WTIO32 PGTW 251500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 04B (NIVAR) WARNING NR 009// RMKS/ 1. TROPICAL CYCLONE 04B (NIVAR) WARNING NR 009 01 ACTIVE TROPICAL CYCLONE IN NORTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 251200Z --- NEAR 11.6N 81.0E MOVEMENT PAST SIX HOURS - 295 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND RADAR PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 005 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT REPEAT POSIT: 11.6N 81.0E --- FORECASTS: 12 HRS, VALID AT: 260000Z --- 12.5N 79.9E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 064 KT WINDS - 000 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 005 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 315 DEG/ 05 KTS --- 24 HRS, VALID AT: 261200Z --- 13.2N 79.2E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 330 DEG/ 05 KTS --- 36 HRS, VALID AT: 270000Z --- 14.0N 78.7E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 305 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 271200Z --- 14.7N 77.6E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 251500Z POSITION NEAR 11.8N 80.7E. 25NOV20. TROPICAL CYCLONE (TC) 04B (NIVAR), LOCATED APPROXIMATELY 784 NM SOUTHWEST OF KOLKATA, INDIA, HAS TRACKED WEST-NORTHWESTWARD AT 09 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS SPIRAL BANDS OF DEEP CONVECTION WRAPPING INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE CONVECTIVE STRUCTURES PRESENT IN A TIMELY 251205Z GMI 37 GHZ IMAGE AND THE LOW LEVEL RAIN BANDS THAT WRAP AROUND THE LLCC IN THE COMPOSITE RADAR LOOP. THE INITIAL INTENSITY OF 70 KTS IS PLACED WITH FAIR CONFIDENCE AND IS HEDGED SLIGHTLY BELOW A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T4.5 (77 KTS) BASED ON A LOWER 250814Z CIMSS SATELLITE CONSENSUS INTENSITY ESTIMATE OF 50 KTS. TC NIVAR IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF A DEEP LAYER SUBTROPICAL RIDGE POSITIONED TO THE NORTHEAST AND THROUGH A FAVORABLE ENVIRONMENT FOR DEVELOPMENT WITH WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES (SST), LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND ROBUST POLEWARD AND MODERATE EQUATORWARD OUTFLOW ALOFT. THESE FAVORABLE ENVIRONMENTAL CONDITIONS WILL ALLOW FOR FURTHER INTENSIFICATION AS THE SYSTEM TRACKS NORTHWESTWARD ALONG THE STEERING RIDGE BEFORE MAKING LANDFALL JUST PRIOR TO TAU 12. AFTER MAKING LANDFALL SOUTH OF CHENNAI, INDIA, TC NIVAR WILL BEGIN TO RAPIDLY WEAKEN DUE TO INTERACTION WITH THE UNDERLYING TERRAIN. INCREASING VWS AFTER TAU 24, ALONG WITH TERRAIN EFFECTS, WILL LEAD TO FURTHER WEAKENING AND RESULT IN DISSIPATION OVER LAND BY TAU 48. NUMERICAL MODEL TRACK GUIDANCE IS IN TIGHT AGREEMENT THROUGH LANDFALL WITH A MAXIMUM SPREAD IN SOLUTIONS OF 34 NM AT THAT TIME. THEREAFTER, MODEL SOLUTIONS DIVERGE WITH THE UKMET SOLUTIONS PROVIDING A NORTHWARD TRACK THAT BRINGS THE VORTEX BACK INTO THE BAY OF BENGAL, IN CONTRAST TO THE REMAINING MULTI-MODEL CONSENSUS MEMBERS THAT BRING THE SYSTEM CENTER INLAND. DESPITE THIS SPREAD IN THE LATER TAUS, THIS MODEL GUIDANCE LENDS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED JUST SOUTH OF THE MULTI-MODEL CONSENSUS IN EFFORT TO OFFSET THE NORTHWARD BIAS OF THE UKMET MODEL SOLUTIONS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 251200Z IS 23 FEET. NEXT WARNINGS AT 252100Z, 260300Z, 260900Z AND 261500Z.// NNNN