WTXS31 PGTW 242100
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 21S (IMANI) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 21S (IMANI) WARNING NR 005
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
241800Z --- NEAR 17.7S 85.5E
MOVEMENT PAST SIX HOURS - 195 DEGREES AT 10 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
040 NM SOUTHEAST QUADRANT
040 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
REPEAT POSIT: 17.7S 85.5E
---
FORECASTS:
12 HRS, VALID AT:
250600Z --- 19.3S 85.0E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
080 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 190 DEG/ 06 KTS
---
24 HRS, VALID AT:
251800Z --- 20.4S 84.8E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 185 DEG/ 05 KTS
---
36 HRS, VALID AT:
260600Z --- 21.4S 84.7E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 180 DEG/ 04 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
261800Z --- 22.2S 84.7E
MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
WIND RADII VALID OVER OPEN WATER ONLY
DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
---
REMARKS:
242100Z POSITION NEAR 18.1S 85.4E.
TROPICAL CYCLONE (TC) 21S (IMANI), LOCATED APPROXIMATELY 745 NM WEST-
SOUTHWEST OF COCOS ISLAND, HAS TRACKED SOUTH-SOUTHWESTWARD AT 10
KNOTS OVER THE PAST SIX HOURS. ANIMATED INFRARED SATELLITE IMAGERY
SHOWS A BANDING EYE WITH TIGHTLY-WRAPPED DEEP CONVECTION WHILE
RECENT MICROWAVE IMAGERY REVEALS A LOW-LEVEL EYE FEATURE. OVER THE
LAST 12 HOURS, THE SYSTEM HAS MAINTAINED AT 65-KNOTS DUE TO ENHANCED
POLEWARD OUTFLOW AHEAD OF A DIGGING MID-LATITUDE TROUGH. TC 21S IS
EXPECTED TO DRIFT GENERALLY SOUTHWARD ALONG THE WESTERN PERIPHERY OF
THE SUBTROPICAL STEERING RIDGE THROUGHOUT THE FORECAST PERIOD. AS
THE SYSTEM CONTINUES TO MOVE SOUTH, IT WILL START TO EXPERIENCE
HOSTILE VERTICAL WIND SHEAR CAUSED BY THE DIGGING UPPER-LEVEL TROUGH
TO THE WEST BY TAU 24 AND DISSIPATE AS A SIGNIFICANT TROPICAL
CYCLONE BY TAU 48. THE MODEL GUIDANCE IS IN GENERAL AGREEMENT WITH A
SOUTHWARD TRACK THOUGH SOME OF THE MODELS ERRONEOUSLY INITIALIZE A
WEAKER SYSTEM THAT WILL TRACK WITH THE LOW-LEVEL EASTERLY FLOW
(UKMO, ECMWF). MAXIMUM SIGNIFICANT WAVE HEIGHT AT 241800Z IS 17 FEET.
NEXT WARNINGS AT 250900Z AND 252100Z.//
NNNN
