Tropical Cyclones [Index]

Tropical Cyclone NEIL Southern Hemisphere Summary

WTPS21 PGTW 091230
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE FORMATION ALERT (INVEST 91P)//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
165 NM EITHER SIDE OF A LINE FROM 17.1S 176.5W TO 27.7S 174.1W
WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY
ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME.
WINDS IN THE AREA ARE ESTIMATED TO BE 30 TO 35 KNOTS. METSAT
IMAGERY AT 090600Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 18.0S 176.2W. THE SYSTEM IS MOVING SOUTHEASTWARD AT 17
KNOTS.
2. REMARKS: THE AREA OF CONVECTION (INVEST 91P) PREVIOUSLY LOCATED
NEAR 16.1S 177.7W, IS NOW LOCATED NEAR 18.0S 176.2W, APPROXIMATELY
390 NM SOUTHWEST OF PAGO PAGO, AMERICAN SAMOA. ANIMATED ENHANCED
INFRARED SATELLITE IMAGERY AND A 090656Z 91GHZ SSMIS MICROWAVE
SATELLITE IMAGE SHOW A SLIGHTLY ELONGATED LOW LEVEL CIRCULATION
CENTER (LLCC) PARTIALLY OBSCURED BY PERSISTENT DEEP CONVECTION
SHEARED TO THE EAST. A  091000Z PARTIAL ASCAT PASS SHOWS
PREDOMINANTLY 30KT WINDS WRAPPING AROUND THE LLCC WITH OCCASIONAL
35KT WIND BARBS. THE AFOREMENTIONED SHEAR IS CURRENTLY HIGH (25-
40KTS) BUT IS OFFSET BY STRONG UPPER LEVEL DIVERGENCE DUE TO BROAD
WESTERLY OUTFLOW. SEA SURFACE TEMPERATURES ARE STILL FAVORABLE FOR
TROPICAL DEVELOPMENT (27-29C) BUT 91P IS EXPECTED TO SOON CROSS INTO
UNFAVORABLY COOL (<26C) WATERS. GLOBAL MODELS AGREE ON A SOUTHWARD
TRACK WITH SOME ALONG-TRACK SPREAD. THE SYSTEM IS CURRENTLY
EXHIBITNG SUBTROPICAL CHARACTERISTICS, BUT GIVEN THE CURRENT STATE
OF THE LOW LEVEL WIND FIELD THERE IS STILL SIGNIFICANT POTENTIAL FOR
91P TO BECOME TROPICAL WITHIN THE NEXT 24 HOURS. MAXIMUM SUSTAINED
SURFACE WINDS ARE ESTIMATED AT 30 TO 35 KNOTS. MINIMUM SEA LEVEL
PRESSURE IS ESTIMATED TO BE NEAR 996 MB. THE POTENTIAL FOR THE
DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS HIGH.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
101230Z.//
========================================================================
WTPS31 PGTW 092100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 14P (NEIL) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/091221ZFEB2019//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 14P (NEIL) WARNING NR 001
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   091800Z --- NEAR 20.9S 174.9W
     MOVEMENT PAST SIX HOURS - 160 DEGREES AT 17 KTS
     POSITION ACCURATE TO WITHIN 020 NM
     POSITION BASED ON CENTER LOCATED BY A COMBINATION OF
     SATELLITE AND SYNOPTIC DATA
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            125 NM SOUTHEAST QUADRANT
                            045 NM SOUTHWEST QUADRANT
                            130 NM NORTHWEST QUADRANT
   REPEAT POSIT: 20.9S 174.9W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   100600Z --- 24.5S 173.6W
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
                            160 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 160 DEG/ 23 KTS
    ---
   24 HRS, VALID AT:
   101800Z --- 28.8S 171.6W
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            170 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 160 DEG/ 27 KTS
    ---
   36 HRS, VALID AT:
   110600Z --- 33.8S 169.5W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
092100Z POSITION NEAR 21.8S 174.6W.
TROPICAL CYCLONE (TC) 14P (NEIL), LOCATED APPROXIMATELY 302 NM WEST-
SOUTHWEST OF NIUE, HAS TRACKED SOUTH-SOUTHEASTWARD AT 17 KNOTS OVER
THE PAST SIX HOURS. TC 14P HAS TRANSITIONED INTO A WEAK WARM-CORE
TROPICAL CYCLONE. A 090849Z ASCAT IMAGE INDICATES AN ELONGATED BUT
DEFINED CIRCULATION WITH 30 TO 35 KNOT WINDS OVER THE EASTERN
SEMICIRCLE AND A RADIUS OF MAXIMUM WINDS NEAR 35NM, WHICH IS MORE
TYPICAL OF A TC. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A
DEFINED, FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER (LLCC) WITH
PERSISTENT DEEP CONVECTION SHEARED 80 TO 90NM EAST DUE TO STRONG
WESTERLY VERTICAL WIND SHEAR. A 091726Z GMI 36GHZ MICROWAVE IMAGE
INDICATES IMPROVED YET SOMEWHAT FRAGMENTED SHALLOW BANDING OVER THE
WESTERN SEMICIRCLE WRAPPING INTO THE LLCC. OVERALL, THERE IS GOOD
CONFIDENCE IN THE INITIAL POSITION. THE INITIAL INTENSITY IS
ASSESSED AT 35 KNOTS BASED ON THE ASCAT DATA AS WELL AS DVORAK
CURRENT INTENSITY ESTIMATES OF 2.5 (35 KNOTS) FROM PGTW AND NFFN. TC
14P IS FORECAST TO TRACK SOUTH-SOUTHEASTWARD THROUGH THE FORECAST
PERIOD UNDER THE STEERING INFLUENCE OF A LOW- TO MID-LEVEL
SUBTROPICAL RIDGE POSITIONED TO THE EAST. THE SYSTEM IS FORECAST TO
REMAIN A WEAK TC AS IT TRACKS INTO THE SUBTROPICAL WESTERLIES AND
OVER COOL SST (LESS THAN 25C). TC 14P SHOULD DISSIPATE BY TAU 36 BUT
COULD DISSIPATE MORE RAPIDLY DUE TO THE MARGINAL ENVIRONMENTAL
CONDITIONS. NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT,
THEREFORE THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 091800Z IS 10 FEET. NEXT WARNINGS
AT 100300Z, 100900Z, 101500Z AND 102100Z.
2. THIS CANCELS AND SUPERSEDES REF A (WTPS21 PGTW 091230).//
========================================================================
WTPS31 PGTW 100300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 14P (NEIL) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 14P (NEIL) WARNING NR 002
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   100000Z --- NEAR 22.6S 174.5W
     MOVEMENT PAST SIX HOURS - 170 DEGREES AT 17 KTS
     POSITION ACCURATE TO WITHIN 020 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 - 145 NM NORTHEAST QUADRANT
                            135 NM SOUTHEAST QUADRANT
                            000 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   REPEAT POSIT: 22.6S 174.5W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   101200Z --- 26.9S 172.4W
   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 - 190 NM NORTHEAST QUADRANT
                            120 NM SOUTHEAST QUADRANT
                            000 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 160 DEG/ 29 KTS
    ---
   24 HRS, VALID AT:
   110000Z --- 32.2S 169.8W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
100300Z POSITION NEAR 23.7S 174.0W.
TROPICAL CYCLONE (TC) 14P (NEIL), LOCATED APPROXIMATELY 333 NM
SOUTHWEST OF NIUE, HAS TRACKED SOUTHWARD AT 17 KNOTS OVER THE PAST
SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY DEPICTS A WELL-
DEFINED, FULLY-EXPOSED LOW-LEVEL CIRCULATION CENTER WITH DEEP
CONVECTION SHEARED TO THE EAST DUE TO STRONG WESTERLY VERTICAL WIND
SHEAR. OVERALL, THERE IS GOOD CONFIDENCE IN THE INITIAL POSITION. A
092035Z ASCAT-C BULLSEYE SHOWS A SYMMETRIC CIRCULATION WITH
EXTENSIVE 30 TO 35 KNOT WINDS OVER THE EASTERN SEMICIRCLE AND 15 TO
25 KNOT WINDS OVER THE WESTERN SEMICIRCLE. BASED ON THE ASCAT IMAGE,
THE RADIUS OF MAXIMUM WINDS IS ABOUT 40NM, WHICH REFLECTS THE
COMPACT, COHESIVE NATURE OF THIS WEAK TROPICAL CYCLONE. THE INITIAL
INTENSITY REMAINS ASSESSED AT 35 KNOTS BASED ON THE ASCAT DATA. TC
14P IS FORECAST TO TRACK SOUTH-SOUTHEASTWARD THROUGH THE FORECAST
PERIOD UNDER THE STEERING INFLUENCE OF A LOW- TO MID-LEVEL
SUBTROPICAL RIDGE POSITIONED TO THE EAST. THE SYSTEM IS FORECAST TO
REMAIN A WEAK TC AS IT TRACKS INTO THE SUBTROPICAL WESTERLIES AND
OVER COOL SST (LESS THAN 25C). TC 14P SHOULD DISSIPATE BY TAU 24 BUT
COULD DISSIPATE MORE RAPIDLY DUE TO THE MARGINAL ENVIRONMENTAL
CONDITIONS. NUMERICAL MODEL GUIDANCE IS IN TIGHT AGREEMENT,
THEREFORE THERE IS HIGH CONFIDENCE IN THE JTWC FORECAST TRACK.
MAXIMUM SIGNIFICANT WAVE HEIGHT AT 100000Z IS 10 FEET. NEXT WARNINGS
AT 100900Z, 101500Z AND 102100Z.//
========================================================================
WTPS31 PGTW 100900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 14P (NEIL) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 14P (NEIL) WARNING NR 003
   01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   100600Z --- NEAR 24.0S 173.9W
     MOVEMENT PAST SIX HOURS - 160 DEGREES AT 15 KTS
     POSITION ACCURATE TO WITHIN 020 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   REPEAT POSIT: 24.0S 173.9W
    ---
   FORECASTS:
   12 HRS, VALID AT:
   101800Z --- 28.5S 171.7W
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
100900Z POSITION NEAR 25.1S 173.4W.
TROPICAL CYCLONE 14P (NEIL), LOCATED APPROXIMATELY 369 NM
SOUTHWEST OF NIUE, HAS TRACKED SOUTH-SOUTHEASTWARD AT 15 KNOTS
OVER THE PAST SIX HOURS.
THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON
WRNCEN PEARL HARBOR HI. THE SYSTEM WILL BE CLOSELY MONITORED FOR
SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 100600Z
IS 12 FEET.