WTIO32 PGTW 252100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 04B (NIVAR) WARNING NR 010// RMKS/ 1. TROPICAL CYCLONE 04B (NIVAR) WARNING NR 010 01 ACTIVE TROPICAL CYCLONE IN NORTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 251800Z --- NEAR 12.0N 80.1E MOVEMENT PAST SIX HOURS - 295 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 050 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 - 030 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 095 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT REPEAT POSIT: 12.0N 80.1E --- FORECASTS: 12 HRS, VALID AT: 260600Z --- 12.9N 79.1E 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 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 315 DEG/ 05 KTS --- 24 HRS, VALID AT: 261800Z --- 13.6N 78.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 36 HR POSIT: 300 DEG/ 04 KTS --- 36 HRS, VALID AT: 270600Z --- 14.0N 77.7E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 252100Z POSITION NEAR 12.2N 79.8E. 25NOV20. TROPICAL CYCLONE (TC) 04B (NIVAR), LOCATED APPROXIMATELY 794 NM SOUTHWEST OF KOLKATA, INDIA, HAS TRACKED WEST- NORTHWESTWARD AT 10 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY (EIR) DEPICTS DEEP CONVECTION OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC). THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON EXTRAPOLATION USING A 251601Z MHS 89GHZ MICROWAVE IMAGE AND THE EIR. THE INITIAL INTENSITY OF 70 KTS IS BASED ON RECENT MULTI-AGENCY PGTW/DEMS DVORAK CURRENT INTENSITY ESTIMATES OF T4.0-4.5 (65-77 KTS). THE SYSTEM IS CONTINUING TO TRACK ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST AND THROUGH A FAVORABLE ENVIRONMENT WITH LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS), STRONG POLEWARD OUTFLOW AND WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURES (SST). SINCE THE INITIAL POSITION, TC NIVAR MAY HAVE TRACKED OVER LAND, MAKING LANDFALL SOUTH OF CHENNAI. THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD, THE SYSTEM SHOULD MOVE GENERALLY NORTHWESTWARD STEADILY WEAKENING DUE TO INTERACTION WITH THE UNDERLYING TERRAIN AND INCREASING VERTICAL WIND SHEAR. FULL DISSIPATION IS ANTICIPATED BY TAU 36 AND THERE IS LOW PROBABILITY OF THE SYSTEM REGENERATING OVER THE ARABIAN SEA. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH TAU 12. UKMET AND UKMET ENSEMBLE MODEL SOLUTIONS TRACK THE SYSTEM NORTHWARD WHILE THE OTHER MODELS TRACK GENERALLY NORTHWESTWARD THROUGH THE FORECAST PERIOD. OVERALL, MODEL GUIDANCE LENDS GOOD CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED JUST SOUTH OF AND SLIGHTLY FASTER THAN THE MULTI-MODEL CONSENSUS TO OFFSET THE UKMET TRACKS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 252100Z IS 24 FEET. NEXT WARNINGS AT 260300Z, 260900Z, 261500Z AND 262100Z.// NNNN