WTXS31 PGTW 042100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 03S (AVA) WARNING NR 009// RMKS/ 1. TROPICAL CYCLONE 03S (AVA) WARNING NR 009 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 041800Z --- NEAR 17.3S 51.0E MOVEMENT PAST SIX HOURS - 285 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 045 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 - 035 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 095 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 095 NM NORTHWEST QUADRANT REPEAT POSIT: 17.3S 51.0E --- FORECASTS: 12 HRS, VALID AT: 050600Z --- 17.6S 50.1E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 010 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT 165 NM SOUTHEAST QUADRANT 105 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 220 DEG/ 05 KTS --- 24 HRS, VALID AT: 051800Z --- 18.3S 49.5E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 195 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 095 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 195 DEG/ 07 KTS --- 36 HRS, VALID AT: 060600Z --- 19.6S 49.1E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 185 NM NORTHEAST QUADRANT 195 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 185 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 061800Z --- 21.0S 49.0E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 025 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT 215 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 175 DEG/ 06 KTS --- 72 HRS, VALID AT: 071800Z --- 23.4S 49.2E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT 220 NM SOUTHEAST QUADRANT 160 NM SOUTHWEST QUADRANT 105 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 200 DEG/ 05 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 081800Z --- 25.2S 48.4E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT 045 NM SOUTHEAST QUADRANT 025 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 045 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 165 NM NORTHEAST QUADRANT 190 NM SOUTHEAST QUADRANT 135 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 200 DEG/ 05 KTS --- 120 HRS, VALID AT: 091800Z --- 27.2S 47.5E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY BECOMING EXTRATROPICAL RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 075 NM SOUTHEAST QUADRANT 055 NM SOUTHWEST QUADRANT 055 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 175 NM NORTHEAST QUADRANT 180 NM SOUTHEAST QUADRANT 170 NM SOUTHWEST QUADRANT 165 NM NORTHWEST QUADRANT --- REMARKS: 042100Z POSITION NEAR 17.4S 50.8E. TROPICAL CYCLONE 03S (AVA), LOCATED APPROXIMATELY 311 NM NORTHWEST OF ST DENIS, HAS TRACKED WEST-NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. A 041519Z 37GHZ SSMIS MICROWAVE IMAGE SHOWING DEEP CONVECTION PREDOMINANTLY IN THE NORTHEAST QUADRANT AND CONVECTIVE BANDING WRAPPING INTO THE LOW LEVEL CIRCULATION CENTER. THE INITIAL INTENSITY OF 60 KNOTS IS BASED ON DVORAK CURRENT INTESITY ESTIMATES OF T3.5 TO T4.0 (55-65 KNOTS) FROM PGTW AND KNES RESPECTIVELY. ENVIRONMENTAL ANALYSIS REVEALS A MODERATELY FAVORABLE ENVIRONMENT WITH LOW (10 TO 15 KNOTS) VERTICAL WIND SHEAR (VWS) AND WARM (28-29 CELSIUS) SEA SURFACE TEMPERATURES. UPPER LEVEL ANALYSIS SHOWS THE SYSTEM HAS BOTH A STRONG EQUATORWARD OUTFLOW CHANNEL AND A MODERATE POLEWARD OUTFLOW CHANNEL. TC 03S IS INITIALLY FORECASTED TO TRACK WEST-SOUTHWEST THROUGH TAU 24 ALONG THE NORTHEASTERN PERIPHERY OF A BUILDING SUB-TROPICAL STEERING RIDGE (STR). AFTER TAU 24, THE STR WILL BEGIN TO MOVE EASTWARD, ALLOWING TC AVA TO TRACK TO THE SOUTH ALONG THE WESTERN EXTENT OF THE STR, TRACKING DOWN THE EAST COAST OF MADAGASCAR. THE SOUTHERLY TRACK WILL PERSIST UNTIL AROUND TAU 72 WHEN THE STR, NOW LOCATED TO THE SOUTHEAST, WILL BUILD BACK WESTWARD CAUSING TC 03S TO TRACK TO THE SOUTHWEST. TC 03S IS FORECAST TO REACH A PEAK INTENSITY OF 70 KNOTS BY TAU 12. AFTER TAU 12, THE SYSTEM WILL BEGIN TO INTERACT WITH LAND, WHICH WILL BRIEFLY WEAKEN THE SYSTEM THROUGH TAU 36. AFTER TAU 36, THE SYSTEM WILL TRACK FARTHER OFFSHORE WHERE MODERATELY FAVORABLE CONDITIONS WILL ALLOW THE SYSTEM TO RE-INTENSIFY TO A PEAK OF 65 KNOTS THROUGH TAU 96. AFTER TAU 96, INCREASING VERTICAL WIND SHEAR AND DECREASING SEA SURFACE TEMPERATURES WILL BEGIN TO WEAKEN THE SYSTEM. AROUND TAU 120, A PASSING LONGWAVE TROUGH WILL INTRODUCE INCREASED VERTICAL WIND SHEAR AND COLD AIR ADVECTION THAT WILL BEGIN TO WEAKEN THE SYSTEM. DYNAMIC MODEL GUIDANCE SHOWS STRONG AGREEMENT THROUGH TAU 24. AFTERWARD, SOLUTIONS BEGIN TO SPREAD SIGNIFICANTLY IN BOTH SPEED AND DIRECTION RELATED TO VARIATIONS IN THE TIMING AND EXTENT OF THE RIDGE MODIFICATIONS. THE PRINCIPLE OUTLIERS ARE NAVGEM AND JGSM WITH SOLUTIONS THAT SUGGEST A SHARP TURN SOUTH PRIOR TO TAU 12 AND A TRACK SIGNIFICANTLY FARTHER FROM THE MADAGASCAR COAST. DUE TO THE SIGNIFICANT SPREAD IN MODEL GUIDANCE, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 041800Z IS 18 FEET. NEXT WARNINGS AT 050300Z, 050900Z, 051500Z AND 052100Z.//