1S 111.8E TO 20.5S 109.8E WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO BE 25 TO 30 KNOTS. METSAT IMAGERY AT 280630Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 15.3S 111.7E. THE SYSTEM IS MOVING SOUTHWESTWARD AT 05 KNOTS. 2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 14.8S 112.2E IS NOW LOCATED NEAR 15.3S 111.7E, APPROXIMATELY 435 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS A SIGNIFICANT INCREASE IN DEEP CONVECTION OVER THE PAST 12 HOURS, WITH FORMATIVE BANDING DEVELOPING AROUND THE PERIPHERY OF THE SYSTEM EVIDENT IN A 280510Z TRMM MICROWAVE IMAGE. THIS DISTURBANCE LIES JUST TO THE WEST OF AN UPPER LEVEL ANTICYCLONE CENTER, DIRECTLY BENEATH A SUBTROPICAL RIDGE AXIS IN AN AREA OF LIGHT (10 TO 15 KNOT) VERTICAL WIND SHEAR AND FAVORABLE DUAL CHANNEL OUTFLOW. A 280201Z PARTIAL ASCAT PASS SHOWS 25 KNOT NORTHERLY WINDS ALONG THE EASTERN PERIPHERY OF THE DISTURBANCE, WITH A FEW 30 KNOT EAST-NORTHEASTERLY WINDS IN THE SOUTHEAST QUADRANT. NUMERICAL MODEL GUIDANCE DEVELOPS THIS SYSTEM OVER THE NEXT 24 TO 36 HOURS AS IT CONTINUES TO MOVE TO THE SOUTH-SOUTHWEST. MAXIMUM SUSTAINED SURFACE WINDS ARE ESTIMATED AT 25 TO 30 KNOTS. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1004 MB. DUE TO INCREASING CONSOLIDATION OF THE LLCC AND A FAVORABLE UPPER LEVEL ENVIRONMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24 HOURS IS HIGH. 3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY 290930Z.// ========================================================================= WTXS31 PGTW 20121228 21:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06S (SIX) WARNING NR 001// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/280921ZDEC2012// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. TROPICAL CYCLONE 06S (SIX) WARNING NR 001 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 16.3S 110.7E MOVEMENT PAST SIX HOURS - 205 DEGREES AT 07 KTS POSITION ACCURATE TO WITHIN 030 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 REPEAT POSIT: 16.3S 110.7E --- FORECASTS: 12 HRS, VALID AT: 290600Z --- 17.6S 110.3E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 195 DEG/ 09 KTS --- 24 HRS, VALID AT: 291800Z --- 19.3S 109.9E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 190 DEG/ 09 KTS --- 36 HRS, VALID AT: 300600Z --- 21.0S 109.5E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 195 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 301800Z --- 22.8S 109.0E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 200 DEG/ 08 KTS --- 72 HRS, VALID AT: 311800Z --- 25.6S 107.8E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 282100Z POSITION NEAR 16.6S 110.6E. TROPICAL CYCLONE (TC) 06S, LOCATED APPROXIMATELY 400 NM NORTH- NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTH-SOUTHWESTWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH TIGHTLY-CURVED DEEP CONVECTIVE BANDING WRAPPING INTO THE SYSTEM. A 281433Z ASCAT IMAGE SHOWED A WELL-DEFINED CIRCULATION WITH 30 TO 35 KNOT WINDS OVER THE SOUTHERN SEMI-CIRCLE. BECAUSE OF THE IMPROVED ORGANIZATION AND DVORAK INTENSITY ESTIMATES OF 35 KNOTS, THE INITIAL INTENSITY IS ASSESSED AT 35 KNOTS. ADDITIONALLY, THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION AND RECENT TRACK MOTION. TC 06S IS LOCATED WITHIN A FAVORABLE ENVIRONMENT WITH GOOD POLEWARD OUTFLOW ENHANCED BY AN UPPER-LOW OVER SOUTHWEST AUSTRALIA. TC 06S IS FORECAST TO CONTINUE TRACKING SOUTH-SOUTHWESTWARD THROUGH TAU 72 ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST, WHICH IS POSITIONED CLOSE TO THE MULTI- MODEL CONSENSUS. TC 06S IS FORECAST TO INTENSIFY THROUGH TAU 24 DUE TO CONTINUED FAVORABLE CONDITIONS. HOWEVER, THE SYSTEM IS EXPECTED TO WEAKEN RAPIDLY AS IT TRACKS SOUTH OF 20S DUE TO COOLER SST (24 TO 26C). TC 06S IS EXPECTED TO DISSIPATE BY TAU 72. THIS WARNING SUPERSEDES AND CANCELS REF A, JOINT TYPHOON WRNCEN PEARL HARBOR HI 280930Z DEC 12 TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 280930). MAXIMUM SIGNIFICANT WAVE HEIGHT AT 281800Z IS 10 FEET. NEXT WARNINGS AT 290300Z, 290900Z, 291500Z AND 292100Z.// ========================================================================= WTXS31 PGTW 20121229 03:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 002// RMKS/ 1. TROPICAL CYCLONE 06S (MITCHELL) 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: 290000Z --- NEAR 17.0S 110.6E MOVEMENT PAST SIX HOURS - 190 DEGREES AT 07 KTS POSITION ACCURATE TO WITHIN 030 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 - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT REPEAT POSIT: 17.0S 110.6E --- FORECASTS: 12 HRS, VALID AT: 291200Z --- 18.7S 110.2E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 190 DEG/ 11 KTS --- 24 HRS, VALID AT: 300000Z --- 20.8S 109.8E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 195 DEG/ 10 KTS --- 36 HRS, VALID AT: 301200Z --- 22.8S 109.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 200 DEG/ 11 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 310000Z --- 24.8S 108.4E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 290300Z POSITION NEAR 17.4S 110.5E. TROPICAL CYCLONE (TC) 06S, LOCATED APPROXIMATELY 365 NM NORTH- NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 07 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE IMAGERY DEPICTS A CONSOLIDATING LOW-LEVEL CIRCULATION CENTER (LLCC) WITH TIGHTLY-CURVED DEEP CONVECTIVE BANDING WRAPPING INTO THE SYSTEM. A 282234Z SSMIS IMAGE INDICATES THAT THE DEEP CONVECTIVE BANDING IS LOCATED PRIMARILY OVER THE SOUTHERN AND WESTERN SEMI-CIRCLES WITH SHALLOW BANDING ELSEWHERE. THE INITIAL INTENSITY IS ASSESSED AT 40 KNOTS, WHICH IS SLIGHTLY LOWER THAN THE DVORAK ESTIMATES OF 45 KNOTS, BASED ON THE RECENT WEAKENING OF CORE CONVECTION EVIDENCED BY WARMING CLOUD TOP TEMPERATURES OVER THE PAST FEW HOURS. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION AND RECENT TRACK MOTION. TC 06S IS LOCATED WITHIN A FAVORABLE ENVIRONMENT WITH GOOD POLEWARD OUTFLOW ENHANCED BY AN UPPER-LOW OVER SOUTHWEST AUSTRALIA. TC 06S IS FORECAST TO CONTINUE TRACKING SOUTH-SOUTHWESTWARD THROUGH TAU 48 ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST, WHICH IS POSITIONED CLOSE TO THE MULTI- MODEL CONSENSUS. TC 06S IS FORECAST TO INTENSIFY THROUGH TAU 12 DUE TO CONTINUED FAVORABLE CONDITIONS. HOWEVER, THE SYSTEM IS EXPECTED TO WEAKEN RAPIDLY AS IT TRACKS SOUTH OF 20S DUE TO COOLER SST (24 TO 26C). TC 06S IS EXPECTED TO DISSIPATE BY TAU 48. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 290000Z IS 12 FEET. NEXT WARNINGS AT 290900Z, 291500Z, 292100Z AND 300300Z.// ========================================================================= WTXS31 PGTW 20121229 09:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 003// RMKS/ 1. TROPICAL CYCLONE 06S (MITCHELL) 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: 290600Z --- NEAR 17.9S 110.3E MOVEMENT PAST SIX HOURS - 200 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 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 RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 17.9S 110.3E --- FORECASTS: 12 HRS, VALID AT: 291800Z --- 19.6S 109.8E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 200 DEG/ 11 KTS --- 24 HRS, VALID AT: 300600Z --- 21.6S 109.1E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 200 DEG/ 11 KTS --- 36 HRS, VALID AT: 301800Z --- 23.6S 108.3E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 200 DEG/ 10 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 310600Z --- 25.5S 107.5E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 290900Z POSITION NEAR 18.3S 110.2E. TROPICAL CYCLONE (TC) 06S (MITCHELL), LOCATED APPROXIMATELY 330 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTH-SOUTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TIGHTLY-CURVED DEEP CONVECTIVE BANDING WRAPPING INTO A WELL DEFINED LOW-LEVEL CIRCULATION CENTER (LLCC). THE INTIAL POSITION IS BASED ON THIS WELL DEFINED LLCC READILY APPARENT IN THE MSI WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS BASED ON CONGRUENT DVORAK CURRENT INTENSITY ESTIMATES FROM PGTW, KNES AND APRF. UPPER-LEVEL ANALYSIS REVEALS TC 06S IS LOCATED UNDERNEATH THE SUBTROPICAL RIDGE (STR) AXIS WITH GOOD POLEWARD OUTFLOW WHICH IS BEING ENHANCED BY AN UPPER- LOW OVER SOUTHWEST AUSTRALIA. TC 06S IS FORECAST TO CONTINUE TRACKING SOUTH-SOUTHWESTWARD THROUGH TAU 48 ALONG THE WESTERN PERIPHERY OF A STR THAT IS MERIDIONALLY ORIENTED ALONG THE WESTERN COAST OF AUSTRALIA. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT, THEREFORE, THERE IS HIGH CONFIDENCE IN THE JTWC TRACK FORECAST, WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS. TC 06S IS FORECAST TO INTENSIFY THROUGH TAU 12 DUE TO CONTINUED FAVORABLE CONDITIONS. HOWEVER, THE SYSTEM IS EXPECTED TO WEAKEN RAPIDLY AS IT TRACKS SOUTH OF 20S DUE TO COOLER SST (24 TO 26 DEGREES CELSIUS). TC 06S IS EXPECTED TO DISSIPATE BY TAU 48. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 290600Z IS 15 FEET. NEXT WARNINGS AT 291500Z, 292100Z, 300300Z AND 300900Z.// ========================================================================= WTXS31 PGTW 20121229 15:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 004// RMKS/ 1. TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 004 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 291200Z --- NEAR 18.9S 110.2E MOVEMENT PAST SIX HOURS - 185 DEGREES AT 10 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 - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 18.9S 110.2E --- FORECASTS: 12 HRS, VALID AT: 300000Z --- 20.9S 109.7E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 195 DEG/ 10 KTS --- 24 HRS, VALID AT: 301200Z --- 22.9S 109.1E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY VECTOR TO 36 HR POSIT: 200 DEG/ 10 KTS --- 36 HRS, VALID AT: 310000Z --- 24.8S 108.3E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 48 HR POSIT: 190 DEG/ 10 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 311200Z --- 26.8S 108.0E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 291500Z POSITION NEAR 19.4S 110.1E. TROPICAL CYCLONE (TC) 06S (MITCHELL), LOCATED APPROXIMATELY 290 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY (IR) DEPICTS THE LOW-LEVEL CIRCULATION CENTER HAS BECOME ELONGATED AND CONVECTION HAS WEAKENED WITH A SMALL COLD DENSE OVERCAST FEATURE BEGINNING TO FORM. THE INITIAL POSITION IS BASED ON THE IR LOOP AND SATELLITE FIXES FROM MULTIPLE REPORTING AGENCIES. THE INITIAL INTENSITY IS ASSESSED AT 40 KNOTS BASED ON THE WEAKENING TREND OBSERVED IN THE IR AND DECREASING DVORAK INTENSITY ESTIMATES FROM ALL AGENCIES. UPPER-LEVEL ANALYSIS REVEALS TC 06S HAS MAINTAINED POLEWARD OUTFLOW INTO THE SUBTROPICAL JET LOCATED OVER CENTRAL AUSTRALIA BUT THE UPPER-LEVEL LOW WHICH WAS ENHANCING THIS OUTFLOW HAS FILLED. TC 06S IS FORECAST TO CONTINUE TRACKING SOUTH-SOUTHWESTWARD THROUGH THE FORECAST PERIOD ALONG THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE THAT IS MERIDIONALLY ORIENTED ALONG THE WESTERN COAST OF AUSTRALIA. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT LENDING TO HIGH CONFIDENCE IN THE JTWC TRACK FORECAST, WHICH IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS. TC 06S IS FORECAST TO MAINTAIN INTENSITY FOR THE NEXT 12 HOURS AND THEN SLOWLY WEAKEN AS COOLER SEA SURFACE TEMPERATURES (24 TO 26 DEGREES CELSIUS) ARE ENCOUNTERED SOUTH OF 20S. TC 06S IS EXPECTED TO DISSIPATE BY TAU 48 DUE TO THE DECREASING ENVIRONMENTAL CONDITIONS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 291200Z IS 17 FEET. NEXT WARNINGS AT 300300Z AND 301500Z.// ========================================================================= WTXS31 PGTW 20121229 21:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 005// RMKS/ 1. TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 005 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 291800Z --- NEAR 20.0S 110.3E MOVEMENT PAST SIX HOURS - 180 DEGREES AT 10 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 - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT REPEAT POSIT: 20.0S 110.3E --- FORECASTS: 12 HRS, VALID AT: 300600Z --- 21.9S 109.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 200 DEG/ 11 KTS --- 24 HRS, VALID AT: 301800Z --- 23.9S 109.1E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 36 HR POSIT: 195 DEG/ 10 KTS --- 36 HRS, VALID AT: 310600Z --- 25.8S 108.5E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 292100Z POSITION NEAR 20.5S 110.2E. TROPICAL CYCLONE (TC) 06S (MITCHELL), LOCATED APPROXIMATELY 240 NM WEST-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES THAT TC 06S IS WEAKENING RAPIDLY WITH DIMINISHING DEEP CONVECTION. HOWEVER, A 291833Z AMSU IMAGE INDICATES DEEP CONVECTIVE BANDING OVER THE SOUTHERN CIRCLE WITH TIGHTLY-WRAPPED SHALLOW BANDING ELSEWHERE. A 291552Z OCEANSAT IMAGE SHOWS 30 TO 35 KNOT WINDS AND A SYMMETRIC CIRCULATION. THE INITIAL INTENSITY IS ASSESSED SLIGHTLY HIGHER THAN THE SCATTEROMETER DATA BASED ON AN AVERAGE OF DVORAK CURRENT INTENSITY ESTIMATES RANGING FROM 35 TO 45 KNOTS. THERE IS FAIR CONFIDENCE IN THE INITIAL POSITION BASED ON THE AMSU IMAGE. TC 06S IS TRACKING SOUTHWARD TO SOUTH-SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE, WHICH IS ENTRENCHED OVER WESTERN AUSTRALIA AS EVIDENCED BY THE LATEST PORT HEDLAND SOUNDING SHOWING 25 TO 35 KNOT NORTH-NORTHEASTERLY STEERING FLOW. THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST BASED ON A 65-NM SPREAD IN DYNAMIC MODEL GUIDANCE AT TAU 36. TC 06S IS FORECAST TO WEAKEN THROUGHOUT THE FORECAST PERIOD AND SHOULD DISSIPATE OVER COOL SST (LESS THAN 25C) BY TAU 36. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 291800Z IS 18 FEET. NEXT WARNINGS AT 300300Z, 300900Z, 301500Z AND 302100Z.// ========================================================================= WTXS31 PGTW 20121230 03:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 006// RMKS/ 1. TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 300000Z --- NEAR 21.3S 110.1E MOVEMENT PAST SIX HOURS - 185 DEGREES AT 13 KTS POSITION ACCURATE TO WITHIN 040 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 - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT REPEAT POSIT: 21.3S 110.1E --- FORECASTS: 12 HRS, VALID AT: 301200Z --- 23.8S 109.2E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 195 DEG/ 12 KTS --- 24 HRS, VALID AT: 310000Z --- 26.2S 108.6E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 300300Z POSITION NEAR 21.9S 109.9E. TROPICAL CYCLONE (TC) 06S (MITCHELL), LOCATED APPROXIMATELY 225 NM WEST-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY INDICATES THAT TC 06S IS WEAKENING RAPIDLY WITH DIMINISHING DEEP CONVECTION. HOWEVER, A 292222Z SSMIS IMAGE INDICATES DEEP CONVECTIVE BANDING REMAINS OVER THE SOUTHERN SEMI-CIRCLE WITH A WELL-DEFINED CENTER. A 291552Z OCEANSAT IMAGE SHOWS 30 TO 35 KNOT WINDS AND A SYMMETRIC CIRCULATION. THE INITIAL INTENSITY IS ASSESSED SLIGHTLY HIGHER THAN THE DVORAK CURRENT INTENSITY ESTIMATES OF 35 KNOTS BASED ON THE LOW-LEVEL STRUCTURE, A RECENT SATCON ESTIMATE OF 45 KNOTS AND THE SSMIS WIND PRODUCT, WHICH SHOWED 35 TO 40 KNOT CORE WINDS. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION BASED ON THE SSMIS IMAGE. TC 06S IS TRACKING SOUTHWARD TO SOUTH-SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE, WHICH IS ENTRENCHED OVER WESTERN AUSTRALIA AS EVIDENCED BY THE LATEST PORT HEDLAND SOUNDING SHOWING 25 TO 35 KNOT NORTH-NORTHEASTERLY STEERING FLOW. THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST BASED ON A 85-NM SPREAD IN DYNAMIC MODEL GUIDANCE AT TAU 24. TC 06S IS FORECAST TO WEAKEN THROUGHOUT THE FORECAST PERIOD AND SHOULD DISSIPATE BY TAU 24 AS IT TRACKS OVER COOL SST (LESS THAN 24C) AND ENCOUNTERS INCREASING VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 300000Z IS 18 FEET. NEXT WARNINGS AT 300900Z, 301500Z AND 302100Z.// ========================================================================= WTXS31 PGTW 20121230 09:00z MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 007// RMKS/ 1. TROPICAL CYCLONE 06S (MITCHELL) WARNING NR 007 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 300600Z --- NEAR 22.6S 110.0E MOVEMENT PAST SIX HOURS - 185 DEGREES AT 13 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 DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER REPEAT POSIT: 22.6S 110.0E --- FORECASTS: 12 HRS, VALID AT: 301800Z --- 25.1S 109.2E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 300900Z POSITION NEAR 23.2S 109.8E. TROPICAL CYCLONE (TC) 06S (MITCHELL), LOCATED APPROXIMATELY 225 NM WEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 13 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) INDICATES THAT TC 06S HAS CONTINUED TO WEAKEN RAPIDLY WITH LIMITED SHALLOW CONVECTION AND THE LOW LEVEL CIRCULATION CENTER HAS NOW BECOME FULLY EXPOSED. A 300457Z TRMM 85 GHZ MICROWAVE IMAGE CONCURS WITH THE MSI AND ADDITIONALLY SHOWS SOME DRY CONTINENTAL AIR BEING PULLED INTO THE SYSTEM, WHICH WILL FURTHER WEAKEN TC 06S. THE INITIAL INTENSITY OF 35 KNOTS IS BASED UPON FALLING DVORAK INTENSITY ESTIMATES AND THE OVERALL WEAKENING TREND SEEN IN IMAGERY. THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION BASED ON THE TRMM IMAGE AND THE MSI LOOP. TC 06S IS TRACKING SOUTHWARD TO SOUTH-SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF A DEEP SUBTROPICAL RIDGE, WHICH IS ENTRENCHED OVER WESTERN AUSTRALIA. TC 06S IS FORECAST TO WEAKEN THROUGHOUT THE FORECAST PERIOD AND SHOULD DISSIPATE BELOW WARNING THRESHOLD BY TAU 12 AS IT TRACKS OVER COOL SST (LESS THAN 24C) AND ENCOUNTERS INCREASING VERTICAL WIND SHEAR. 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. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 300600Z IS 15 FEET.//
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Document: tropical_cyclone_mitchell.htm | Updated: 1 January 2013 |