Severe Tropical Cyclone Narelle is advancing along Western Australia's coast, with forecasts indicating its potential intensification and eventual landfall. This significant weather event is expected to bring destructive winds, heavy rainfall, and dangerous storm surges to various regions, including a potential indirect impact on Perth. The situation follows the recent crossing of Ex-Tropical Cyclone Mitchell on the Gascoyne coast, which delivered substantial rainfall across parts of the state.
Perth faces an uncertain but potential indirect impact, while coastal regions brace for destructive winds, heavy rainfall, and dangerous storm surges.
Cyclone Narelle's Path and Intensification
Cyclone Narelle, initially a Category 3 system that affected the Northern Territory's Top End with gusts up to 120 kilometers per hour, was reclassified as a Category 1 cyclone as it approached the Western Australian coastline. It was then expected to intensify significantly.
The system has since strengthened into a Category 3 cyclone, positioned approximately 100 kilometers offshore and moving south parallel to Western Australia's northwest coast. Further intensification to a severe Category 4 tropical cyclone was anticipated for Thursday.
The Bureau of Meteorology (BOM) also indicated a possibility that Narelle could reintensify to severe tropical cyclone strength for a third time by Wednesday as it tracked north of the Pilbara region. The cyclone was projected to move south-southwest along the Pilbara coast on Thursday before heading south on Friday, situated between north of Exmouth and south of Carnarvon.
Cyclone Narelle is likely to make landfall on Western Australia's mainland as a severe Category 3 tropical cyclone, potentially around the Shark Bay and Denham area on the Gascoyne coast, near midnight on Friday.
After tracking past Perth and heading east, Cyclone Narelle was forecast to reduce to a tropical low-pressure area, likely exiting Western Australia from its southern coastline early on Sunday.
Widespread Impacts and Coastal Warnings
Destructive conditions were expected across coastal regions due to Cyclone Narelle. Sustained winds of 150 km/h and gusts up to 200 km/h were recorded near the Pilbara coastline.
Pilbara Coast on High Alert
- Port Hedland International Airport canceled all Virgin and Qantas flights for Thursday.
- Damaging and destructive winds were anticipated on the Pilbara coast and islands.
- Karratha, Roebourne, and Port Hedland were expected to experience winds exceeding 80 km/h overnight.
- Active tropical cyclone warnings were in place from Pardoo Roadhouse to Cape Cuvier, encompassing Port Hedland, Karratha, Onslow, Exmouth, Coral Bay, and inland to Pannawonica, where winds could exceed 200 km/h later on Thursday.
Exmouth: Road Closures and Evacuation
- Main roads, including specific sections of Burkett Road, Minilya Exmouth Road, Coral Bay Road, and North West Coastal Highway, were scheduled to close from 10 am Thursday.
- An evacuation center was established at the Exmouth Shire Hall.
Gascoyne Coast: Destructive Winds and Storm Surges
- For the Shark Bay and Denham area, destructive winds and dangerous storm surges were expected late on Friday and into Saturday.
Kimberley Region: Flood Watch Issued
- A flood watch was issued for the Kimberley region, with heavy rain and deteriorating conditions expected as the system crossed from the Northern Territory into the WA coast.
- Kalumburu could see 60-120mm of rain, with isolated falls up to 200mm.
- Broome was also expected to experience rainfall.
Perth Under Watch: Uncertainties and Preparations
Perth was placed under an alert, with weather experts indicating uncertainty regarding whether the city would be directly impacted by Cyclone Narelle. If Narelle were to cross the metropolitan area, it would mark the first cyclone to hit Perth in 36 years, following significant rainfall from Cyclone Seroja in 2021.
Bureau meteorologist Helen Reid stated that precise prediction of the tropical system's path remained challenging. She noted that Perth was currently expected to be west of the storm, but uncertainties persisted. The BOM acknowledged a possibility of direct impact on Perth, though models showed a range of outcomes from near Kalbarri to south of Esperance.
Despite the ongoing uncertainty, Perth residents were advised to expect severe weather conditions throughout the week.
Wind Threat for Perth
- A severe weather warning was active for Perth, with damaging winds forecast to begin Wednesday night between Gingin and Busselton.
- Officials from the Bureau of Meteorology explained that a high-pressure system southwest of the state, combined with a trough off the west coast, would generate a vigorous easterly airstream over the Darling Scarp.
- Winds were anticipated to reach speeds between 55 and 65 km/hr, with peak gusts of 90 km/hr predicted for the Perth Hills overnight.
- Winds along the Darling Scarp, including Armadale, Ellenbrook, Kalamunda, Gingin, Dwellingup, and Harvey, were also warned to reach up to 90 km/h until approximately 10 am.
The BOM highlighted that while easterly winds are common in autumn, this week's "cyclone strength winds" posed a risk of property damage and hazardous road conditions. Residents were advised to secure loose items. Wind strengths were expected to increase throughout Thursday and Friday.
Rainfall Expectations for Perth
- Heavy rainfall was forecast for Perth on Friday and Saturday, with approximately 60mm of rain anticipated each day in one projection, and 50-100mm on Friday and into the weekend in another.
- While major flooding comparable to Narelle's impact on the Northern Territory was considered unlikely for Perth, flash flooding remained a possibility for some parts of the metropolitan region due to the speed of rainfall.
- Flash flooding warnings were issued from the North West Cape to the Swan River in Perth due to expected rainfall.
- A flood watch warning was issued on Wednesday, indicating that catchments like the Swan River might experience level rises and overflow flooding from Thursday. Roads might also be affected by flooding, and travelers were advised to check conditions.
General Advice for Residents
As the cyclone approached Western Australia, Perth residents were urged to regularly monitor weather websites for updates, as conditions could change rapidly.
Ex-Tropical Cyclone Mitchell's Recent Crossing
Ex-Tropical Cyclone Mitchell crossed the Western Australian coast early Tuesday, bringing muggy and drizzly conditions to Perth and heavy rainfall to other regions. The Bureau of Meteorology downgraded Mitchell to an ex-tropical cyclone overnight before it made landfall on the Gascoyne coast east of Shark Bay at 1 am.
Rainfall and Regional Warnings
- Significant rainfall totals were recorded, with Gascoyne Junction receiving 132mm since 9 am Monday and Shark Bay Airport recording 104.2mm in the past 48 hours.
- Several sites in the south-west Gascoyne region, including Bullardoo and Greenough River, experienced heavy rainfall, with Pindarring Rocks reporting 41.8mm in two hours.
- A severe weather warning was in effect for the central Wheatbelt and parts of the Gascoyne and Central West regions, forecasting heavy to locally intense rainfall of 25mm to 50mm, which could cause flash flooding.
- A cyclone advice warning for Shark Bay and Denham, including Monkey Mia, remained in place, though the threat level had decreased.
- Additionally, a minor flood warning was issued for the Fitzroy River at Fitzroy Crossing in the Kimberley, alongside anticipated "small" river rises along the Moore River.
Perth's Experience with Mitchell
The ex-tropical cyclone was moving south-easterly and was expected to weaken, sparing the Perth metropolitan area the main impact.
Perth recorded 2.2mm of rain in the last 24 hours due to its location on the periphery of Mitchell's cloud band. Showers were forecast to clear gradually on Tuesday afternoon, with muggy conditions persisting throughout the day. The metropolitan area was expected to dry out from Wednesday, with a forecast of sunny weather and maximum temperatures between 28C and 30C through Monday.