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Yahoo
a day ago
- Climate
- Yahoo
Forecasters expect an active hurricane season, but history says otherwise
MIAMI - The 2025 hurricane season is off to a busy start in the eastern Pacific, with three tropical cyclones already having developed before a single named system has formed in the Atlantic, which could be an indicator of what lies ahead. Since reliable record-keeping on hurricane seasons began in the late 1960s, there have been less than two dozen years in which three or more named storms developed in the eastern Pacific before the Atlantic recorded its first. This occurrence happens about once every four years and can take place regardless of the status of the El Niño–Southern Oscillation or what is commonly referred to as the ENSO. In more than 84% of the seasons where three or more named storms formed in the eastern Pacific before the Atlantic, the Atlantic basin failed to end the year with more activity than its eastern Pacific counterpart. The only seasons where the Atlantic was able to overtake the Pacific was during a La Niña or a Modoki El Niño cycle – neither of which are in control of weather patterns in 2025. These years were 1998, 2004 and 2010, with only the latest occurrence flipping the script in any meaningful way. Notably, when the eastern Pacific has produced more than four named storms before the Atlantic has even managed one, the Atlantic basin has never gone on to surpass the Pacific in total activity during the season. 2025 Atlantic Hurricane Season Outlook: Here's How Active This Year Could Be Without El Nino, La Nina Patterns Despite the historical precedent over nearly the last 60 years, forecasters at Colorado State University are betting against the odds this year. In the organization's latest outlook for the Atlantic basin, forecasters expect 17 named storms to form, with nine becoming hurricanes and four of those strengthening to major hurricane status – which would be a busier than an average season if the prediction turns out to be accurate. If the outlook holds true, 2025 would be in the running for being the only season with the world in a neutral status of the ENSO where the Atlantic overtakes the eastern Pacific in terms of activity. "The team bases its forecasts on a statistical model, as well as four models that simulate recent history and predictions of the state of the atmosphere during the coming hurricane season," CSU stated in its recent release. FOX Weather Hurricane Specialist Bryan Norcross analyzed the latest outlook from CSU and had some words of caution for those wanting to edge the prediction into stone. "…there is more uncertainty than normal in these numbers because nothing is really pushing the season any which way. All these signals are very weak. When signals are weak, then if something is just teeter tottering, it can tip over, you know. So, we wouldn't be surprised to see this forecast be wrong," Norcross stated. Hurricane Season 2025: Here Are The Names For Storms You'll See This Season Pools of warmer and colder water temperatures across the Pacific and Atlantic will play a major role in shaping what unfolds across both basins during the next five months of the tropical cyclone season. Currently, a neutral signal - commonly referred to as "La Nada"- is in place, which can lead to wide variability in how active the season becomes, but it's the localized pockets of above- or below-normal sea surface temperatures that can make a difference. For instance, in the eastern Pacific, the warmest waters are located along the coasts of Central America and southern Mexico, which has supported the formation of Alvin, Barbara and Cosme, with Dalila and Erick waiting in the wings. These cyclones have not maintained strength for long due to a vast pool of cold water stretching from the Baja Peninsula to Hawaii and extending southward toward the equator. It's this combination of warm and cold pools that has led NOAA and other global agencies to declare that a neutral phase, known as a La Nada, is currently underway. If one of these anomalies gains dominance, either a La Niña or El Niño could emerge, but such a shift is not expected to occur until after the peak of the hurricane season has passed. In the Atlantic, several conflicting pockets of sea surface temperatures are at play - many of which are known to suppress cyclone activity. Forecasters are paying close attention to the Atlantic's Main Development Region, which has generally remained at or just below average, the extremely warm waters of the northern Atlantic and a small but impactful phenomenon called the Atlantic Niña, which tends to reduce sea temperatures near the African coast. As of now, none of these features appear to be producing favorable conditions for enhanced tropical cyclone formation, meaning if there is an error in the tropical seasonal forecasts, it likely leans toward overestimating storm activity versus underestimating. One area of notable concern lies in the exceptionally warm waters of the Gulf and the Caribbean. If a cyclone were to enter these regions, conditions would likely exist for rapid intensification and article source: Forecasters expect an active hurricane season, but history says otherwise
The Guardian
25-05-2025
- Climate
- The Guardian
The floods and droughts in Australia are fingerprints of a warming planet
As New South Wales once again faces heavy rainfall and flooding, the Victorian towns of Euroa and Violet Town will enter stage 2 water restrictions next Wednesday. How is the climate crisis affecting these contrasting extremes? The weather pattern bringing heavy rainfall to NSW is a common wet-weather scenario for the coast. A high-pressure system in the Tasman Sea has stalled, and the anticlockwise air flow around the high is pushing moist air from the ocean over land. At the same time, about three kilometres above the surface, a low-pressure system is lifting the moist ocean air up. As moist air rises, it forms clouds, storms, and finally rain. While this weather pattern itself isn't unusual, the duration of the weather pattern is. Typically, high pressure in the Tasman may hang around for one to two days. But the current high has been there for the past four days, bringing unrelenting rainfall to NSW. The rain is falling on already sodden ground, increasing the likelihood of flooding. Sign up for Guardian Australia's breaking news email This is reminiscent of what we saw during the March 2021 floods. Unfortunately, the forecast for the next few days is also reminiscent of March 2021. After the rain from the east finally moves away, another strong band of rain is forecast to cross NSW from the west on Monday. Scientists are actively researching how climate change is shaping Australia's weather systems. We are not sure if weather systems will stall more often or not, mostly because we don't yet have the computing power to run high-definition climate models needed to study them. However, climate modelling capability is growing every year. Just last week, Australian climate scientists took part in a global hackathon to analyse data produced by models with about 50 times higher resolution than a typical one. Earlier studies using lower definition models suggest we may see a decrease in stalled high pressure in the Tasman Sea, and low-pressure systems may also occur less often but produce more intense rainfall when they do happen. While future high- and low-pressure systems are uncertain, atmospheric moisture is likely to increase in a warmer world. After the March 2021 floods, my colleagues and I assessed how often Sydney may experience persistently high amounts of atmospheric moisture over the region. High atmospheric moisture is a key ingredient in heavy rainfall, and when it sticks around for a while, persistent rainfall and flooding become more likely. We found that by 2080-2100, the chance of these high moisture events may increase by about 80% under both moderate and high emissions scenarios. With more moisture in the atmosphere, when low-pressure systems do occur and help convert the moisture into rain, the rain will probably be more intense due to global heating. As NSW sandbags, Adelaide is ramping up its desalination plant to ensure the city's water supply. Parts of South Australia, Victoria, Tasmania and Western Australia have received very much below the average rainfall over summer and autumn. Drought in Australia is largely driven by a lack of heavy rainfall events. Only one to five days of heavy rainfall per year can be the difference between whether there is a drought or not. The climate patterns in the Indian and Pacific Oceans, which influence year-to-year rainfall variability in Australia, have been in neutral or dry phases. Neither El Niño nor La Niña have appeared since autumn 2024. La Niña tried to rear its head over summer but didn't quite develop. Sign up to Breaking News Australia Get the most important news as it breaks after newsletter promotion The visually spectacular northwest cloudband, which can bring a band of rainfall from Broome to Hobart, has been absent this year. Instead, slow-moving high-pressure systems have brought frustratingly settled weather to southern Australia. Like flooding, the change in drought occurrence with a warming planet is still a leading topic of research in Australia. Since droughts are rare events, identifying trends in the data is much harder than identifying trends in maximum temperature, for example, which happens every day. The 'tinderbox drought' of 2017-2019 was the first drought in Australia where the severity would not have been possible without global heating. Additionally, southwest Australia has seen a robust rainfall decline since the 1970s, which is expected to continue. Droughts and floods have marked the Australian psyche for generations. But the fingerprints of a warming planet are starting to appear as increasing rainfall intensity and drought severity. It is undoubtedly clear that continuing to burn or export fossil fuels will increase the risk of extreme weather devastating Australia. Dr Kimberley Reid is a postdoctoral research fellow in atmospheric sciences at the University of Melbourne
