WTIO31 PGTW 082100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 04B (FOUR) WARNING NR 001// REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/080136ZDEC17// AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.// RMKS/ 1. TROPICAL CYCLONE 04B (FOUR) WARNING NR 001 01 ACTIVE TROPICAL CYCLONE IN NORTH IO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 081800Z --- NEAR 18.3N 86.8E MOVEMENT PAST SIX HOURS - 005 DEGREES AT 15 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT REPEAT POSIT: 18.3N 86.8E --- FORECASTS: 12 HRS, VALID AT: 090600Z --- 19.8N 87.1E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 020 DEG/ 08 KTS --- 24 HRS, VALID AT: 091800Z --- 21.2N 87.7E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 010 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 040 DEG/ 09 KTS --- 36 HRS, VALID AT: 100600Z --- 22.6N 88.9E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 082100Z POSITION NEAR 18.7N 86.9E. TROPICAL CYCLONE 04B (FOUR), LOCATED APPROXIMATELY 370 NM SOUTHWEST OF CHITTAGONG, BANGLADESH, HAS TRACKED NORTHWARD AT 15 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS FLARING CONVECTION TO THE NORTH OF THE LOW LEVEL CIRCULATION CENTER (LLCC) ASSOCIATED WITH TC 04B. THE INITIAL INTENSITY OF 40 KNOTS IS BASED ON A 081514Z ASCAT IMAGE SHOWING AN AREA OF 40 KNOT WINDS IN THE WESTERN SEMICIRCLE OF TC 04B. ENVIRONMENTAL ANALYSIS SHOWS FAVORABLE VERTICAL WIND SHEAR VALUES (10 TO 15 KNOTS) TO THE SOUTH OF TC 04B. HOWEVER, AS TC 04B TRACKS NORTH-NORTHEASTWARD IT WILL ENCOUNTER UNFAVORABLE VERTICAL WIND SHEAR VALUES (25 TO 30 KNOTS). POLEWARD OUTFLOW IS MODERATE AND EQUATORWARD OUTFLOW IS POOR. SEA SURFACE TEMPERATURES ARE UNFAVORABLE (25 TO 26 DEGREES CELSIUS). TC 04B IS UNDER THE STEERING INFLUENCE OF A SUBTROPICAL RIDGE (STR) LOCATED TO THE EAST. THE STR WILL STEER TC 04B NORTH-NORTHEASTWARD THROUGH TAU 36. AS A RESULT OF UNFAVORABLE ENVIRONMENTAL CONDITIONS TC 04B WILL WEAKEN IN INTENSITY TO 35 KNOTS BY TAU 24 BEFORE DISSIPATING OVER LAND BY TAU 36. DYNAMIC MODEL GUIDANCE IS IN GOOD AGREEMENT RESULTING IN HIGH CONFIDENCE IN THE JTWC TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 081800Z IS 15 FEET. NEXT WARNINGS AT 090300Z, 090900Z, 091500Z AND 092100Z. THIS CANCELS AND SUPERSEDES REF A (WTIO21 PGTW 080030 COR).//