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Southern Hemisphere: hectic situation! JTWC issuing warnings on 4 systems! 31/15utc updates


JTWC IS ISSUING 6HOURLY WARNINGS ON 15P(ANA), 16P, 17P(LUCAS), 18S. 3 HOURLY SATELLITE BULLETINS ARE PROVIDED FOR THE 4 CYCLONIC SYSTEMS.


JTWC IS ISSUING 6HOURLY WARNINGS ON 15P(ANA), 16P, 17P(LUCAS), 18S. 3 HOURLY SATELLITE BULLETINS ARE PROVIDED FOR THE 4 CYCLONIC SYSTEMS.
JTWC IS ISSUING 6HOURLY WARNINGS ON 15P(ANA), 16P, 17P(LUCAS), 18S. 3 HOURLY SATELLITE BULLETINS ARE PROVIDED FOR THE 4 CYCLONIC SYSTEMS.
2021 JAN 31 1450UTC #SOUTHERNHEMISPHERE
TC #15P #ANA #SOUTHPACIFICOCEAN
WARNING 7
As of 12:00 UTC Jan 31, 2021:
Location: 19.6°S 178.6°E
Maximum Winds: 55 kt (100km/h)
Gusts: 70 kt (130km/h)
Minimum Central Pressure: 981 mb
WEAKENING
15P (ANA), LOCATED APPROXIMATELY 170 KM SOUTH OF SUVA, FIJI, HAS TRACKED SOUTH-SOUTHEASTWARD AT 15 KM/H
OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
-------------------------------------------------------------------------------------------------------------------
TC #17P #LUCAS  #SOUTHPACIFICOCEAN
WARNING 3
As of 12:00 UTC Jan 31, 2021:
Location: 13.1°S 155.2°E
Maximum Winds: 55 kt (100km/h)
Gusts: 70kt (130km/h)
Minimum Central Pressure: 987 mb
INTENSIFYING
17P(LUCAS), LOCATED APPROXIMATELY 1490 KM WEST-NORTHWEST OF PORT VILA, VANUATU, HAS TRACKED EAST-
NORTHEASTWARD AT 28 KM/H OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
---------------------------------------------------------------------------------------------------
TC #16P  #SOUTHPACIFICOCEAN
WARNING 4
As of 12:00 UTC Jan 31, 2021:
Location: 13.4°S 175.1°E
Maximum Winds: 45 kt (85km/h)
Gusts: 55 kt (100km/h)
Minimum Central Pressure:  993 mb
16P (SIXTEEN), LOCATED APPROXIMATELY 630 KM NORTHWEST OF SUVA, FIJI, HAS TRACKED SOUTHEASTWARD AT 26
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 1
As of 12:00 UTC Jan 31, 2021:
Location: 21.4°S 121.1°E
Maximum Winds: 30 kt (55km/h)
Gusts: 40 kt (75km/h)
Minimum Central Pressure: 998 mb
18S (EIGHTEEN), LOCATED APPROXIMATELY 730 KM EAST OF LEARMONTH, AUSTRALIA, HAS
TRACKED WEST-SOUTHWESTWARD AT 28 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 12:00 UTC Jan 31, 2021:
Location: 15.1°S 61.5°E
Maximum Winds: 30 kt ( 55km/h)
Gusts: 40 kt ( 75km/h)
Minimum Central Pressure: 1000 mb
CURRENT POTENTIAL FOR THE NEXT 24HOURS: LOW.
 
Cheers,
Patrick Hoareau
 Météo974
M974World
Cyclone Class 4
 Cheers,PH.
Joint Typhoon Warning Center

15P(ANA). WARNING 7.FORECAST TO ACCELERATE SOUTH-SOUTHEASTWARD TO SOUTHEASTWARD THROUGH 72H ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE WITH INCREASING WIND SHEAR-30-35 KNOTS. ADDITIONALLY, SEA SURFACE TEMPS VALUES ARE EXPECTED TO DECREASE TO 24-22C AFTER 48H, WHICH WILL LEAD TO MORE RAPID WEAKENING INTENSITY FALLING DOWN BELOW 35KNOTS BY 72H.
15P(ANA). WARNING 7.FORECAST TO ACCELERATE SOUTH-SOUTHEASTWARD TO SOUTHEASTWARD THROUGH 72H ALONG THE SOUTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE WITH INCREASING WIND SHEAR-30-35 KNOTS. ADDITIONALLY, SEA SURFACE TEMPS VALUES ARE EXPECTED TO DECREASE TO 24-22C AFTER 48H, WHICH WILL LEAD TO MORE RAPID WEAKENING INTENSITY FALLING DOWN BELOW 35KNOTS BY 72H.

17P(LUCAS). WARNING 3. TRACKING ALONG THE SOUTHERN PERIPHERY OF A NEAR EQUATORIAL RIDGE AND THROUGH A FAVORABLE ENVIRONMENT WITH VERY WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES, LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND ROBUST POLEWARD OUTFLOW ALOFT. THESE HIGHLY FAVORABLE CONDITIONS WILL LEAD TO RAPID INTENSIFICATION IN THE NEAR TERM AND RESULT IN AN INTENSITY OF 80 KNOTS/US CATEGORY 1 BY 24H. THEREAFTER, INCREASING VWS WILL LEAD TO A GRADUAL WEAKENING TREND AS THE SYSTEM BEGINS A GENERALLY SOUTHEASTWARD TO WEST-SOUTHWESTWARD TRACK ALONG A BUILDING SUBTROPICAL RIDGE (STR) TO THE EAST. AFTER 48H, TC LUCAS WILL BEGIN A GENERALLY SOUTHWARD TRACK AS IT BEGINS TO ROUND THE STR AXIS. HIGH (25-30 KTS) VWS WILL CONTINUE TO WEAKEN THE SYSTEM DURING THIS TIME. BY 96H THE SYSTEM WILL ROUND THE STR AXIS AND BEGIN TO DISSIPATE OVER WATER DUE TO HIGH VWS AND COOLING SST WHICH WILL LEAD TO INTENSITY FALLING DOWN BELOW 35KNOTS BY 120H.
17P(LUCAS). WARNING 3. TRACKING ALONG THE SOUTHERN PERIPHERY OF A NEAR EQUATORIAL RIDGE AND THROUGH A FAVORABLE ENVIRONMENT WITH VERY WARM (29-30 CELSIUS) SEA SURFACE TEMPERATURES, LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND ROBUST POLEWARD OUTFLOW ALOFT. THESE HIGHLY FAVORABLE CONDITIONS WILL LEAD TO RAPID INTENSIFICATION IN THE NEAR TERM AND RESULT IN AN INTENSITY OF 80 KNOTS/US CATEGORY 1 BY 24H. THEREAFTER, INCREASING VWS WILL LEAD TO A GRADUAL WEAKENING TREND AS THE SYSTEM BEGINS A GENERALLY SOUTHEASTWARD TO WEST-SOUTHWESTWARD TRACK ALONG A BUILDING SUBTROPICAL RIDGE (STR) TO THE EAST. AFTER 48H, TC LUCAS WILL BEGIN A GENERALLY SOUTHWARD TRACK AS IT BEGINS TO ROUND THE STR AXIS. HIGH (25-30 KTS) VWS WILL CONTINUE TO WEAKEN THE SYSTEM DURING THIS TIME. BY 96H THE SYSTEM WILL ROUND THE STR AXIS AND BEGIN TO DISSIPATE OVER WATER DUE TO HIGH VWS AND COOLING SST WHICH WILL LEAD TO INTENSITY FALLING DOWN BELOW 35KNOTS BY 120H.

 

16P. WARNING 4. ENVIRONMENTAL CONDITIONS ARE FORECAST TO REMAIN FAVORABLE THROUGH 12H, HOWEVER, CONDITIONS WILL DEGRADE RAPIDLY AFTER THIS TIME DUE TO STRONG VERTICAL WIND SHEAR AND INTERACTION WITH TC 15P. TC 16P IS EXPECTED TO UNDERGO BINARY INTERACTION WITH TC 15P, WHICH IS CURRENTLY LOCATED ABOUT 775KM SSE. TC 16P IS FORECAST TO TRACK SOUTHEASTWARD THROUGH 12H UNDER THE STEERING INFLUENCE OF A NEAR EQUATORIAL RIDGE POSITIONED TO THE NORTHEAST. HOWEVER, AFTER 12H, TC 16P WILL ACCELERATE SOUTH-SOUTHEASTWARD WITHIN THE EASTERN PERIPHERY OF TC 15P. BY 36H,TC 16P WILL APPROACH TC 15P WITHIN ABOUT 280KM AS IT RAPIDLY WEAKENS. BY 48H, TC 16P WILL DISSIPATE AND BECOME ABSORBED INTO TC 15P.
16P. WARNING 4. ENVIRONMENTAL CONDITIONS ARE FORECAST TO REMAIN FAVORABLE THROUGH 12H, HOWEVER, CONDITIONS WILL DEGRADE RAPIDLY AFTER THIS TIME DUE TO STRONG VERTICAL WIND SHEAR AND INTERACTION WITH TC 15P. TC 16P IS EXPECTED TO UNDERGO BINARY INTERACTION WITH TC 15P, WHICH IS CURRENTLY LOCATED ABOUT 775KM SSE. TC 16P IS FORECAST TO TRACK SOUTHEASTWARD THROUGH 12H UNDER THE STEERING INFLUENCE OF A NEAR EQUATORIAL RIDGE POSITIONED TO THE NORTHEAST. HOWEVER, AFTER 12H, TC 16P WILL ACCELERATE SOUTH-SOUTHEASTWARD WITHIN THE EASTERN PERIPHERY OF TC 15P. BY 36H,TC 16P WILL APPROACH TC 15P WITHIN ABOUT 280KM AS IT RAPIDLY WEAKENS. BY 48H, TC 16P WILL DISSIPATE AND BECOME ABSORBED INTO TC 15P.

18S. WARNING 1.TC 18S IS TRACKING OVER LAND THROUGH WESTERN AUSTRALIA, HOWEVER THE ENVIRONMENT IS OVERALL MARGINALLY FAVORABLE WITH LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND MODERATE UPPER LEVEL OUTFLOW ALOFT. THE PRIMARY STEERING MECHANISM IS A SUBTROPICAL RIDGE (STR) POSITIONED TO THE SOUTHWEST, IN ADDITION TO A SECONDARY STR TO THE EAST. TC 18S IS FORECAST TO CONTINUE TRACKING OVER WESTERN AUSTRALIA AND INTENSIFY ONLY MINIMALLY TO 35 KNOTS BY 48H, AT WHICH POINT IT WILL BE APPROXIMATELY 75 KM SOUTH OF LEARMONTH, AUSTRALIA. THEREAFTER, THE SYSTEM WILL ENTER THE WARM WATERS OF THE SOUTH INDIAN OCEAN. WARM (27-28 CELSIUS) SEA SURFACE TEMPERATURES, COUPLED WITH CONTINUED LOW VWS AND MODERATE UPPER LEVEL SUPPORT, WILL LEAD TO GRADUAL INTENSIFICATION TO A PEAK INTENSITY OF 50 KNOTS BY 72H.THEREAFTER, MODERATE (20-25 KTS) VWS AND COOLER SEAS WILL LEAD TO A GRADUAL WEAKENING TREND WITH TC 18S TRACKING SOUTHWARD AFTER 96H ALONG THE WESTERN PERIPHERY OF THE STEERING STR TO THE EAST.
18S. WARNING 1.TC 18S IS TRACKING OVER LAND THROUGH WESTERN AUSTRALIA, HOWEVER THE ENVIRONMENT IS OVERALL MARGINALLY FAVORABLE WITH LOW (10-15 KTS) VERTICAL WIND SHEAR (VWS) AND MODERATE UPPER LEVEL OUTFLOW ALOFT. THE PRIMARY STEERING MECHANISM IS A SUBTROPICAL RIDGE (STR) POSITIONED TO THE SOUTHWEST, IN ADDITION TO A SECONDARY STR TO THE EAST. TC 18S IS FORECAST TO CONTINUE TRACKING OVER WESTERN AUSTRALIA AND INTENSIFY ONLY MINIMALLY TO 35 KNOTS BY 48H, AT WHICH POINT IT WILL BE APPROXIMATELY 75 KM SOUTH OF LEARMONTH, AUSTRALIA. THEREAFTER, THE SYSTEM WILL ENTER THE WARM WATERS OF THE SOUTH INDIAN OCEAN. WARM (27-28 CELSIUS) SEA SURFACE TEMPERATURES, COUPLED WITH CONTINUED LOW VWS AND MODERATE UPPER LEVEL SUPPORT, WILL LEAD TO GRADUAL INTENSIFICATION TO A PEAK INTENSITY OF 50 KNOTS BY 72H.THEREAFTER, MODERATE (20-25 KTS) VWS AND COOLER SEAS WILL LEAD TO A GRADUAL WEAKENING TREND WITH TC 18S TRACKING SOUTHWARD AFTER 96H ALONG THE WESTERN PERIPHERY OF THE STEERING STR TO THE EAST.

15P(ANA). 31/1410UTC.ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD AREA OF FLARING DEEP CONVECTION ORIENTED EAST-WEST.
15P(ANA). 31/1410UTC.ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A BROAD AREA OF FLARING DEEP CONVECTION ORIENTED EAST-WEST.

15P(ANA). 31/1313UTC.MICROWAVE IMAGE REVEALS AN EXPOSED, DEFINED LOW-LEVEL CIRCULATION CENTER POSITIONED ON THE NORTHWEST EDGE OF A CURVED DEEP CONVECTIVE BAND WITH SHALLOW BANDING OVER THE WESTERN SEMICIRCLE.
15P(ANA). 31/1313UTC.MICROWAVE IMAGE REVEALS AN EXPOSED, DEFINED LOW-LEVEL CIRCULATION CENTER POSITIONED ON THE NORTHWEST EDGE OF A CURVED DEEP CONVECTIVE BAND WITH SHALLOW BANDING OVER THE WESTERN SEMICIRCLE.

17P(LUCAS). 31/1420UTC.ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS LOW LEVEL CLOUD LINES AND SPIRAL BANDS OF CONVECTION WRAPPING INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER.
17P(LUCAS). 31/1420UTC.ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS LOW LEVEL CLOUD LINES AND SPIRAL BANDS OF CONVECTION WRAPPING INTO AN OBSCURED LOW LEVEL CIRCULATION CENTER.

 

16P. 31/1018UTC.ASCAT-C IMAGE REVEALS A DEFINED CENTER, WHICH SUPPORTS THE INITIAL POSITION WITH FAIR CONFIDENCE, WITH 40-45 KNOT WINDS OVER THE NORTHEAST QUADRANT.
16P. 31/1018UTC.ASCAT-C IMAGE REVEALS A DEFINED CENTER, WHICH SUPPORTS THE INITIAL POSITION WITH FAIR CONFIDENCE, WITH 40-45 KNOT WINDS OVER THE NORTHEAST QUADRANT.


18S. 31/1113UTC.SATELLITE IMAGERY DEPICTS SPIRAL BANDS OF CONVECTION WRAPPING INTO A WELL DEFINED MID-LEVEL CIRCULATION CENTER TRACKING OVER WESTERN AUSTRALIA.
18S. 31/1113UTC.SATELLITE IMAGERY DEPICTS SPIRAL BANDS OF CONVECTION WRAPPING INTO A WELL DEFINED MID-LEVEL CIRCULATION CENTER TRACKING OVER WESTERN AUSTRALIA.

REMNANTS 13S. 31/1415UTC.
REMNANTS 13S. 31/1415UTC.

15P(ANA). NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK WITH A 295KM SPREAD IN MODEL SOLUTIONS AT 72H.
15P(ANA). NUMERICAL MODEL GUIDANCE REMAINS IN GOOD AGREEMENT LENDING HIGH CONFIDENCE TO THE JTWC FORECAST TRACK WITH A 295KM SPREAD IN MODEL SOLUTIONS AT 72H.

17P(LUCAS).NUMERICAL MODEL GUIDANCE IS IN POOR AGREEMENT THROUGHOUT THE LATER PORTION OF THE FORECAST PERIOD AS MODEL TRACKS DIVERGE TO A MAXIMUM 620 KM SPREAD IN SOLUTIONS AT 96H. THE GFS, ECMWF AND NAVGEM MODEL GUIDANCE PROVIDE TRACKS THAT BRING THE VORTEX OVER NEW CALEDONIA WHILE THE UKMET AND GALWEM GUIDANCE LIES TO THE EAST, RESULTING IN A TRACK THAT DOES NOT BRING THE SYSTEM CENTER OVER LAND. THIS HIGH DEGREE OF SPREAD IN MODEL SOLUTIONS LENDS FAIR CONFIDENCE IN THE INITIAL PORTION AND LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC FORECAST TRACK, WHICH IS PLACED ALONG THE MULTI- MODEL CONSENSUS.
17P(LUCAS).NUMERICAL MODEL GUIDANCE IS IN POOR AGREEMENT THROUGHOUT THE LATER PORTION OF THE FORECAST PERIOD AS MODEL TRACKS DIVERGE TO A MAXIMUM 620 KM SPREAD IN SOLUTIONS AT 96H. THE GFS, ECMWF AND NAVGEM MODEL GUIDANCE PROVIDE TRACKS THAT BRING THE VORTEX OVER NEW CALEDONIA WHILE THE UKMET AND GALWEM GUIDANCE LIES TO THE EAST, RESULTING IN A TRACK THAT DOES NOT BRING THE SYSTEM CENTER OVER LAND. THIS HIGH DEGREE OF SPREAD IN MODEL SOLUTIONS LENDS FAIR CONFIDENCE IN THE INITIAL PORTION AND LOW CONFIDENCE IN THE EXTENDED PORTION OF THE JTWC FORECAST TRACK, WHICH IS PLACED ALONG THE MULTI- MODEL CONSENSUS.

16P. THE JTWC FORECAST REMAINS CONSISTENT WITH THE PREVIOUS FORECAST TRACK AND IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS. IN LIGHT OF THE HIGHLY UNCERTAIN NATURE OF THE BINARY INTERACTION WITH TC 15P(ANA), THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK.
16P. THE JTWC FORECAST REMAINS CONSISTENT WITH THE PREVIOUS FORECAST TRACK AND IS POSITIONED CLOSE TO THE MULTI-MODEL CONSENSUS. IN LIGHT OF THE HIGHLY UNCERTAIN NATURE OF THE BINARY INTERACTION WITH TC 15P(ANA), THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK.

18S. NUMERICAL MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE GENERALLY WESTWARD TRACK THROUGH 96H BUT DIVERGE SLIGHTLY ON THE TIMING OF THE SOUTHWARD TURN THEREAFTER. THIS GOOD AGREEMENT IN NUMERICAL MODEL SOLUTIONS LENDS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED ON THE MULTI-MODEL CONSENSUS.
18S. NUMERICAL MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE GENERALLY WESTWARD TRACK THROUGH 96H BUT DIVERGE SLIGHTLY ON THE TIMING OF THE SOUTHWARD TURN THEREAFTER. THIS GOOD AGREEMENT IN NUMERICAL MODEL SOLUTIONS LENDS OVERALL HIGH CONFIDENCE IN THE JTWC FORECAST TRACK WHICH IS PLACED ON THE MULTI-MODEL CONSENSUS.
Rédigé par PATRICK HOAREAU le Sunday, January 31st 2021 à 20:10
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