Southern Hemisphere: 15P(ANA) & 16P forecast interaction over the South Pacific, 30/21utc updates


INVEST 99P IS NOW TC 16P. JTWC HAS BEEN ISSUING 6HOURLY WARNINGS ON 15P(ANA) AND 16P(NONAME). 3HOURLY SATELLITE BULLETINS ARE PROVIDED FOR 15P AND 16P ALONG WITH INVEST 94P AND INVEST 98S.


INVEST 99P IS NOW TC 16P. JTWC HAS BEEN ISSUING 6HOURLY WARNINGS ON 15P(ANA) AND 16P(NONAME). 3HOURLY SATELLITE BULLETINS ARE PROVIDED FOR 15P AND 16P ALONG WITH INVEST 94P AND INVEST 98S.
INVEST 99P IS NOW TC 16P. JTWC HAS BEEN ISSUING 6HOURLY WARNINGS ON 15P(ANA) AND 16P(NONAME). 3HOURLY SATELLITE BULLETINS ARE PROVIDED FOR 15P AND 16P ALONG WITH INVEST 94P AND INVEST 98S.
2021 JAN 30 2325UTC #SOUTHERNHEMISPHERE
TC #15P #ANA #SOUTHPACIFICOCEAN
WARNING 4/UPDATE
As of 18:00 UTC Jan 30, 2021:
Location: 17.5°S 178.2°E
Maximum Winds: 60 kt (110km/h)
Gusts: 75 kt (140km/h)
Minimum Central Pressure: 978 mb
INTENSIFYING
15P (ANA), LOCATED AT 30/18UTC APPROXIMATELY 70KM NORTH-NORTHWEST OF SUVA/FIJI, HAS TRACKED SOUTHEASTWARD AT 17 KM/H OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
-------------------------------------------------------------------------------------------------------------------
INVEST #94P  #SOUTHPACIFICOCEAN
UPDATE/TCFA
As of 18:00 UTC Jan 30, 2021:
Location: 13.9°S 151.5°E
Maximum Winds: 30 kt (55km/h)
Gusts: 40 kt (75km/h)
Minimum Central Pressure: 997 mb
CURRENT POTENTIAL FOR THE NEXT 24HOURS: HIGH
Satellite bulletins are to be found in the comments of this post on JTWC BIS
---------------------------------------------------------------------------------------------------
TC #16P  #SOUTHPACIFICOCEAN
WARNING 1/UPDATE
As of 18:00 UTC Jan 30, 2021:
Location: 11.9°S 171.4°E
Maximum Winds: 35 kt (65km/h)
Gusts: 45 kt (85km/h)
Minimum Central Pressure:  994 mb
16P (SIXTEEN), LOCATED AT 30/18UTC APPROXIMATELY
725 KM NORTH-NORTHEAST OF PORT VILA, VANUATU, HAS TRACKED
EASTWARD AT 39 KM/H OVER THE PAST SIX HOURS.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
----------------------------------------------------------------------------------------------------------------
INVEST #98S  #SOUTHINDIANOCEAN
TCFA/UPDATE
As of 18:00 UTC Jan 30, 2021:
Location: 19.2°S 123.5°E
Maximum Winds: 30 kt (55km/h)
Gusts: 40 kt (75km/h)
Minimum Central Pressure: 996 mb
CURRENT POTENTIAL FOR THE NEXT 24HOURS: UP-GRADED TO HIGH.
Satellite bulletins are to be found in the comments of this post on JTWC BIS
-----------------------------------------------------------------------------------------------------------------------
REMNANTS #13S  #SOUTHINDIANOCEAN
UPDATE
As of 18:00 UTC Jan 30, 2021:
Location: 15.4°S 67.6°E
Maximum Winds: 25 kt
Gusts: 35 kt
Minimum Central Pressure: 1004 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 4. THE COMBINATION OF SURFACE  OBSERVATIONS FROM RAKIRAKI (91669) AND VIWA ISLAND (91670, AS WELL  AS ANIMATED RADAR DATA FROM FIJI WHICH DEPICTED A WEAK RADAR EYE,  LENT HIGH CONFIDENCE TO THE INITIAL POSITION. BASED ON THE RADAR  DATA, IT APPEARS THAT THE CENTER OF TC ANA CROSSED VERY CLOSE TO  RAKIRAKI, SO THE 1800UTC PRESSURE READING OF 978MB, WHICH CORRESPONDS  TO ABOUT 60 KNOTS, LIKELY IS A VERY CLOSE ESTIMATION OF THE ACTUAL  CENTER PRESSURE OF THE SYSTEM. UPPER-LEVEL ANALYSIS INDICATES  FAVORABLE ENVIRONMENTAL CONDITIONS WITH LOW (5-10KT) WIND SHEAR, AND STRONG  OUTFLOW BOTH EQUATORWARD AND POLEWARD PROVIDED BY A SMALL POINT  SOURCE WHICH HAS RECENTLY DEVELOPED OVER TOP OF THE SYSTEM, WHICH IS  FIGHTING OFF THE PREDOMINANT WESTERLY SHEAR. SEA SURFACE TEMPS (28-29C) ALSO  REMAIN CONDUCIVE TO FURTHER DEVELOPMENT. IN THE NEAR-TERM,  INTERACTION WITH VITU LEVU WILL LIMIT POTENTIAL INTENSIFCATION  AND THUS INTENSITY IS FORECAST TO REMAIN STEADY THROUGH 12H. ONCE  THE CENTER MOVES SOUTH OF THE MAIN ISLANDS, IT IS FORECAST TO AGAIN  INTENSIFY, PEAKING AT 65 KNOTS/US CATEGORY 1 BY 24H. AFTER THIS POINT, THE  SYSTEM IS EXPECTED TO ACCELERATE SOUTHEASTWARD ALONG THE WESTERN  PERIPHERY OF A DEEP-LAYER STR LOCATED TO THE EAST, WITH INCREASING  WIND SHEAR STEADILY, IF SLOWLY INCREASING. AFTER 48H THE SYSTEM BEGINS  TO MOVE OVER COOLER WATERS AND ENCOUNTERS HIGH (25-35 KT) WIND SHEAR  ASSOCIATED WITH STRONG MID-LATITUDE WESTERLY FLOW ALOFT. THE INTENSITY IS FORECAST TO FALL BELOW 35KNOTS AT OR BEFORE 120H.
15P(ANA). WARNING 4. THE COMBINATION OF SURFACE OBSERVATIONS FROM RAKIRAKI (91669) AND VIWA ISLAND (91670, AS WELL AS ANIMATED RADAR DATA FROM FIJI WHICH DEPICTED A WEAK RADAR EYE, LENT HIGH CONFIDENCE TO THE INITIAL POSITION. BASED ON THE RADAR DATA, IT APPEARS THAT THE CENTER OF TC ANA CROSSED VERY CLOSE TO RAKIRAKI, SO THE 1800UTC PRESSURE READING OF 978MB, WHICH CORRESPONDS TO ABOUT 60 KNOTS, LIKELY IS A VERY CLOSE ESTIMATION OF THE ACTUAL CENTER PRESSURE OF THE SYSTEM. UPPER-LEVEL ANALYSIS INDICATES FAVORABLE ENVIRONMENTAL CONDITIONS WITH LOW (5-10KT) WIND SHEAR, AND STRONG OUTFLOW BOTH EQUATORWARD AND POLEWARD PROVIDED BY A SMALL POINT SOURCE WHICH HAS RECENTLY DEVELOPED OVER TOP OF THE SYSTEM, WHICH IS FIGHTING OFF THE PREDOMINANT WESTERLY SHEAR. SEA SURFACE TEMPS (28-29C) ALSO REMAIN CONDUCIVE TO FURTHER DEVELOPMENT. IN THE NEAR-TERM, INTERACTION WITH VITU LEVU WILL LIMIT POTENTIAL INTENSIFCATION AND THUS INTENSITY IS FORECAST TO REMAIN STEADY THROUGH 12H. ONCE THE CENTER MOVES SOUTH OF THE MAIN ISLANDS, IT IS FORECAST TO AGAIN INTENSIFY, PEAKING AT 65 KNOTS/US CATEGORY 1 BY 24H. AFTER THIS POINT, THE SYSTEM IS EXPECTED TO ACCELERATE SOUTHEASTWARD ALONG THE WESTERN PERIPHERY OF A DEEP-LAYER STR LOCATED TO THE EAST, WITH INCREASING WIND SHEAR STEADILY, IF SLOWLY INCREASING. AFTER 48H THE SYSTEM BEGINS TO MOVE OVER COOLER WATERS AND ENCOUNTERS HIGH (25-35 KT) WIND SHEAR ASSOCIATED WITH STRONG MID-LATITUDE WESTERLY FLOW ALOFT. THE INTENSITY IS FORECAST TO FALL BELOW 35KNOTS AT OR BEFORE 120H.

15P(ANA).30/21UTC.ANIMATED ENHANCED INFRARED (EIR)  SATELLITE IMAGERY DEPICTS A RAPIDLY DEVELOPING SYSTEM, WITH DEEP  SYMMETRICAL CONVECTION FORMING A CENTRAL DENSE OVERCAST OBSCURING  THE LOW LEVEL CIRCULATION CENTER (LLCC).
15P(ANA).30/21UTC.ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A RAPIDLY DEVELOPING SYSTEM, WITH DEEP SYMMETRICAL CONVECTION FORMING A CENTRAL DENSE OVERCAST OBSCURING THE LOW LEVEL CIRCULATION CENTER (LLCC).

15P(ANA). NUMERICAL MODEL GUIDANCE IS IN RELATIVELY GOOD CROSS-TRACK  AGREEMENT, WITH 240KM SPREAD AT 48H, AND DECREASING THEREAFTER.  HOWEVER, THERE ARE SIGNIFICANT ALONG-TRACK DIFFERENCES, PARTICUARLY  AFTER 72H, AS WOULD BE EXPECTED FOR A SYSTEM MOVING RAPIDLY INTO  THE SUBTROPICS, WITH UP TO 2400KM SPREAD AT 120H BETWEEN THE GFS  AND ECMWF. THE JTWC FORECAST TRACK LIES JUST EAST AND SLIGHTLY  SLOWER THAN THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE THROUGH  48H AND LOW CONFIDENCE THEREAFTER, AS ALONG-TRACK SPREAD  INCREASES.
15P(ANA). NUMERICAL MODEL GUIDANCE IS IN RELATIVELY GOOD CROSS-TRACK AGREEMENT, WITH 240KM SPREAD AT 48H, AND DECREASING THEREAFTER. HOWEVER, THERE ARE SIGNIFICANT ALONG-TRACK DIFFERENCES, PARTICUARLY AFTER 72H, AS WOULD BE EXPECTED FOR A SYSTEM MOVING RAPIDLY INTO THE SUBTROPICS, WITH UP TO 2400KM SPREAD AT 120H BETWEEN THE GFS AND ECMWF. THE JTWC FORECAST TRACK LIES JUST EAST AND SLIGHTLY SLOWER THAN THE MULTI-MODEL CONSENSUS WITH HIGH CONFIDENCE THROUGH 48H AND LOW CONFIDENCE THEREAFTER, AS ALONG-TRACK SPREAD INCREASES.

16P. WARNING 1.THE INITIAL POSITION IS ASSESSED  WITH MODERATE CONFIDENCE. THE INITIAL INTENSITY IS SET AT 35 KNOTS.16P IS TRACKING QUICKLY TOWARDS THE EAST UNDER THE  STEERING INFLUENCE OF A LOW TO MID-LEVEL NEAR EQUATORIAL RIDGE (NER)  CENTERED TO THE NORTH. OVER THE NEXT 24 TO 36 HOURS, THE SYSTEM IS  FORECAST TO TURN TOWARDS THE SOUTHEAST AS THE PRIMARY STEERING  MECHANISM SHIFTS TO THE SUBTROPICAL RIDGE (STR) CENTERED TO THE  EAST. AFTER 36H, THE SYSTEM WILL BEGIN TO INTERACT WITH AND  BECOME CAPTURED BY TC 15P SOUTH OF FIJI, ULTIMATELY BECOMING  ABSORBED BY TC 15P BY 72H. OVER THE NEXT 24 HOURS THE SYSTEM  SHOULD REMAIN IN AN AREA OF FAVORABLE CONDITIONS, ALLOWING FOR A  SHORT BURST OF INTENSIFICATION TO A PEAK OF 45 KNOTS BY 24H.  THEREAFTER THE SYSTEM WILL SLOWLY WEAKEN AS IT ENCOUNTERS INCREASING  WIND SHEAR AND CONVERGENT FLOW ALOFT EMANATING FROM THE OUTFLOW ASSOCIATED  WITH TC 15P. AS THE SYSTEM CLOSES AND MERGES WITH TC 15P, THE  COMBINATION OF THE CONVERGENT FLOW ALOFT, COOLER SEAS AND DISRUPTION  OF THE LOW-LEVEL INFLOW WILL LEAD TO DISSIPATION AS A DISTINCT  TROPICAL CYCLONE BY 72H.
16P. WARNING 1.THE INITIAL POSITION IS ASSESSED WITH MODERATE CONFIDENCE. THE INITIAL INTENSITY IS SET AT 35 KNOTS.16P IS TRACKING QUICKLY TOWARDS THE EAST UNDER THE STEERING INFLUENCE OF A LOW TO MID-LEVEL NEAR EQUATORIAL RIDGE (NER) CENTERED TO THE NORTH. OVER THE NEXT 24 TO 36 HOURS, THE SYSTEM IS FORECAST TO TURN TOWARDS THE SOUTHEAST AS THE PRIMARY STEERING MECHANISM SHIFTS TO THE SUBTROPICAL RIDGE (STR) CENTERED TO THE EAST. AFTER 36H, THE SYSTEM WILL BEGIN TO INTERACT WITH AND BECOME CAPTURED BY TC 15P SOUTH OF FIJI, ULTIMATELY BECOMING ABSORBED BY TC 15P BY 72H. OVER THE NEXT 24 HOURS THE SYSTEM SHOULD REMAIN IN AN AREA OF FAVORABLE CONDITIONS, ALLOWING FOR A SHORT BURST OF INTENSIFICATION TO A PEAK OF 45 KNOTS BY 24H. THEREAFTER THE SYSTEM WILL SLOWLY WEAKEN AS IT ENCOUNTERS INCREASING WIND SHEAR AND CONVERGENT FLOW ALOFT EMANATING FROM THE OUTFLOW ASSOCIATED WITH TC 15P. AS THE SYSTEM CLOSES AND MERGES WITH TC 15P, THE COMBINATION OF THE CONVERGENT FLOW ALOFT, COOLER SEAS AND DISRUPTION OF THE LOW-LEVEL INFLOW WILL LEAD TO DISSIPATION AS A DISTINCT TROPICAL CYCLONE BY 72H.

16P. 30/21UTC. ANIMATED ENHANCED  INFRARED (EIR) SATELLITE IMAGERY DEPICTS TWO AREAS OF COMPACT DEEP  CONVECTION, ONE NEAR THE ASSESSED CENTER AND THE OTHER DISPLACED TO  THE NORTH, WITH LOW-LEVEL BANDS WRAPPING INTO THE SOUTHERN  CONVECTIVE AREA.
16P. 30/21UTC. ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TWO AREAS OF COMPACT DEEP CONVECTION, ONE NEAR THE ASSESSED CENTER AND THE OTHER DISPLACED TO THE NORTH, WITH LOW-LEVEL BANDS WRAPPING INTO THE SOUTHERN CONVECTIVE AREA.

16P. NUMERICAL MODEL GUIDANCE IS IN GOOD  AGREEMENT ON THE OVERALL SCENARIO AT LEAST THROUGH 36H WITH  INCREASING UNCERTAINTY THEREAFTER AS THE SYSTEM INTERACTS WITH TC  15P. THE JTWC FORECAST TRACK LIES TO THE NORTH AND EAST OF THE MULT- MODEL CONSENSUS IN LIGHT OF RECENT MOTION THOUGH 36H, THEN VERY  NEAR THE CONSENSUS THROUGH THE REMAINDER OF THE FORECAST. HOWEVER  DUE TO THE HIGHLY UNCERTAIN NATURE OF THE POTENTIAL INTERACTION WITH  TC 15P, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST.
16P. NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT ON THE OVERALL SCENARIO AT LEAST THROUGH 36H WITH INCREASING UNCERTAINTY THEREAFTER AS THE SYSTEM INTERACTS WITH TC 15P. THE JTWC FORECAST TRACK LIES TO THE NORTH AND EAST OF THE MULT- MODEL CONSENSUS IN LIGHT OF RECENT MOTION THOUGH 36H, THEN VERY NEAR THE CONSENSUS THROUGH THE REMAINDER OF THE FORECAST. HOWEVER DUE TO THE HIGHLY UNCERTAIN NATURE OF THE POTENTIAL INTERACTION WITH TC 15P, THERE IS OVERALL LOW CONFIDENCE IN THE JTWC FORECAST.

30/2355UTC. SOUTH PACIFIC BEING VERY BUSY.
30/2355UTC. SOUTH PACIFIC BEING VERY BUSY.
Rédigé par PATRICK HOAREAU le Dimanche 31 Janvier 2021 à 04:20