WTIO32 PGTW 250900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 04B (NIVAR) WARNING NR 008// RMKS/ 1. TROPICAL CYCLONE 04B (NIVAR) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN NORTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 250600Z --- NEAR 11.2N 81.8E MOVEMENT PAST SIX HOURS - 295 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 075 NM SOUTHWEST QUADRANT 085 NM NORTHWEST QUADRANT REPEAT POSIT: 11.2N 81.8E --- FORECASTS: 12 HRS, VALID AT: 251800Z --- 12.1N 80.5E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 005 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 315 DEG/ 06 KTS --- 24 HRS, VALID AT: 260600Z --- 13.0N 79.6E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 325 DEG/ 05 KTS --- 36 HRS, VALID AT: 261800Z --- 13.8N 79.0E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 305 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 270600Z --- 14.5N 77.9E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 250900Z POSITION NEAR 11.4N 81.5E. 25NOV20. TROPICAL CYCLONE (TC) 04B (NIVAR), LOCATED APPROXIMATELY 782 NM SOUTH-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 POOR CONFIDENCE BASED ON THE UPPER LEVEL BANDING IN THE MSI LOOP. THE INITIAL INTENSITY OF 60 KTS IS PLACED WITH FAIR CONFIDENCE BASED ON A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T3.5 (55 KTS) AND A 250151Z CIMSS SATELLITE CONSENSUS INTENSITY ESTIMATE OF 62 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 PERSIST THROUGH LANDFALL AS THE SYSTEM TRACKS NORTHWESTWARD AROUND THE STEERING RIDGE AND WILL RESULT IN AN INTENSITY OF 70 KTS BY TAU 12. THEREAFTER, THE SYSTEM WILL INTENSIFY FURTHER AS FAVORABLE CONDITIONS PERSIST BEFORE MAKING LANDFALL SHORTLY AFTER TAU 12 SOUTH OF CHENNAI, INDIA. UPON MAKING LANDFALL, TC NIVAR WILL BEGIN TO RAPIDLY WEAKEN DUE TO INTERACTION WITH THE UNDERLYING TERRAIN AND INCREASING VWS. THIS COMBINATION OF FRICTIONAL EFFECTS AND MODERATE (15-20 KTS) VWS WILL LEAD TO DISSIPATION OVER LAND BY TAU 48. NUMERICAL MODEL TRACK GUIDANCE IS IN TIGHT AGREEMENT THROUGH LANDFALL WITH A MAXIMUM SPREAD IN SOLUTIONS OF 60 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 250600Z IS 20 FEET. NEXT WARNINGS AT 251500Z, 252100Z, 260300Z AND 260900Z. // NNNN