Australia’s Impacts from Severe Tropical Cyclone Errol

Tuesday, April 15, 2025:

• Night (AWST): Tropical Cyclone Errol forms to the north of Western Australia (WA).

Wednesday, April 16, 2025:

• Early Thursday (AWST): Errol strengthens to a tropical cyclone in the Indian Ocean, according to the Joint Typhoon Warning Center (JTWC).
• 8:00 AM AWST: Errol is a category two tropical cyclone located roughly 515 km to the north northwest of Broome, moving west.
• Wednesday Afternoon (AWST): Errol intensifies into a category three severe tropical cyclone. Its center has winds reaching 150 kilometers per hour.
• During the day (AWST): Satellite imagery shows Errol with an approximately 8 nautical mile wide eye surrounded by a solid central dense overcast. The eye temperature is a positive 15°C.
• By 2:00 PM AWST: Satellite data indicates a symmetrical eye, suggesting the storm is not encountering weakening factors.
• Afternoon/Evening (AWST): Errol undergoes an amazing period of extreme rapid intensification, intensifying 85 knots in the last 24 hours and more than 50 knots in the last 12 hours.
• Between approximately 7:41 AM and 8:05 AM UTC (equivalent to afternoon AWST): Microwave passes suggest Errol completed a rapid eyewall replacement cycle (ERC).
• By 15:00 UTC (11:00 PM AWST): JTWC's initial position assessment places Errol at 14.4S 118.9E, about 283 nautical miles northwest of Broome, Australia, with an initial intensity of 140 knots (approximately 161 mph). Significant wave height is 47 feet. Errol is moving southwestward at 4 knots. JTWC assesses that Errol has likely reached its peak intensity.
• 19:27 UTC (Early Thursday morning AWST, April 17th): The Australian Bureau of Meteorology (BOM) issues Tropical Cyclone Technical Bulletin 1, identifying Severe Tropical Cyclone Errol (Category 4 equivalent based on 10-minute winds of 100 knots/185 km/h and 3-second gusts of 140 knots/260 km/h). Its location is 14.7S 118.8E, moving south at 4 knots. Central pressure is 946 hPa. BOM notes the eye is showing some weakening and cloud top warming to the northeast of the center, indicating peak intensity has likely been reached. They forecast weakening as Errol approaches the west Kimberley coast.

Thursday, April 17, 2025:

• By Thursday Morning (AWST): Forecast models suggest Errol could briefly intensify into a category 4 system (Australian scale).
• Thursday (AWST): Errol is expected to make a left-hand (eastward) turn and start moving towards WA’s Kimberley coast.
• Throughout the day (AWST): Increasing vertical wind shear and dry air intrusion are expected to become less favorable for Errol to maintain its strength after it turns south.

Friday, April 18, 2025:

• Errol is expected to weaken as it approaches the Kimberley coast.
• A tropical cyclone watch is expected to be issued for gale force winds to develop in 48 hours for the exposed islands of the Kimberley coast (Friday night or early Saturday).
• Isolated heavy rainfall could develop between Kuri Bay and Broome overnight and persist during Saturday morning as Errol moves closer.

Saturday, April 19, 2025:

• Errol is most likely to make landfall as a tropical low (below tropical cyclone strength) this weekend, potentially on Saturday morning near Cape Leveque or Cockatoo Island.
• Damaging winds could extend southwards from Beagle Bay to Broome depending on the track