Southern Hemisphere cyclonic activity: 02/03utc updates


JTWC IS ISSUING 6HOURLY WARNINGS ON 17P(LUCAS) AND 18S. WARNING 12/FINAL WAS ISSUED AT 01/21UTC FOR 15P(ANA). 3 HOURLY SATELLITE BULLETINS ARE PROVIDED 15P,17P AND 18S.


JTWC IS ISSUING 6HOURLY WARNINGS ON 17P(LUCAS) AND 18S. WARNING 12/FINAL WAS ISSUED AT 01/21UTC FOR 15P(ANA). 3 HOURLY SATELLITE BULLETINS ARE PROVIDED 15P,17P AND 18S.
JTWC IS ISSUING 6HOURLY WARNINGS ON 17P(LUCAS) AND 18S. WARNING 12/FINAL WAS ISSUED AT 01/21UTC FOR 15P(ANA). 3 HOURLY SATELLITE BULLETINS ARE PROVIDED 15P,17P AND 18S.
2021 FEB 02 0155UTC #SOUTHERNHEMISPHERE
TC #15P #ANA #SOUTHPACIFICOCEAN
WARNING 12/UPDATE
As of 00:00 UTC Feb 02, 2021:
Location: 23.8°S 178.0°W
Maximum Winds: 35 kt (65km/h)
Minimum Central Pressure: 987 mb
SUBTROPICAL
15P (ANA), LOCATED APPROXIMATELY 410 KM SOUTHWEST OF TONGA,  HAS TRACKED EAST-SOUTHEASTWARD AT
43 KM/H OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
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TC #17P #LUCAS  #SOUTHPACIFICOCEAN
WARNING 9
As of 00:00 UTC Feb 02, 2021:
Location: 17.1°S 165.0°E
Maximum Winds: 45 kt (85km/h)
Gusts: 55kt (100km/h)
Minimum Central Pressure: 990 mb
17P(LUCAS), LOCATED APPROXIMATELY 565 KM NORTH-NORTHWEST OF NOUMEA, NEW CALEDONIA, HAS TRACKED EAST-
SOUTHEASTWARD AT 20 KM/H OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS

----------------------------------------------------------------------------------------------------------------
TC #18S  #SOUTHINDIANOCEAN
WARNING 7
As of 00:00 UTC Feb 02, 2021:
Location: 22.1°S 116.2°E
Maximum Winds: 30 kt (55km/h)
Gusts: 40 kt (75km/h)
Minimum Central Pressure: 996 mb
18S (EIGHTEEN), LOCATED APPROXIMATELY 215 KNM EAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWESTWARD AT
19 KM/H OVER THE PAST SIX HOURS.

Satellite bulletins are to be found in the comments of this post on JTWC BIS
-----------------------------------------------------------------------------------------------------------------------
REMNANTS #13S  #SOUTHINDIANOCEAN
UPDATE
As of 00:00 UTC Feb 02, 2021:
Location: 13.0°S 55.2°E
Maximum Winds: 20 kt
Minimum Central Pressure: 1006 mb

Cheers,
Patrick Hoareau
 Météo974
M974World
Cyclone Class 4
 Cheers,PH.

Joint Typhoon Warning Center

15P(ANA). WARNING 12/FINAL ISSUED AT 01/21UTC. PEAK INTENSITY WAS 65KNOTS: US/CATEGORY 1.
15P(ANA). WARNING 12/FINAL ISSUED AT 01/21UTC. PEAK INTENSITY WAS 65KNOTS: US/CATEGORY 1.
JMV FILE
1521012618 162S1684E  20
1521012700 162S1686E  25
1521012706 161S1688E  25
1521012712 161S1691E  25
1521012718 160S1693E  25
1521012800 156S1695E  25
1521012806 156S1701E  25
1521012812 157S1711E  25
1521012818 157S1717E  25
1521012900 157S1724E  30
1521012906 156S1732E  30
1521012912 153S1745E  30
1521012918 157S1757E  35
1521013000 161S1765E  40
1521013006 165S1770E  45
1521013012 169S1775E  50
1521013018 174S1780E  60
1521013100 181S1782E  65
1521013106 188S1781E  60
1521013112 196S1786E  55
1521013118 204S1788E  55
1521020100 211S1790E  55
1521020106 219S1792E  50
1521020112 224S1793E  45
1521020118 231S1796E  40
NNNN
 

17P(LUCAS). WARNING 9. THE INITIAL POSITION IS PLACED  WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLC IN THE EIR LOOP. THE  INITIAL INTENSITY OF 45KTS IS EXTRAPOLATED FROM 012038UTC ASCAT PARTIAL  PASS NEAR THE CENTER AND SUPPORTED BY A 020040Z ADT ESTIMATE OF 47KTS.  UPPER-LEVEL ANALYSIS INDICATES STRONG (35KNOTS+) VERTICAL WIND SHEAR  PARTLY OFFSET BY ROBUST POLEWARD OUTFLOW. TC 17P IS FORECAST TO  TRACK SOUTHEASTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A NEAR- EQUATORIAL RIDGE THROUGH 24H. AFTERWARD. THE SUBTROPICAL RIDGE TO  THE SOUTHEAST WILL ASSUME STEERING AND DRIVE THE SYSTEM SOUTHWARD THEN  SOUTHWESTWARD, PASSING JUST OFF THE SOUTHERN TIP OF NEW CALEDONIA  AROUND 48H. TC LUCAS IS EXPECTED TO GRADUALLY WEAKEN AS THE WIND SHEAR  FURTHER INCREASES AND SST VALUES COOL TO 25C, LEADING TO INTENSITY FALLING DOWN BELOW 35KNOTS BY 72H, POSSIBLY SOONER.
17P(LUCAS). WARNING 9. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLC IN THE EIR LOOP. THE INITIAL INTENSITY OF 45KTS IS EXTRAPOLATED FROM 012038UTC ASCAT PARTIAL PASS NEAR THE CENTER AND SUPPORTED BY A 020040Z ADT ESTIMATE OF 47KTS. UPPER-LEVEL ANALYSIS INDICATES STRONG (35KNOTS+) VERTICAL WIND SHEAR PARTLY OFFSET BY ROBUST POLEWARD OUTFLOW. TC 17P IS FORECAST TO TRACK SOUTHEASTWARD ALONG THE SOUTHWESTERN PERIPHERY OF A NEAR- EQUATORIAL RIDGE THROUGH 24H. AFTERWARD. THE SUBTROPICAL RIDGE TO THE SOUTHEAST WILL ASSUME STEERING AND DRIVE THE SYSTEM SOUTHWARD THEN SOUTHWESTWARD, PASSING JUST OFF THE SOUTHERN TIP OF NEW CALEDONIA AROUND 48H. TC LUCAS IS EXPECTED TO GRADUALLY WEAKEN AS THE WIND SHEAR FURTHER INCREASES AND SST VALUES COOL TO 25C, LEADING TO INTENSITY FALLING DOWN BELOW 35KNOTS BY 72H, POSSIBLY SOONER.


17P(LUCAS). NUMERICAL MODELS ARE IN GOOD AGREEMENT  LEADING TO AN OVERALL FAIR CONFIDENCE IN THE JTWC TRACK FORECAST.
17P(LUCAS). NUMERICAL MODELS ARE IN GOOD AGREEMENT LEADING TO AN OVERALL FAIR CONFIDENCE IN THE JTWC TRACK FORECAST.


17P(LUCAS). 01/2153UTC. ASCAT READ 45KNOT WINDS.
17P(LUCAS). 01/2153UTC. ASCAT READ 45KNOT WINDS.


18S. WARNING 7. THE INITIAL  POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A LOW LEVEL  CIRCULATION (LLC) FEATURE EVIDENT ON AN ABOM COMPOSITE RADAR LOOP THAT  ALSO SHOWED ORGANIZED RAIN BANDS WRAPPING INTO THE WELL-DEFINED LLCC.  THE INITIAL INTENSITY OF 30 KNOTS IS BASED ON THE SUSTAINED CONVECTIVE  STRUCTURE AND EXTRAPOLATED FROM MULTIPLE SURFACE OBSERVATIONS ALONG  THE COAST.18S WILL CONTINUE ON ITS CURRENT  TRACK THROUGH 24H UNDER THE STEERING INFLUENCE OF A LOW- TO MID- LEVEL SUBTROPICAL RIDGE (STR) TO THE SOUTH, PASSING APPROXIMATELY 100KM  SOUTH OF LEARMONTH AROUND 021400UTC. AFTERWARD, AS 18S EXITS INTO THE  INDIAN OCEAN, THE STORM MOTION WILL BECOME QUASI-STATIONARY (QS) AS A  SECONDARY STR BUILDING TO THE SOUTHWEST COMPETES FOR STEERING,  RESULTING IN A VERY SLOW WESTWARD TRACK TO 48H. AFTER 48H, THE  SECONDARY STR WEAKENS, ALLOWING THE PRIMARY STR TO RESUME STEERING AND  DRIVE THE TC SOUTHWESTWARD THEN SOUTHWARD. TC 18S IS EXPECTED TO  MAINTAIN INTENSITY WHILE IT TRACKS OVER LAND BUT WILL INTENSIFY TO 35  KNOTS AFTER IT EXITS INTO THE WARM (28C) INDIAN OCEAN. THE WARM SST  PLUS LOW WIND SHEAR WILL PROMOTE STEADY INTENSIFICATION TO A PEAK OF 50 KNOTS  BY 72H. AFTERWARD, COOLING SST AND INCREASING VWS WILL GRADUALLY  ERODE THE SYSTEM DOWN TO 40KNOTS BY 120H.
18S. WARNING 7. THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON A LOW LEVEL CIRCULATION (LLC) FEATURE EVIDENT ON AN ABOM COMPOSITE RADAR LOOP THAT ALSO SHOWED ORGANIZED RAIN BANDS WRAPPING INTO THE WELL-DEFINED LLCC. THE INITIAL INTENSITY OF 30 KNOTS IS BASED ON THE SUSTAINED CONVECTIVE STRUCTURE AND EXTRAPOLATED FROM MULTIPLE SURFACE OBSERVATIONS ALONG THE COAST.18S WILL CONTINUE ON ITS CURRENT TRACK THROUGH 24H UNDER THE STEERING INFLUENCE OF A LOW- TO MID- LEVEL SUBTROPICAL RIDGE (STR) TO THE SOUTH, PASSING APPROXIMATELY 100KM SOUTH OF LEARMONTH AROUND 021400UTC. AFTERWARD, AS 18S EXITS INTO THE INDIAN OCEAN, THE STORM MOTION WILL BECOME QUASI-STATIONARY (QS) AS A SECONDARY STR BUILDING TO THE SOUTHWEST COMPETES FOR STEERING, RESULTING IN A VERY SLOW WESTWARD TRACK TO 48H. AFTER 48H, THE SECONDARY STR WEAKENS, ALLOWING THE PRIMARY STR TO RESUME STEERING AND DRIVE THE TC SOUTHWESTWARD THEN SOUTHWARD. TC 18S IS EXPECTED TO MAINTAIN INTENSITY WHILE IT TRACKS OVER LAND BUT WILL INTENSIFY TO 35 KNOTS AFTER IT EXITS INTO THE WARM (28C) INDIAN OCEAN. THE WARM SST PLUS LOW WIND SHEAR WILL PROMOTE STEADY INTENSIFICATION TO A PEAK OF 50 KNOTS BY 72H. AFTERWARD, COOLING SST AND INCREASING VWS WILL GRADUALLY ERODE THE SYSTEM DOWN TO 40KNOTS BY 120H.

18S. NUMERICAL MODELS ARE IN  FAIRLY GOOD AGREEMENT WITH SPREADING TO OVER 425KM BY 120H. THIS,  PLUS THE UNCERTAINTY IN THE QUASI STATIONARY MOTION IN THE MID-PORTION, LENDS AN  OVERALL LOW CONFIDENCE TO THE JTWC TRACK FORECAST.
18S. NUMERICAL MODELS ARE IN FAIRLY GOOD AGREEMENT WITH SPREADING TO OVER 425KM BY 120H. THIS, PLUS THE UNCERTAINTY IN THE QUASI STATIONARY MOTION IN THE MID-PORTION, LENDS AN OVERALL LOW CONFIDENCE TO THE JTWC TRACK FORECAST.

18S. 02/0150UTC. A 12-HR ANIMATED MULTISPECTRAL  SATELLITE IMAGERY SHOWS THE SYSTEM MAINTAINED ITS DEEP CONVECTIVE  STRUCTURE AS IT TRACKED OVER LAND TOWARD LEARMONTH/WESTERN AUSTRALIA.
18S. 02/0150UTC. A 12-HR ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM MAINTAINED ITS DEEP CONVECTIVE STRUCTURE AS IT TRACKED OVER LAND TOWARD LEARMONTH/WESTERN AUSTRALIA.

REMNANTS 13S. 01/2356UTC. THE LOW LEVEL CIRCULATION IS STILL IDENTIFIED BUT HAS BEEN ALMOST COMPLETELY DEVOID OF DEEP CONVECTION.
REMNANTS 13S. 01/2356UTC. THE LOW LEVEL CIRCULATION IS STILL IDENTIFIED BUT HAS BEEN ALMOST COMPLETELY DEVOID OF DEEP CONVECTION.

Rédigé par PATRICK HOAREAU le Mardi 2 Février 2021 à 07:00