WTIO32 PGTW 240900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 04B (NIVAR) WARNING NR 004// RMKS/ 1. TROPICAL CYCLONE 04B (NIVAR) WARNING NR 004 02 ACTIVE TROPICAL CYCLONES IN NORTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 240600Z --- NEAR 9.5N 82.8E MOVEMENT PAST SIX HOURS - 270 DEGREES AT 05 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 - 030 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT REPEAT POSIT: 9.5N 82.8E --- FORECASTS: 12 HRS, VALID AT: 241800Z --- 9.8N 82.0E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 305 DEG/ 06 KTS --- 24 HRS, VALID AT: 250600Z --- 10.5N 80.9E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 310 DEG/ 06 KTS --- 36 HRS, VALID AT: 251800Z --- 11.3N 79.9E MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 010 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 305 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 260600Z --- 12.0N 78.9E 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 - 100 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 310 DEG/ 05 KTS --- 72 HRS, VALID AT: 270600Z --- 13.2N 77.3E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 240900Z POSITION NEAR 9.6N 82.6E. 24NOV20. TROPICAL CYCLONE 04B (NIVAR), LOCATED APPROXIMATELY 849 NM SOUTH-SOUTHWEST OF KOLKATA, INDIA, HAS TRACKED WESTWARD AT 05 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS AN ASYMMETRIC SYSTEM WITH CONVECTION DISPLACED WEST OF THE LOW-LEVEL CIRCULATION CENTER (LLCC), HOWEVER SIGNIFICANT CONSOLIDATION OF THE CONVECTION HAS BEEN NOTED OVER THE PAST 6 HOURS. THE INITIAL POSITION IS PLACED WITH FAIR CONFIDENCE BASED ON THE BANDING FEATURES PRESENT IN THE MSI LOOP AS WELL AS THE LOW LEVEL CONVECTIVE BANDS THAT ARE EVIDENT IN A 240336Z METOP-B 89GHZ IMAGE. THE INITIAL INTENSITY IS ASSESSED AT 45 KNOTS AND IS IN AGREEMENT WITH A PGTW DVORAK INTENSITY ESTIMATE OF T3.0 (45 KNOTS), A 240335Z SATCON INTENSITY ESTIMATE OF 46 KNOTS AND THE 40 KTS WINDS PRESENT IN A 240336Z ASCAT-B PASS. THE SYSTEM IS TRACKING ALONG THE SOUTHWESTERN PERIPHERY OF THE SUBTROPICAL RIDGE (STR) POSITIONED TO THE NORTHEAST AND THROUGH A FAVORABLE ENVIRONMENT WITH LOW VERTICAL WIND SHEAR, ROBUST POLEWARD OUTFLOW AND WARM 929-30 CELSIUS) SEA SURFACE TEMPERATURES (SST). TC NIVAR IS FORECAST TO BEGIN A GENERALLY NORTHWESTWARD TRACK IN THE NEAR TERM AS A MID-LATITUDE TROUGH APPROACHING FROM THE NORTHWEST DIGS INTO AND WEAKENS THE AFOREMENTIONED STR. OF NOTE, THIS WEAKENING OF THE RIDGE MAY ALLOW FOR INCREASED POLEWARD OUTFLOW AND SUBSEQUENT RAPID INTENSIFICATION. THIS INCREASED OUTFLOW, COUPLED WITH FAVORABLE VWS AND SST, WILL ALOW THE SYSTEM TO FUTHER INTENSIFY THROUGH TAU 24 AT WHICH TIME IT WILL REACH AN INTENSITY OF 70 KTS. SLIGHTLY HIGHER VERTICAL WIND SHEAR AND COOLER SST THEREAFTER WILL SUPPORT GRADUAL INTENSIFICATION TO 75 KTS BY TAU 36. SHORTLY THEREAFTER THE SYSTEM WILL MAKE LANDFALL ALONG THE EASTERN COAST OF INDIA, SOUTH OF CHENNAI. INTERACTION WITH THE UNDERLYING TERRAIN WILL LEAD TO RAPID WEAKENING TO 45 KTS BY TAU 48 AS THE SYSTEM BEGINS DISSIPATION OVER LAND AND FULL DISSIPATION OVER LAND BY TAU 72. THE REMNANTS OF TC 04B MAY TRACK OVER THE ARABIAN SEA, HOWEVER, THERE IS LOW PROBABILITY OF REGENERATION. NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT WITH A SPREAD OF 93 NAUTICAL MILES AT LANDFALL, HOWEVER THIS AGREEMENT BECOMES POOR THEREAFTER AS THE SPREAD INCREASES TO 364 NAUTICAL MILES BY TAU 72. THIS WIDER SPREAD IS LARGELY DUE TO UKMET MODEL SOLUTIONS WHICH TURN THE SYSTEM SHARPLY TO THE RIGHT AT LANDFALL. OVERALL, MODEL GUIDANCE LENDS ONLY FAIR CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED JUST SOUTH OF THE MULTI-MODEL CONSENSUS TO OFFSET THE UKMET TRACKS. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 240600Z IS 17 FEET. NEXT WARNINGS AT 241500Z, 242100Z, 250300Z AND 250900Z. REFER TO TROPICAL CYCLONE 03A (GATI) WARNINGS (WTIO31 PGTW) FOR SIX-HOURLY UPDATES. // NNNN