Australian Weather

22 Oct 2026, 4:54AM UTC

Close to 300 mm of rain has fallen in parts of southeast Queensland between Wednesday morning and Thursday afternoon. This deluge has broken October records and caused dangerous flash flooding. So, why has there been so much rain in the last couple of days? There are three main ingredients needed for heavy rain and thunderstorms: Moisture Atmospheric instability Trigger mechanism Moisture sources converging over eastern Australia The main ingredient you need for heavy rain is moisture and this has been available in abundance over southern Queensland and northern NSW in the last two days. Two separate moisture sources are converging over eastern Australia this week. One is coming from the Indian Ocean and flowing across Australia from the west, providing moisture-laden air in the middle and upper levels of the atmosphere. Another stream of moisture is also flowing over Australia from the east, transporting atmospheric moisture from the Coral and Tasman Seas towards eastern Australia. Image: Precipitable water and 850 hPa winds at 5 pm AEDT on Thursday, October 22, 2026. Source: Weatherzone. A weather balloon released from Brisbane Airport on Thursday morning showed that the atmosphere was loaded with moisture from the ground all the way up to about 9 km above the surface. This deep layer of atmospheric moisture is providing ample fuel for sustained and heavy rainfall in southeast Queensland and northeast NSW. Upper-level low providing instability A slow-moving upper-level low pressure system is located over northern NSW on Thursday. This system is associated with a pool of relatively cold air in the upper atmosphere. When cold air sits above warmer air, it causes atmospheric instability that encourages air to lift. This lifting helps create the towering clouds needed to produce heavy rain and thunderstorms. Image: 500 hPa temperature and height, showing an upper-level low over northern NSW on Thursday morning. Source: Weatherzone. The movement of the upper-level low over the last two days has also helped draw a fresh pool of moisture-laden air towards southeast Queensland, which is one of the reasons why rainfall intensified so rapidly on Wednesday night into Thursday morning. Troughs and terrain providing triggers When the atmosphere is unstable and loaded with moisture, all that is needed for heavy rain and thunderstorms to occur is a trigger – something that causes air near the surface to start rising. Numerous low pressure troughs sitting near the surface have acted as triggers over the last couple of days. The terrain in southeast Queensland and northeast NSW has also acted as a trigger by forcing winds to rise over the many hills and mountains across the region. Slow-moving systems One other ingredient that has helped make this week’s rain so heavy is the slow-moving nature of the showers and storms. The winds that have been pushing the clouds and rain across southeast Queensland and northeast NSW – known as steering winds – have been relatively weak over the last two days. This has meant that areas of heavy rain have been able to sit over one area for a prolonged period. In some cases, a phenomenon known as ‘training’ has also allowed repetitive areas of heavy rain to track over the same area. Training occurs when multiple storms move over the same location in a sequence, like train carriages moving along a track. The combination of slow-moving storms and training has resulted in some exceptionally large rainfall accumulations over several hours. One rain gauge near Caboolture registered more than 170 mm of rain in three hours on Thursday morning. Rainfall of this intensity can easily overwhelm drainage systems and trigger flash flooding. Beerburrum also received 170.8 mm in the 24 hours ending at 9am on Thursday, which was a new daily record for October at the site. Combining the rain that fell from 9am on Wednesday to 2 pm AEST on Thursday, some areas have received close to 300 mm. This includes preliminary totals of 290 mm at Caboolture Water Treatment Plant and 268 mm at Sheep Station Creek.

21 Oct 2026, 11:34PM UTC

An overnight deluge in South East Queensland and the northeastern corner of New South Wales has intensified during Thursday morning, with flash-flooding occurring in many places. Numerous locations on both sides of the border received more than 100 mm of rainfall in the 24 hours to 9 am local time on Thursday, with several weather stations north of Brisbane receiving well over 200 mm. The highest recorded 24-hour total was a massive 263 mm at the Caboolture Water Treatment Plant, just north of Brisbane. But the unfolding story of this severe weather event is not just the high 24-hour rainfall totals, but the sustained periods of intense rainfall which are continuing well into Thursday. Rainfall intensifies after dawn in heavily populated corner of SE Queensland Image: Radar over SE Qld and NE NSW for the six hours to 8 am (AEST) on Thursday, October 22, 2026. Source: Weatherzone. After steady rain throughout the night, rainfall rates increased dramatically after dawn at many locations in and around Brisbane, especially on the Sunshine Coast. For example: 172 mm was recorded at Caboolture Water Treatment Plant in the 3 hours to 8:30 am. 168 mm was recorded at Sheep Station Creek (Morayfield) in the 3 hours to 7:30 am. 167 mm was recorded at Round Mt Reservoir in the 3 hours to 8:15 am. This is the heaviest October rain in decades in several locations, and some records have already been broken. For example, Beerburrum (at the southern end of Sunshine Coast hinterland) has registered its wettest October day on record with 170.8 mm. The long-term average for the entire month of October is 81.4 mm. And this has not just been a coastal event. The inland city of Toowoomba received 42.6 mm, its highest October daily total in 29 years and almost as much rain in one day as it received in the four very dry months from June to Setpember this year. What is causing the intense rainfall? Image: Estimate of Queensland rainfall in the 24 hours to 9 am Thursday (AEST), based on radar data. Source: Weatherzone. "Abundant atmospheric moisture is interacting with a surface trough and upper-level trough to cause rain across parts of South East Queensland and NE New South Wales," Weatherzone meteorologist Ben Domensino explains. As Domensino outlined earlier this week, two separate streams of moisture-laden air are colliding over eastern Australia this week. One stream is being provided by winds in the middle to upper levels of the atmosphere carrying moisture east all the way from the Indian Ocean. A secondary moisture source is coming from winds flowing onshore from the Coral and Tasman Seas in the lower atmosphere closer to the surface. With abundant atmospheric moisture and a complex system of troughs over Queensland converting that moisture into rain and storms, key ingredients are in place for the current severe rainfall event. How long will this widespread rainfall last? Image: Total accumulated rainfall predicted for Queensland and parts of adjacent states up until next Wednesday, October 28, 2026, according to the ECMWF model. Source: Weatherzone. Weatherzone meteorologist Jess Miskelly says the general setup with the potential for storm and periods of heavy rainfall will persist until next Tuesday. "During this time, peak storm days are likely to be Thursday into Friday and also Monday as surface troughs concentrate over the southeast Queensland region," Miskelly says. "By Thursday, the intensely humid northerly airstream will finally be displaced by a cold front moving in from the west. "The surface high pressure cell over the Tasman Sea will then shift eastward with dry westerly winds to follow and storm activity shifting to northern Queensland." Severe thunderstorms possible during Thursday On Thursday morning, the BoM issued a severe thunderstorm warning for very dangerous thunderstorms that are likely to produce heavy, locally intense rainfall that may lead to dangerous and life-threatening flash flooding over the next several hours. Locations which may be affected include Brisbane, Caboolture, Ipswich, Nambour, Samford and Woodford. During thunderstorms, remember to: Park your car undercover away from trees. Close doors and windows. Keep asthma medications close by. Storms and wind can trigger asthma attacks. Charge mobile phones and power banks in case the power goes out. Put your pets somewhere safe and make sure they can be identified in case they get lost. Do not drive now unless you have to because conditions are dangerous. Tell friends, family and neighbours in the area. Go inside a strong building. Stay inside until the storm has passed. Please check your local SES in Queensland and NSW for emergency information as this dangerous weather event continues to develop, and remember to check the Weatherzone warnings page for the latest weather warnings and flood alerts.