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Tropical Cyclone CHERONO : JTWC Advisories
Season 2010-2011 Summaries (Operational Data): [AU] [SIO] [SPAC] [SH]
---> Tropical Cyclone CHERONO Track Map and Data

WTXS21 PGTW 20110316 22:30z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN
160 NM EITHER SIDE OF A LINE FROM 14.4S 80.0E TO 16.3S 73.1E
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 27 TO 32 KNOTS. METSAT IM-
AGERY AT 161730Z INDICATES THAT A CIRCULATION CENTER IS LOCATED
NEAR 14.6S 79.6E.  THE SYSTEM IS MOVING WEST-SOUTHWESTWARD AT 12
KNOTS.
2. REMARKS: THE AREA OF CONVECTION PREVIOUSLY LOCATED NEAR 13.2S
83.6E, IS NOW LOCATED NEAR 14.2S 80.3E, APPROXIMATELY 600 NM
SOUTHEAST OF DIEGO GARCIA. ANIMATED INFRARED SATELLITE IMAGERY SHOWS
THAT CONVECTION HAS DEVELOPED OVER THE LOW LEVEL CIRCULATION CENTER
(LLCC) DURING THE PAST FEW HOURS. FORMATIVE BANDING WRAPPING INTO A
WELL-DEFINED LLCC IS ALSO APPARENT ON A 16/1957Z AMSR MICROWAVE
IMAGE. UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS LOCATED JUST
EQUATORWARD OF THE RIDGE AXIS IN AN AREA OF MODERATE (15 TO 20
KNOTS) VERTICAL WIND SHEAR AND GOOD POLEWARD OUTFLOW. SEA SURFACE
TEMPERATURES (>28 DEGREES CELSIUS) REMAIN FAVORABLE. MINIMUM SEA
LEVEL PRESSURE IS ESTIMATED TO BE NEAR 1000 MB. THE POTENTIAL FOR
THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE WITHIN THE NEXT 24
HOURS IS GOOD.
3. THIS ALERT WILL BE REISSUED, UPGRADED TO WARNING OR CANCELLED BY
172230Z.
=========================================================================
WTXS31 PGTW 20110317 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 001//
REF/A/NAVMARFCSTCEN PEARL HARBOR HI/162221Z MAR 11//
AMPN/TROPICAL CYCLONE FORMATION ALERT//
RMKS/
1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 001
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   170600Z --- NEAR 14.8S 76.3E
     MOVEMENT PAST SIX HOURS - 260 DEGREES AT 14 KTS
     POSITION ACCURATE TO WITHIN 060 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
   REPEAT POSIT: 14.8S 76.3E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   171800Z --- 15.1S 74.1E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 255 DEG/ 10 KTS
    ---
   24 HRS, VALID AT:
   180600Z --- 15.6S 72.0E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 045 NM NORTHEAST QUADRANT
                            055 NM SOUTHEAST QUADRANT
                            055 NM SOUTHWEST QUADRANT
                            045 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 245 DEG/ 10 KTS
    ---
   36 HRS, VALID AT:
   181800Z --- 16.4S 70.0E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 245 DEG/ 11 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   190600Z --- 17.3S 67.8E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            025 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 240 DEG/ 13 KTS
    ---
   72 HRS, VALID AT:
   200600Z --- 19.6S 63.1E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            025 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 235 DEG/ 12 KTS
    ---
   LONG RANGE OUTLOOK:
   NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
   ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
   NEAR 20 KT EACH DAY.
    ---
   96 HRS, VALID AT:
   210600Z --- 22.2S 58.7E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 120 HR POSIT: 220 DEG/ 11 KTS
    ---
   120 HRS, VALID AT:
   220600Z --- 25.4S 55.7E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
REMARKS:
170900Z POSITION NEAR 14.9S 75.7E.
TROPICAL CYCLONE (TC) 18S, LOCATED APPROXIMATELY 500 NM SOUTH-
SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WESTWARD AT 14 KNOTS DURING
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI)
SHOWS CONVECTIVE BANDING WRAPPING INTO A LOW LEVEL CIRCULATION
CENTER ASSOCIATED WITH IMPROVED DEEP CONVECTION. THE INITIAL
POSITION IS BASED ON THE MSI AND INTERPOLATED FROM A 170307Z SSMIS
MICROWAVE IMAGE. THE INITIAL INTENSITY IS BASED ON PGTW AND KNES
DVORAK ESTIMATES OF 35 KNOTS. UPPER LEVEL ANALYSIS INDICATES THE
SYSTEM IS LOCATED IN AN AREA OF LOW VERTICAL WIND SHEAR (VWS) WITH
FAVORABLE POLEWARD OUTFLOW. HOWEVER, AN UPPER LEVEL TROUGH IS
CAUSING SUBSIDENCE AND INCREASED VERTICAL WIND SHEAR TO THE WEST AND
MAY BE HINDERING EQUATORWARD OUTFLOW. SEA SURFACE TEMPERATURES (SST)
ARE FAVORABLE (>26 DEGREES CELSIUS). TC 18S IS CURRENTLY TRACKING
ALONG THE NORTHERN PERIPHERY OF A LOW- TO MID-LEVEL STEERING RIDGE
AND IS EXPECTED TO TRACK GENERALLY WEST-SOUTHWESTWARD TO
SOUTHWESTWARD THROUGHOUT THE FORECAST PERIOD. THE SYSTEM SHOULD
CONTINUE TO INTENSIFY AS IT TRACKS OVER FAVORABLE SSTS. HOWEVER, THE
TROUGH TO THE WEST COULD POTENTIALLY HINDER INTENSIFICATION MORE
THAN CURRENTLY FORECAST. AROUND TAU 72, VWS IS EXPECTED TO INCREASE
AND CAUSE TC 18S TO BEGIN TO WEAKEN. NUMERICAL MODEL GUIDANCE IS IN
GOOD AGREEMENT, ALTHOUGH ECMWF IS THE ONLY MODEL THAT CURVES THE
SYSTEM TO THE SOUTH IN RESPONSE TO A WEAKNESS IN THE STEERING RIDGE
IN THE LATER TAUS. THIS WARNING SUPERSEDES AND CANCELS REF A,
NAVMARFCSTCEN 162221Z MAR 11 TROPICAL CYCLONE FORMATION ALERT
=========================================================================
WTXS31 PGTW 20110317 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 18S (CHERONO) WARNING NR 002//
RMKS/
1. TROPICAL CYCLONE 18S (CHERONO) WARNING NR 002    
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   171800Z --- NEAR 15.8S 74.4E
     MOVEMENT PAST SIX HOURS - 240 DEGREES AT 10 KTS
     POSITION ACCURATE TO WITHIN 040 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 - 050 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   REPEAT POSIT: 15.8S 74.4E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   180600Z --- 16.1S 71.9E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
                            075 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            055 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 255 DEG/ 12 KTS
    ---
   24 HRS, VALID AT:
   181800Z --- 16.8S 69.5E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 015 NM NORTHEAST QUADRANT
                            015 NM SOUTHEAST QUADRANT
                            015 NM SOUTHWEST QUADRANT
                            015 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
                            085 NM SOUTHEAST QUADRANT
                            085 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 250 DEG/ 14 KTS
    ---
   36 HRS, VALID AT:
   190600Z --- 17.8S 66.7E
   MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            095 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 245 DEG/ 14 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   191800Z --- 18.9S 64.0E
   MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            025 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
                            100 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 235 DEG/ 12 KTS
    ---
   72 HRS, VALID AT:
   201800Z --- 21.5S 59.8E
   MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            095 NM SOUTHWEST QUADRANT
                            070 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 230 DEG/ 10 KTS
    ---
   LONG RANGE OUTLOOK:
   NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
   ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
   NEAR 20 KT EACH DAY.
    ---
   96 HRS, VALID AT:
   211800Z --- 24.1S 56.3E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 120 HR POSIT: 220 DEG/ 09 KTS
    ---
   120 HRS, VALID AT:
   221800Z --- 27.0S 53.7E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
REMARKS:
172100Z POSITION NEAR 15.9S 73.8E.
TROPICAL CYCLONE (TC) 18S (CHERONO), LOCATED APPROXIMATELY 515 NM 
SOUTH-SOUTHEAST OF DIEGO GARCIA, HAS TRACKED WEST-SOUTHWESTWARD AT 
10 KNOTS DURING THE PAST SIX HOURS. ANIMATED INFRARED (IR) SATELLITE 
IMAGERY SHOWS CONVECTIVE BANDING WRAPPING INTO A LOW LEVEL 
CIRCULATION CENTER. THE INITIAL POSITION IS BASED ON IR IMAGERY AND 
INTERPOLATED FROM A 171543Z SSMIS MICROWAVE IMAGE. THE INITIAL 
INTENSITY IS BASED ON PGTW AND KNES DVORAK ESTIMATES OF 40 KNOTS. 
UPPER LEVEL ANALYSIS INDICATES THE SYSTEM IS UNDER A POINT SOURCE 
WITH LOW VERTICAL WIND SHEAR (VWS) AND FAVORABLE RADIAL OUTFLOW. SEA 
SURFACE TEMPERATURES (SST) ARE FAVORABLE (>26 DEGREES CELSIUS). TC 
18S IS CURRENTLY TRACKING ALONG THE NORTHERN PERIPHERY OF A LOW-TO 
MID-LEVEL STEERING RIDGE AND IS EXPECTED TO TRACK GENERALLY WEST-
SOUTHWESTWARD DURING THE FIRST 48 HOURS. AS THE SYSTEM INTENSIFIES, 
THE PRIMARY STEERING MECHANISM WILL BECOME MORE MID-TO UPPER LEVEL 
AND RESULT IN A MORE SOUTHWESTERLY TRACK FOR 18S. AROUND TAU 72, VWS 
ASSOCIATED WITH AN UPPER LEVEL TROUGH WILL CAUSE TC 18S TO BEGIN 
WEAKENING. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH 
48HRS, HOWEVER ECMWF AND GFDN CURVE THE SYSTEM TO THE SOUTH IN 
RESPONSE TO A WEAKNESS IN THE STEERING RIDGE IN LATER TAUS. EGRR 
SOLUTIONS TREND MORE NORTHWARD, INDICATING POTENTIAL STRENGTHENING 
OF THE RIDGE NEAR MADAGASCAR AFTER TAU 48. PEAK INTENSITY HAS BEEN 
ADJUSTED TO 70 KNOTS FROM 55 KNOTS. MAXIMUM SIGNIFICANT WAVE HEIGHT 
AT 171800Z IS 14 FEET. NEXT WARNINGS AT 180900Z AND 182100Z.
=========================================================================
WTXS31 PGTW 20110318 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 18S (CHERONO) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 18S (CHERONO) WARNING NR 003    
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   180600Z --- NEAR 16.5S 72.4E
     MOVEMENT PAST SIX HOURS - 245 DEGREES AT 10 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            080 NM SOUTHWEST QUADRANT
                            070 NM NORTHWEST QUADRANT
   REPEAT POSIT: 16.5S 72.4E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   181800Z --- 17.5S 70.2E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
                            085 NM SOUTHEAST QUADRANT
                            085 NM SOUTHWEST QUADRANT
                            075 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 250 DEG/ 15 KTS
    ---
   24 HRS, VALID AT:
   190600Z --- 18.5S 67.3E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 025 NM NORTHEAST QUADRANT
                            025 NM SOUTHEAST QUADRANT
                            025 NM SOUTHWEST QUADRANT
                            025 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
                            090 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            080 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 250 DEG/ 15 KTS
    ---
   36 HRS, VALID AT:
   191800Z --- 19.6S 64.4E
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 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 - 085 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            095 NM SOUTHWEST QUADRANT
                            085 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 250 DEG/ 14 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   200600Z --- 20.6S 61.7E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            095 NM SOUTHWEST QUADRANT
                            085 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 240 DEG/ 12 KTS
    ---
   72 HRS, VALID AT:
   210600Z --- 22.8S 57.2E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 085 NM NORTHEAST QUADRANT
                            095 NM SOUTHEAST QUADRANT
                            095 NM SOUTHWEST QUADRANT
                            085 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 220 DEG/ 10 KTS
    ---
   LONG RANGE OUTLOOK:
   NOTE...ERRORS FOR TRACK HAVE AVERAGED NEAR 250 NM
   ON DAY 4 AND 350 NM ON DAY 5... AND FOR INTENSITY
   NEAR 20 KT EACH DAY.
    ---
   96 HRS, VALID AT:
   220600Z --- 25.7S 54.3E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   VECTOR TO 120 HR POSIT: 200 DEG/ 09 KTS
    ---
   120 HRS, VALID AT:
   230600Z --- 29.2S 52.8E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
180900Z POSITION NEAR 16.8S 71.8E.
TROPICAL CYCLONE (TC) 18S (CHERONO), LOCATED APPROXIMATELY 550 NM 
SOUTH OF DIEGO GARCIA, HAS TRACKED WEST-SOUTHWESTWARD AT 
10 KNOTS DURING THE PAST SIX HOURS. RECENT ANIMATED MULTISPECTRAL 
SATELLITE IMAGERY (MSI) SHOWS CONVECTIVE BANDING WRAPPING INTO A LOW 
LEVEL CIRCULATION CENTER (LLCC) AND A 180256Z SSMIS 37H GHZ 
MICROWAVE IMAGE DEPICTS THE MAJORITY OF THE LOW LEVEL CONVECTION 
ALONG THE SOUTHERN PERIPHERY. THIS ASYMMETRIC STRUCTURE COINCIDES 
WITH A RECENT 180450Z ASCAT PASS, WHICH INDICATES WEAK 15- TO 20-
KNOT WINDS ALONG THE NORTHERN PERIPHERY OF THE LLCC AND STRONGER 
FLOW WRAPPING AROUND THE EASTERN TO SOUTHERN PERIPHERY. THE ASCAT 
ALSO DEPICTS STRONG 30-KNOT GRADIENT FLOW TO THE SOUTH. TC 18S HAS 
INTENSIFIED SLIGHTLY WITHIN THE PAST 12 HOURS AND HAS LIKELY BEEN 
SLOW TO DEVELOP DUE TO THE ASYMMETRIC STRUCTURE AND DRY AIR WRAPPING 
INTO THE SYSTEM EVIDENT IN THE CIMSS TOTAL PRECIPITABLE WATER 
PRODUCT. THE INITIAL POSITION IS BASED ON THE MSI AND INTERPOLATED 
FROM THE SSMIS IMAGE. THE INITIAL INTENSITY IS BASED ON PGTW, KNES, 
AND FMEE DVORAK ESTIMATES OF 45 KNOTS. UPPER LEVEL ANALYSIS 
INDICATES THE SYSTEM IS LOCATED BENEATH A SUBTROPICAL RIDGE AXIS IN 
AN AREA OF LOW VERTICAL WIND SHEAR AND GOOD DIVERGENCE ALOFT. 
ADDITIONALLY, POLEWARD OUTFLOW REMAINS STRONG. TC CHERONO IS 
CURRENTLY TRACKING ALONG THE NORTHWESTERN PERIPHERY OF A LOW- TO MID-
LEVEL STEERING RIDGE AND IS FORECAST TO CONTINUE TRACKING WEST-
SOUTHWESTWARD UNTIL TAU 72. AT THAT TIME, AN UPPER LEVEL, MID-
LATITUDE TROUGH IS EXPECTED TO WEAKEN THE STEERING RIDGE AND ALLOW 
THE SYSTEM TO TURN SOUTHWESTWARD. TC 18S SHOULD CONTINUE 
INTENSIFYING UNDER A FAVORABLE UPPER LEVEL ENVIRONMENT AND WARM SEA 
SURFACE TEMPERATURES (>26 DEGREES CELSIUS). AFTER TAU 36, IT WILL 
BEGIN TO ENCOUNTER HIGHER VERTICAL WIND SHEAR ASSOCIATED WITH AN 
UPPER LEVEL TROUGH, AND BEGIN WEAKENING. NUMERICAL MODEL GUIDANCE IS 
IN EXCELLENT AGREEMENT UNTIL TAU 48, WHEN THE MODELS BEGIN TO 
DIVERGE IN THE TIMING OF THE TURN POLEWARD. ECMWF QUICKLY TURNS THE 
SYSTEM POLEWARD, WHILE NOGAPS, UKMO, AND GFDN CONTINUE TRACKING IT 
FARTHER TO THE WEST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 180600Z IS 
17 FEET. NEXT WARNINGS AT 182100Z AND 190900Z.//
=========================================================================
WTXS31 PGTW 20110318 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 18S (CHERONO) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 18S (CHERONO) WARNING NR 004
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   181800Z --- NEAR 17.3S 69.8E
     MOVEMENT PAST SIX HOURS - 250 DEGREES AT 12 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 - 065 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   REPEAT POSIT: 17.3S 69.8E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   190600Z --- 18.1S 67.2E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            075 NM SOUTHWEST QUADRANT
                            065 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 245 DEG/ 14 KTS
    ---
   24 HRS, VALID AT:
   191800Z --- 19.2S 64.4E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 36 HR POSIT: 250 DEG/ 14 KTS
    ---
   36 HRS, VALID AT:
   200600Z --- 20.1S 61.6E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 48 HR POSIT: 255 DEG/ 14 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   201800Z --- 20.8S 58.8E
   MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
182100Z POSITION NEAR 17.5S 69.1E.
TROPICAL CYCLONE (TC) 18S (CHERONO), LOCATED APPROXIMATELY 825 NM
EAST-NORTHEAST OF LA REUNION, HAS TRACKED WEST-SOUTHWESTWARD AT
12 KNOTS OVER THE PAST SIX HOURS. ANIMATED WATER VAPOR IMAGERY SHOWS
INCREASED CONVECTION OVER TC 18S AS POLEWARD OUTFLOW GREATLY IMPROVED
AS THE SYSTEM TRACKED DIRECTLY UNDER THE UPPER LEVEL RIDGE AXIS.
HOWEVER, THE WESTERN SIDE OF THE CYCLONE APPEARS TO BE ERODING AS A
WEAK TROUGH JUST TO THE SOUTHWEST IS CREATING CONVERGENCE WITH THE
BACK SIDE OF THE RIDGE. THIS, COUPLED WITH DRY-AIR ENTRAINMENT,
EVIDENT ON THE CIMSS TOTAL PRECIPITABLE WATER PRODUCT HAS RESTRAINED
THE CYCLONE FROM FURTHER DEVELOPMENT. THE INITIAL POSITION IS BASED
ON ANIMATED INFRARED SATELLITE IMAGERY WITH POOR CONFIDENCE. THE
INITIAL INTENSITY IS BASED ON DVORAK ESTIMATES RANGING FROM T2.5 TO
T3.0 FROM PGTW, KNES, AND FMEE. TC CHERONO IS EXPECTED TO CONTINUE TO
WEAKEN AS IT TRACKS FURTHER WEST-SOUTHWESTWARD ALONG THE PERIPHERY OF
A SUBTROPICAL RIDGE TO THE SOUTHEAST INTO AN AREA OF INCREASING
VERTICAL WIND SHEAR, DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE
OVER WATER IN 48 HOURS. THE AVAILABLE NUMERICAL GUIDANCE IS IN SOLID
AGREEMENT WITH THIS TRACK FORECAST. MAXIMUM SIGNIFICANT WAVE HEIGHT
AT 181800Z IS 15 FEET. NEXT WARNINGS AT 190900Z AND 192100Z.//
=========================================================================
WTXS31 PGTW 20110319 09:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 18S (CHERONO) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 18S (CHERONO) 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:
   190600Z --- NEAR 19.0S 67.7E
     MOVEMENT PAST SIX HOURS - 245 DEGREES AT 12 KTS
     POSITION ACCURATE TO WITHIN 040 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   REPEAT POSIT: 19.0S 67.7E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   191800Z --- 20.1S 65.0E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 250 DEG/ 15 KTS
    ---
   24 HRS, VALID AT:
   200600Z --- 21.0S 62.0E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
                            065 NM SOUTHEAST QUADRANT
                            065 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 245 DEG/ 14 KTS
    ---
   36 HRS, VALID AT:
   201800Z --- 22.1S 59.3E
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   VECTOR TO 48 HR POSIT: 235 DEG/ 13 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   210600Z --- 23.5S 56.9E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
190900Z POSITION NEAR 19.3S 67.0E.
TROPICAL CYCLONE (TC) 18S (CHERONO), LOCATED APPROXIMATELY 695 NM
EAST OF LA REUNION, HAS TRACKED WEST-SOUTHWESTWARD AT 12 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY
INDICATES CONTINUED WEAKENING OF DEEP CONVECTION OVER THE PAST 06
HOURS WITH THE BULK OF THE DEEP CONVECTION CONFINED TO THE SOUTHERN
SEMI-CIRCLE. CONSEQUENTLY, DVORAK ESTIMATES FROM PGTW, KNES AND FMEE
HAVE DECREASED TO 35 KNOTS. THE CURRENT INTENSITY, HOWEVER, IS
ASSESSED HIGHER AT 45 KNOTS BASED ON A 19/0431Z ASCAT PARTIAL IMAGE,
WHICH INDICATES NUMEROUS 40-KNOT VECTORS OVER THE SOUTHWEST QUADRANT,
AND A 19/0156Z TRMM 37V IMAGE DEPICTING A WELL-ORGANIZED LOW-LEVEL
CIRCULATION CENTER (LLCC) WITH A MICROWAVE EYE FEATURE. RECENT
AUTOMATED INTENSITY ESTIMATES HAVE RANGED FROM 45 TO 55 KNOTS.
DESPITE THE IMPROVED LOW-LEVEL SIGNATURE, TC 18S CONTINUES TO
STRUGGLE DUE TO INCREASING VERTICAL WIND SHEAR AND DRY AIR
ENTRAINMENT EVIDENT ON TOTAL PRECIPITABLE WATER PRODUCTS, AND LACKS
SIGNIFICANT DEEP CONVECTIVE BANDING. TC 18S IS TRACKING ALONG THE
NORTHWESTERN PERIPHERY OF THE LOW- TO MID-LEVEL SUBTROPICAL RIDGE
AND IS EXPECTED TO CONTINUE TRACKING WEST-SOUTHWESTWARD THROUGH TAU
36 BUT SHOULD TURN SOUTHWESTWARD AHEAD OF AN APPROACHING MID-
LATITUDE SHORTWAVE TROUGH, WHICH WILL PRODUCE INCREASING VERTICAL
WIND SHEAR AND WILL FURTHER WEAKEN THE SYSTEM. MODEL GUIDANCE IS IN
FAIR AGREEMENT BUT DIVERGES NEAR THE RE-CURVE POINT DUE TO MINOR
DIFFERENCES IN THE STRENGTH OF THE SHORTWAVE TROUGH. THIS FORECAST
IS POSITIONED CLOSE TO BUT JUST SOUTH OF THE MODEL CONSENSUS AND
INDICATES DISSIPATION NEAR TAU 48. MAXIMUM SIGNIFICANT WAVE HEIGHT AT
190600Z IS 14 FEET. NEXT WARNINGS AT 192100Z AND 200900Z.//
=========================================================================
WTXS31 PGTW 20110319 21:00z
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 18S (CHERONO) WARNING NR 006//
RMKS/
1. TROPICAL CYCLONE 18S (CHERONO) WARNING NR 006
   01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   191800Z --- NEAR 19.7S 65.0E
     MOVEMENT PAST SIX HOURS - 255 DEGREES AT 08 KTS
     POSITION ACCURATE TO WITHIN 060 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
   DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
   REPEAT POSIT: 19.7S 65.0E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   200600Z --- 20.8S 62.2E
   MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER
    ---
REMARKS:
192100Z POSITION NEAR 20.0S 64.3E.
TROPICAL CYCLONE (TC) 18S (CHERONO), LOCATED APPROXIMATELY 595 NM
EAST OF LA REUNION, HAS TRACKED WEST-SOUTHWESTWARD AT 08 KNOTS OVER
THE PAST SIX HOURS. ANIMATED WATER VAPOR SATELLITE IMAGERY SHOWS THE
CONVECTION ASSOCIATED WITH THE SYSTEM HAS SIGNIFICANTLY REDUCED AND
SHALLOWED. THIS IS CONFIRMED BY A 191446Z SSMIS MICROWAVE IMAGE
DEPICTING A LOW LEVEL CIRCULATION CENTER FULLY DETACHED FROM MARGINAL
CONVECTION TO THE SOUTHEAST. THE INITIAL POSITION IS BASED ON
ANIMATED INFRARED IMAGERY AND FROM THE SSMIS IMAGE. THE INITIAL
INTENSITY IS EXTRAPOLATED FROM RECENT ASCAT IMAGERY SHOWING 20-30
KNOT WIND BARBS AROUND THE PERIPHERY OF THE SYSTEM. UPPER LEVEL
ANALYSIS INDICATES THE SYSTEM IS NOW JUST TO THE SOUTH OF THE RIDGE
AXIS IN AN AREA OF MODERATE (25-30 KT) NORTHWESTERLY VERTICAL WIND
SHEAR. TC CHERONO IS EXPECTED TO CONTINUE BE STEERED BY THE
SUBTROPICAL RIDGE TO THE SOUTHEAST AND TRACKING WEST- SOUTHWESTWARD,
BEFORE DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER BY
TAU 48. THE AVAILABLE NUMERICAL GUIDANCE IS IN SOLID AGREEMENT WITH
THIS TRACK FORECAST. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE
JOINT TYPHOON WARNING CENTER (NAVMARFCSTCEN).  THE SYSTEM WILL BE
CLOSELY MONITORED FOR SIGNS OF REGENERATION. MAXIMUM SIGNIFICANT WAVE
HEIGHT AT 191800Z IS 12 FEET.//

Tropical cyclone tracks developed by Michael Bath using operational warnings and advisories.


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Document: tropical_cyclone_cherono_jtwc_advisories.htm Updated: 2 May 2017