SPO : EX-TROPICAL CYCLONE NISHA 06F (10P)

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28/2022 UTC 19.7S 164.1W T3.5/3.5 NISHA -- Southeast Pacific

55 knots

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TROPICAL DISTURBANCE ADVISORY NUMBER A8 ISSUED FROM RSMC NADI
Jan 28/2032 UTC 2010 UTC.

TROPICAL CYCLONE NISHA 06F [990HPA] CENTRE NEAR 29.1S 164.6W AT
281800 UTC MOVING SOUTHEAST AT 14 KNOTS. POSITION POOR BASED ON MTSAT
EIR IMAGERY WITH ANIMATION. 10-MINUTE AVERAGE SUSTAINED WINDS
ESTIMATED AT 40 KNOTS CLOSE TO THE CENTRE. EXPECT WINDS OVER 33 KNOTS
WITHIN 120 NAUTICAL MILES OF CENTRE IN THE SECTORS FROM NORTHEAST
THROUGH SOUTHEAST TO SOUTHWEST AND WITHIN 60 MILES OF CENTRE
ELSEWHERE.

INCREASING VERTICAL SHEAR EVIDENT WITH LOW-LEVEL CLOUD LINES EXPOSED
TO NORTHWEST OF DEEP CONVECTION AND OVERALL ORGANISATION LOSING
STRUCTURE. CYCLONE STEERED BY DEEP LAYER MEAN NORTHWEST FLOW. TURN
TOWARDS EAST WILL TAKE THE CYCLONE INTO STRONGER SHEAR. DVORAK BASED
0.6 WRAP ON LOG 10 SPIRAL YIELDING A DT=3.0, PT=2.5, MET=3.0. FT
BASED ON PT, THUS T2.5/3.0/W0.5/24HRS.
MOST GLOBAL MODELS GENERALLY AGREE ON AN EASTERLY TRACK WITH GRADUAL
WEAKENING.

FORECAST:
AT 12 HRS VALID AT 29060UTC NEAR 20.7S 163.1W MOVING ESE 7 KNOTS WITH
40 KNOTS CLOSE TO CENTRE.
AT 24 HRS VALID AT 291800UTC NEAR 20.8S 161.8W MOVING E 6 KNOTS WITH
35 KNOTS CLOSE TO CENTRE.

OUTLOOK:
AT 36 HRS VALID AT 300600UTC NEAR 20.7S 160.5W MOVING E 7 KNOTS WITH
35 KNOTS CLOSE TO CENTRE.
AT 48 HRS VALID AT 301800UTC NEAR 20.4S 159.0W MOVING ENE 7 KNOTS
WITH 30 KNOTS CLOSE TO CENTRE.

THE NEXT TROPICAL DISTURBANCE ADVISORY ON TC NISHA WILL BE ISSUED
AROUND 290230 UTC OR EARLIER.

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Latest

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TROPICAL DISTURBANCE ADVISORY NUMBER A9 ISSUED FROM RSMC NADI
Jan 29/0137 UTC 2010 UTC.

TROPICAL CYCLONE NISHA 06F [990HPA] CENTRE NEAR 20.1S 164.0W AT
290000 UTC MOVING east-SOUTHEAST AT 11 KNOTS. POSITION POOR BASED ON
MTSAT EIR/VIS IMAGERY WITH ANIMATION. 10-MINUTE AVERAGE SUSTAINED
WINDS ESTIMATED AT 40 KNOTS CLOSE TO THE CENTRE. EXPECT WINDS OVER 33
KNOTS WITHIN 120 NAUTICAL MILES OF CENTRE IN THE SECTORS FROM
NORTHEAST THROUGH SOUTHEAST TO SOUTHWEST AND WITHIN 60 MILES OF
CENTRE ELSEWHERE.

SHEAR STILL EVIDENT TO WEST AND NORTH. PRIMARY BAND TO EAST IS BEING
STEADILY TORN AWAY. HOWEVER, DEEP CONVECTION PERSISTING OVER LLCC.
OUTFLOW GOOD TO SOUTH AND EAST BUT RESTRICTED ELSEWHERE. CYCLONE
LYING UNDER STRONGLY DIFFLUENT REGION. SYSTEM STEERED BY DEEP LAYER
MEAN NORTHWEST FLOW. TURN TOWARDS EAST WILL TAKE THE CYCLONE INTO
STRONGER SHEAR. DVORAK BASED 0.6 WRAP ON LOG 10 SPIRAL YIELDING A
DT=3.0, PT=3.0, MET=3.0. FT BASED ON PT, THUS T3.0/3.0/S0.0/24HRS.
MOST GLOBAL MODELS GENERALLY AGREE ON AN EASTERLY TRACK WITH GRADUAL
WEAKENING.

FORECAST:
AT 12 HRS VALID AT 29120UTC NEAR 20.5S 162.8W MOVING ESE 6 KNOTS WITH
40 KNOTS CLOSE TO CENTRE.
AT 24 HRS VALID AT 300000UTC NEAR 20.6S 161.6W MOVING E 6 KNOTS WITH
35 KNOTS CLOSE TO CENTRE.

OUTLOOK:
AT 36 HRS VALID AT 301200UTC NEAR 20.3S 160.4W MOVING E 6 KNOTS WITH
30 KNOTS CLOSE TO CENTRE.
AT 48 HRS VALID AT 310000UTC NEAR 19.9S 159.2W MOVING ENE 6 KNOTS
WITH 30 KNOTS CLOSE TO CENTRE.

THE NEXT TROPICAL DISTURBANCE ADVISORY ON TC NISHA WILL BE ISSUED
AROUND 290830 UTC OR EARLIER.

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WTPS32 PGTW 290300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 10P (NISHA) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 10P (NISHA) WARNING NR 004
01 ACTIVE TROPICAL CYCLONE IN SOUTHPAC
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
WIND RADII VALID OVER OPEN WATER ONLY
---
WARNING POSITION:
290000Z --- NEAR 20.4S 163.8W
MOVEMENT PAST SIX HOURS - 130 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 - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
REPEAT POSIT: 20.4S 163.8W
---
FORECASTS:
12 HRS, VALID AT:
291200Z --- 21.2S 161.8W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
050 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 080 DEG/ 10 KTS
---
24 HRS, VALID AT:
300000Z --- 20.9S 159.6W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
065 NM SOUTHWEST QUADRANT
070 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 080 DEG/ 09 KTS
---
36 HRS, VALID AT:
301200Z --- 20.6S 157.7W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 075 DEG/ 09 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
310000Z --- 20.1S 155.8W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 085 DEG/ 05 KTS
---
72 HRS, VALID AT:
010000Z --- 19.9S 153.5W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 075 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
075 NM NORTHWEST QUADRANT
VECTOR TO 96 HR POSIT: 105 DEG/ 05 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:
020000Z --- 20.5S 151.3W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
VECTOR TO 120 HR POSIT: 115 DEG/ 05 KTS
---
120 HRS, VALID AT:
030000Z --- 21.4S 149.3W
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
---
REMARKS:
290300Z POSITION NEAR 20.6S 163.3W.
TROPICAL CYCLONE (TC) 10P (NISHA), LOCATED APPROXIMATELY 235 NM WEST-
NORTHWEST OF RAROTONGA, HAS TRACKED SOUTHEASTWARD AT 10 KNOTS OVER
THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS
DEEP CONVECTION HAS PERSISTED OVER THE PAST 12 HOURS OVER THE LOW
LEVEL CIRCULATION CENTER (LLCC) AND IS BEING IMPACTED ALONG THE
WESTERN EDGE BY UPPER LEVEL WESTERLIES AROUND AN UPPER LEVEL NEAR
EQUATORIAL RIDGE (NER) CREATING MODERATE TO HIGH VERTICAL WIND SHEAR
(VWS). OUTFLOW FROM TC 10P WILL BE MAINTAINED BY THE GOOD WESTERLY
FLOW AROUND THE NER, ALLOWING TC 10P TO PERSIST AS A 45 KNOT SYSTEM
THROUGH THE FORECAST PERIOD. THE OVERALL ENVIRONMENT IS NOT EXPECTED
TO CHANGE SIGNIFICANTLY OVER THE NEXT FIVE DAYS AS THE NER IS FORE-
CAST TO REMAIN IN PLACE, CREATING A SIMILAR VWS AND OUTFLOW PATTERN.
THE SURFACE ENVIRONMENT WILL ALSO REMAIN CONSISTENT WITH NEAR EQUA-
TORIAL WESTERLIES WRAPPING INTO THE LLCC FROM THE NORTH, AND EASTERLY
FLOW AROUND A SURFACE SUBTROPICAL RIDGE (STR) WRAPPING INTO THE LLCC
FROM THE SOUTH. SEA SURFACE TEMPERATURES ARE EXPECTED TO REMAIN
FAVORABLE (BETWEEN 26 AND 28 CELSIUS) THROUGH TAU 120. THE TRACK WILL
REMAIN STEADY THROUGH TAU 72 ALONG THE SOUTHERN EDGE OF THE MID-LEVEL
NER, TRACKING TO THE EAST, BUT WILL SLOW AFTER TAU 72 AS AN EXTENSION
OF THE STR BEGINS TO INFLUENCE THE TRACK, CAUSING A MORE SOUTH-
EASTWARD TURN. THIS WILL LEAD TO A DECREASE IN TRACK SPEED BEYOND
TAU 72 AS TC 10P TRANSITIONS TO THE STR. MODEL GUIDANCE IS IN FAIR
AGREEMENT WITH THE INITIAL 72 HOURS OF THE FORECAST, BUT DIVERGE
SIGNIFICANTLY BEYOND, WITH THE FORECAST BASED PREDOMINANTLY ON
PERSISTENCE. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 290000Z IS 20 FEET.
NEXT WARNINGS AT 291500Z AND 300300Z.//
NNNN

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Latest

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TROPICAL DISTURBANCE ADVISORY NUMBER A11 ISSUED FROM RSMC NADI
Jan 29/1308 UTC 2010 UTC.

TROPICAL DEPRESSION 06F [EX-TC NISHA] [997HPA] CENTRE NEAR 20.3S
160.9W AT 291200 UTC MOVING EAST AT 15 KNOTS. POSITION FAIR BASED ON
MTSAT EIR IMAGERY WITH ANIMATION.

LLCC EXPSOED WITH DEEP CONVECTION SHEARED TO THE EAST. SYSTEM
CONTINUES TO BE STEERED BY DEEP LAYER MEAN WESTERLY FLOW. DVORAK
BASED ON SHEAR PATTERN WITH LLCC GREATER THAN 0.75 DEGL FROM DG
YIELDING A DT=2.5, PT=2.0, MET=2.0. FT BASED ON DT, THUS
T2.5/3.0/W0.5/6HRS.
MOST GLOBAL MODELS GENERALLY AGREE ON AN EASTERLY TRACK WITH FURTHER
WEAKENING.


THIS WILL BE THE LAST TROPICAL DISTURBANCE ADVISORY ON EX-TC NISHA.