WTPS33 PGTW 120900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 04P (FOUR) WARNING NR 006// RMKS/ 1. TROPICAL CYCLONE 04P (FOUR) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 120600Z --- NEAR 15.8S 174.6E MOVEMENT PAST SIX HOURS - 235 DEGREES AT 18 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 RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 170 NM NORTHWEST QUADRANT REPEAT POSIT: 15.8S 174.6E --- FORECASTS: 12 HRS, VALID AT: 121800Z --- 16.0S 173.1E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 260 DEG/ 04 KTS --- 24 HRS, VALID AT: 130600Z --- 16.1S 172.3E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 250 DEG/ 02 KTS --- 36 HRS, VALID AT: 131800Z --- 16.2S 172.0E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT 140 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 150 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 235 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 140600Z --- 16.4S 171.7E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 160 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 200 DEG/ 01 KTS --- 72 HRS, VALID AT: 150600Z --- 16.7S 171.6E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 190 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 155 DEG/ 01 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 160600Z --- 16.9S 171.7E MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 090 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 180 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 190 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 125 DEG/ 06 KTS --- 120 HRS, VALID AT: 170600Z --- 18.2S 173.6E MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 050 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 110 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 250 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 170 NM SOUTHWEST QUADRANT 180 NM NORTHWEST QUADRANT --- REMARKS: 120900Z POSITION NEAR 15.8S 174.2E. 12DEC20. TROPICAL CYCLONE (TC) 04P (FOUR), LOCATED APPROXIMATELY 258 NM WEST-NORTHWEST OF SUVA, FIJI, HAS TRACKED SOUTHWESTWARD AT 18 KNOTS OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) REVEALS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING CONVECTION OVER THE SYSTEM CENTER. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE PARTIALLY EXPOSED NATURE OF THE LLCC AND THE LOW LEVEL BANDING FEATURES PRESENT IN A 120530Z SSMIS 37 GHZ COMPOSITE IMAGE. THE INITIAL INTENSITY IS ASSESSED AT 35 KTS WITH FAIR CONFIDENCE AND IS HEDGED SLIGHTLY HIGHER THAN A PGTW DVORAK CURRENT INTENSITY ESTIMATE OF T2.0 (30 KTS) AND A CIMSS ADVANCED DVORAK TECHNIQUE CURRENT INTENSITY ESTIMATE OF T2.2 (32 KTS). TC 04P IS TRANSITING THROUGH A MARGINAL ENVIRONMENT CONSISTING OF DIVERGENCE ALOFT AND WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURES OFFSET BY MODERATE (15-20 KTS) VERTICAL WIND SHEAR (VWS). THE SYSTEM IS TRACKING ALONG A SUBTROPICAL RIDGE (STR) POSITIONED TO THE SOUTH AND IS FORECAST TO CONTINUE TRACKING GENERALLY WEST TO WEST-SOUTHWESTWARD THROUGH THE NEXT 48 HOURS. DURING THIS TIME, A CONSOLIDATING MONSOON DEPRESSION, INVEST 91P, LOCATED TO THE NORTH-NORTHWEST WILL CONTINUE TO TRACK GENERALLY EASTWARD AND INTENSIFY INTO A TROPICAL CYCLONE. THE CLOSE PROXIMITY OF INVEST 91P TO TC 04P WILL LIKELY LEAD TO DIRECT CYCLONE INTERACTION (DCI) AND POSSIBLE FUJIWHARA EFFECTS NEAR TAU 48. THE COMPLEX INTERACTION BETWEEN THESE TWO SYSTEMS RESULTS IN HIGH UNCERTAINTY IN THE TRACK AND INTENSITY FORECAST AS MODELS CONTINUE TO STRUGGLE WITH A COHERENT SOLUTION. GFS AND ECMWF SOLUTIONS MERGE THE TWO SYSTEMS INTO ONE TROPICAL CYCLONE BETWEEN TAUS 24 AND 48 THAT THEN REMAINS LARGELY QUASI- STATIONARY THROUGH TAU 96 WITH A SUBSEQUENT TRACK SOUTHEASTWARD TOWARDS FIJI THROUGH TAU 120. THE GALWEM, JGSM, UKMET AND NAVGEM MODEL SOLUTIONS, ON THE OTHER HAND, DEPICT SHORT TERM DCI THAT RESULTS IN TWO SEPARATE VORTEX CENTERS WITH SUBSEQUENT DISSIPATION. THE JTWC FORECAST TRACK IS PLACED NEAR THE GFS AND ECMWF SOLUTIONS WHICH REFLECT THE MERGER BETWEEN THE SYSTEMS AND RESULTING SOUTHEASTWARD TRACK. THE SYSTEM IS FORECAST TO GRADUALLY INTENSIFY THROUGHOUT THE FORECAST PERIOD AND REACH AN INTENSITY OF 85 KTS BY TAU 120. THE COMPLEX NATURE OF THE INTERACTION BETWEEN THE TWO CYCLONES AND HIGH DEGREE OF UNCERTAINTY IN MODEL SOLUTIONS LENDS OVERALL LOW CONFIDENCE IN THE OVERALL JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 120600Z IS 14 FEET. NEXT WARNINGS AT 121500Z, 122100Z, 130300Z AND 130900Z. // NNNN