SOUTH PACIFIC: 23P(NIRAN), still a US/CAT 2 but will rapidly become subtropical and weaken drastically next 36h, 06/15utc update



2021 MAR 06 15UTC #SOUTHERNHEMISPHERE
 TC #23P #NIRAN  #SOUTHPACIFICOCEAN #CORALSEA
WARNING 23
As of 12:00 UTC Mar 06, 2021:
Location: 24.3°S 169.5°E
Maximum Winds: 90 kt ( 165km/h)
Gusts: 110 kt ( 205km/h)
Minimum Central Pressure: 959mb
CATEGORY US: 2
WEAKENING AND BECOMING SUBTROPICAL
LOCATED AT 06/12UTC APPROXIMATELY 425KM SOUTHEAST OF NOUMEA, NEW CALEDONIA, HAS TRACKED EAST-SOUTHEASTWARD AT 57 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 23 ISSUED AT 06/15UTC. UPPER LEVEL ANALYSIS INDICATES ROBUST POLEWARD OUTFLOW THAT IS OFFSET BY STRONG  (30KTS+) VERTICAL WIND SHEAR. SEA SURFACE TEMPERATURES (SSTS) HAVE  ALSO DROPPED TO 26C. THE CYCLONE WILL CONTINUE TO ACCELERATE  SOUTHEASTWARD ALONG THE SOUTHWEST PERIPHERY OF THE DEEP LAYERED  SUBTROPICAL RIDGE TO THE EAST. THE UNFAVORABLE ENVIRONMENT WILL  SUSTAIN THE RAPID WEAKENING DOWN TO 40KNOTS BY 36H. CONCURRENTLY, TC  NIRAN WILL BEGIN SUBTROPICAL TRANSITION BY 12H AND BY 36H WILL  BECOME A GALE-FORCE SUBTROPICAL LOW, POSSIBLY SOONER.
23P(NIRAN). WARNING 23 ISSUED AT 06/15UTC. UPPER LEVEL ANALYSIS INDICATES ROBUST POLEWARD OUTFLOW THAT IS OFFSET BY STRONG (30KTS+) VERTICAL WIND SHEAR. SEA SURFACE TEMPERATURES (SSTS) HAVE ALSO DROPPED TO 26C. THE CYCLONE WILL CONTINUE TO ACCELERATE SOUTHEASTWARD ALONG THE SOUTHWEST PERIPHERY OF THE DEEP LAYERED SUBTROPICAL RIDGE TO THE EAST. THE UNFAVORABLE ENVIRONMENT WILL SUSTAIN THE RAPID WEAKENING DOWN TO 40KNOTS BY 36H. CONCURRENTLY, TC NIRAN WILL BEGIN SUBTROPICAL TRANSITION BY 12H AND BY 36H WILL BECOME A GALE-FORCE SUBTROPICAL LOW, POSSIBLY SOONER.

23P(NIRAN). NUMERICAL MODELS ARE IN GOOD AGREEMENT 24H. AFTERWARD, THE SOLUTIONS  DIVERGE. THERE IS HIGH CONFIDENCE IN THE FIRST 24 HOURS OF THE  FORECAST TRACK AND LOW CONFIDENCE THEREAFTER DUE TO THE INCREASING  SPREAD IN MODEL SOLUTIONS.
23P(NIRAN). NUMERICAL MODELS ARE IN GOOD AGREEMENT 24H. AFTERWARD, THE SOLUTIONS DIVERGE. THERE IS HIGH CONFIDENCE IN THE FIRST 24 HOURS OF THE FORECAST TRACK AND LOW CONFIDENCE THEREAFTER DUE TO THE INCREASING SPREAD IN MODEL SOLUTIONS.

23P(NIRAN). 06/1430UTC. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM HAS CONTINUED TO ELONGATED WITH  FRONTAL CHARACTERISTICS MORE PRONOUNCED AS IT ACCELERATED TO THE SOUTHEAST.
23P(NIRAN). 06/1430UTC. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY SHOWS THE SYSTEM HAS CONTINUED TO ELONGATED WITH FRONTAL CHARACTERISTICS MORE PRONOUNCED AS IT ACCELERATED TO THE SOUTHEAST.

23P(NIRAN). THE INITIAL POSITION WAS PLACED WITH HIGH CONFIDENCE BASED  ON A CIRCULATION FEATURE IN THE 06/1059UTC ASCAT BULLSEYE PASS.
23P(NIRAN). THE INITIAL POSITION WAS PLACED WITH HIGH CONFIDENCE BASED ON A CIRCULATION FEATURE IN THE 06/1059UTC ASCAT BULLSEYE PASS.

23P(NIRAN). 06/12UTC.
23P(NIRAN). 06/12UTC.
Rédigé par PATRICK HOAREAU le Samedi 6 Mars 2021 à 19:20