SOUTH PACIFIC: Super Cyclone 23P(NIRAN) has reached US/Category 5, bearing down on Noumea/New Caledonia


23P(NIRAN). 05/1435UTC. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THAT TC 23P HAS UNDERGONE A PERIOD OF EXTREME RAPID INTENSIFICATION (ERI), HAVING INTENSIFIED 30 KNOTS IN SIX HOURS, WITH DEVELOPMENT OF A VERY COMPACT 19KM EYE, SURROUNDED BY A UNIFORM RING OF VERY COLD CONVECTIVE CLOUD TOPS. IF NEEDED CLICK ON THE IMAGERY TO SEE THE ANIMATION.


23P(NIRAN). 05/1435UTC. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THAT TC 23P HAS UNDERGONE A  PERIOD OF EXTREME RAPID INTENSIFICATION (ERI), HAVING INTENSIFIED 30  KNOTS IN SIX HOURS, WITH DEVELOPMENT OF A VERY COMPACT 19KM EYE,  SURROUNDED BY A UNIFORM RING OF VERY COLD CONVECTIVE CLOUD TOPS. IF NEEDED CLICK ON THE IMAGERY TO SEE THE ANIMATION.
23P(NIRAN). 05/1435UTC. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THAT TC 23P HAS UNDERGONE A PERIOD OF EXTREME RAPID INTENSIFICATION (ERI), HAVING INTENSIFIED 30 KNOTS IN SIX HOURS, WITH DEVELOPMENT OF A VERY COMPACT 19KM EYE, SURROUNDED BY A UNIFORM RING OF VERY COLD CONVECTIVE CLOUD TOPS. IF NEEDED CLICK ON THE IMAGERY TO SEE THE ANIMATION.
2021 MAR 05 15UTC #SOUTHERNHEMISPHERE
Super TC #23P #NIRAN  #SOUTHPACIFICOCEAN #CORALSEA
WARNING 19
As of 12:00 UTC Mar 05, 2021:
Location: 18.8°S 159.1°E
Maximum Winds: 140 kt ( 260km/h)
Gusts: 170 kt ( 315km/h)
Minimum Central Pressure: 917mb
CATEGORY US: 5
PEAK INTENSITY LIKELY
LOCATED AT 05/12UTC APPROXIMATELY 815KM WEST-NORTHWEST OF NOUMEA, NEW CALEDONIA, HAS TRACKED EAST-
SOUTHEASTWARD AT 44 KM/H OVER THE PAST SIX HOURS.

 Satellite bulletins are to be found in the comments of this post on JTWC BIS
 

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

Joint Typhoon Warning Center

23P(NIRAN). WARNING 19 ISSUED AT 05/15UTC.THE ENVIRONMENT IS GENERALLY FAVORABLE, THOUGH VERTICAL WIND SHEAR  IS INCREASING TO 20 TO 25 KTS. HOWEVER, THE SHEAR VECTOR IS IN PHASE  WITH THE STORM MOTION RESULTING IN SOMEWHAT LOWER RELATIVE WIND SHEAR  WHICH, COMBINED WITH WARM (28-29C) SSTS AND VERY STRONG POLEWARD  OUTFLOW, HAS ENABLED THE RECENT EXTREMELY RAPID INTENSIFICATION. TC 23P IS MOVING RAPIDLY  SOUTHEASTWARD IN THE TIGHT UPPER-LEVEL GRADIENT BETWEEN A DEEP-LAYER  RIDGE COMPLEX EXTENDING FROM FIJI NORTHWEST TO THE EQUATOR AND AN  APPROACHING MAJOR SHORTWAVE TROUGH APPROACHING FROM THE WEST. THIS  SOUTHEASTWARD MOTION IS FORECAST TO CONTINUE THROUGH 48H, BEFORE  TURNING MORE EASTWARD AT 72H. TC 23P IS FORECAST TO SLOWLY WEAKEN  OVER THE NEXT 12 HOURS AS THE ROBUST POLEWARD OUTFLOW OFFSETS THE  STEADILY INCREASING, BUT IN PHASE, WIND SHEAR. AFTER 24H THE RATE OF  WEAKENING WILL INCREASE AS DIFFLUENT UPPER-LEVEL OUTFLOW WEAKENS,  WIND SHEAR INCREASES AND THE SYSTEM MOVES OVER COOLER WATERS. THE SYSTEM  WILL BEGIN SUBTROPICAL TRANSITION BY 36H AS IT MOVES BEGINS TO  INTERACT WITH AND EVENTUALLY MOVE UNDER THE APPROACHING TROUGH AND  INTO MUCH COOLER WATERS. TRANSITION TO A STORM FORCE SUBTROPICAL LOW  IS EXPECTED NO LATER THAN 72H, OR POTENTIALLY AS EARLY AS 60H.
23P(NIRAN). WARNING 19 ISSUED AT 05/15UTC.THE ENVIRONMENT IS GENERALLY FAVORABLE, THOUGH VERTICAL WIND SHEAR IS INCREASING TO 20 TO 25 KTS. HOWEVER, THE SHEAR VECTOR IS IN PHASE WITH THE STORM MOTION RESULTING IN SOMEWHAT LOWER RELATIVE WIND SHEAR WHICH, COMBINED WITH WARM (28-29C) SSTS AND VERY STRONG POLEWARD OUTFLOW, HAS ENABLED THE RECENT EXTREMELY RAPID INTENSIFICATION. TC 23P IS MOVING RAPIDLY SOUTHEASTWARD IN THE TIGHT UPPER-LEVEL GRADIENT BETWEEN A DEEP-LAYER RIDGE COMPLEX EXTENDING FROM FIJI NORTHWEST TO THE EQUATOR AND AN APPROACHING MAJOR SHORTWAVE TROUGH APPROACHING FROM THE WEST. THIS SOUTHEASTWARD MOTION IS FORECAST TO CONTINUE THROUGH 48H, BEFORE TURNING MORE EASTWARD AT 72H. TC 23P IS FORECAST TO SLOWLY WEAKEN OVER THE NEXT 12 HOURS AS THE ROBUST POLEWARD OUTFLOW OFFSETS THE STEADILY INCREASING, BUT IN PHASE, WIND SHEAR. AFTER 24H THE RATE OF WEAKENING WILL INCREASE AS DIFFLUENT UPPER-LEVEL OUTFLOW WEAKENS, WIND SHEAR INCREASES AND THE SYSTEM MOVES OVER COOLER WATERS. THE SYSTEM WILL BEGIN SUBTROPICAL TRANSITION BY 36H AS IT MOVES BEGINS TO INTERACT WITH AND EVENTUALLY MOVE UNDER THE APPROACHING TROUGH AND INTO MUCH COOLER WATERS. TRANSITION TO A STORM FORCE SUBTROPICAL LOW IS EXPECTED NO LATER THAN 72H, OR POTENTIALLY AS EARLY AS 60H.

23P(NIRAN). WARNING 19. FORECAST CLOSEST POINT OF APPROACH TO NOUMEA IS 17KM BY 06/06UTC.
23P(NIRAN). WARNING 19. FORECAST CLOSEST POINT OF APPROACH TO NOUMEA IS 17KM BY 06/06UTC.


22P(NIRAN). NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT, WITH 280kM SPREAD AT  36h. GUIDANCE IS IN POOR AGREEMENT AFTER 36h, WITH A 1085kM  SPREAD BY 72H. THE JTWC FORECAST LIES NEAR THE CONSENSUS MEAN  THROUGH 36H, THEN TRACKS THE NORTHERN EDGE OF THE BULK OF THE  GUIDANCE AND CLOSE TO THE ECMWF SOLUTION THOUGH 72H. IN LIGHT OF  THE UNCERTAINTY SEEN IN THE LATER TAUS, THERE IS HIGH CONFIDENCE IN  THE FIRST 36 HOURS AND LOW CONFIDENCE THEREAFTER.
22P(NIRAN). NUMERICAL MODEL GUIDANCE IS IN GOOD AGREEMENT, WITH 280kM SPREAD AT 36h. GUIDANCE IS IN POOR AGREEMENT AFTER 36h, WITH A 1085kM SPREAD BY 72H. THE JTWC FORECAST LIES NEAR THE CONSENSUS MEAN THROUGH 36H, THEN TRACKS THE NORTHERN EDGE OF THE BULK OF THE GUIDANCE AND CLOSE TO THE ECMWF SOLUTION THOUGH 72H. IN LIGHT OF THE UNCERTAINTY SEEN IN THE LATER TAUS, THERE IS HIGH CONFIDENCE IN THE FIRST 36 HOURS AND LOW CONFIDENCE THEREAFTER.

23P(NIRAN). 05/1230UTC.VERY COMPACT 19KM EYE, SURROUNDED BY A UNIFORM RING OF VERY COLD CONVECTIVE CLOUD TOPS.
23P(NIRAN). 05/1230UTC.VERY COMPACT 19KM EYE, SURROUNDED BY A UNIFORM RING OF VERY COLD CONVECTIVE CLOUD TOPS.

23P(NIRAN). 05/1059UTC.
23P(NIRAN). 05/1059UTC.

23P(NIRAN). 05/0854UTC. DMSP. THE EXTREMELY RAPID INTENSIFICATION EVENT WAS JUST BEGINING.
23P(NIRAN). 05/0854UTC. DMSP. THE EXTREMELY RAPID INTENSIFICATION EVENT WAS JUST BEGINING.

Rédigé par PATRICK HOAREAU le Vendredi 5 Mars 2021 à 19:15