Hurricane Lorenzo, the weirdest storm of the Atlantic hurricane season, struck the Azores on Wednesday and is forecast to continue its jaunt across the eastern Atlantic toward Ireland. It could make a rare landfall there with hurricane-force winds and crippling surf.
The freak hurricane rapidly intensified into a Category 5 monster over the weekend, setting a record as the strongest hurricane to ever form that far north or east in the Atlantic basin. It has since dwindled back down to a solid Category 1 storm, and it hit the westernmost Azores islands on Wednesday with winds of up to 145km/h.
Rain and pounding surf also affected the islands with the local weather agency warning that waves could swell as high as 21.34m. The storm has reportedly caused power outages on a number of the islands as well.
All told, Lorenzo marks the fifteenth tropical cyclone (the generic name from tropical storms and hurricanes) to come within 370 nautical kilometres of the Azores since the 1840s, according to a database kept by the U.S. National Oceanic and Atmospheric Administration. The last to brush the island chain was 2016's Alex, which passed by as a tropical storm. With winds of up to 145km/h, Lorenzo is among the strongest storms on record to pass over the islands.
The National Hurricane Centre expects Lorenzo to transition to an extratropical cyclone with hurricane-force winds in the next day or so. Extratropical cyclones are one of the many flavours of swirling storms. What differentiates them from the tropical variety is that extratropical cyclones have cold air at their core (tropical cyclones have a warm core). They also tend to latch onto other weather patterns as they head poleward.
In Lorenzo’s case, it will latch onto the jet stream in the coming days, which will accelerate its migration to the east. It’s expected to slam into Ireland by early Friday with powerful winds of up to 128km/h and what Met Éireann, the Irish weather service, calls “squally rain.” Most trees still have their leaves, and soil is saturated from recent rains, which the agency said could lead to downed branches and trees. In addition, Met Éireann is also calling for waves of up to 12 metres to hammer the coast.
If this whole thing sounds eerily familiar, may I point you to 2017's Hurricane Ophelia. That storm reached Category 3 status, and until Lorenzo, it held the title of the fiercest northerly hurricane. It also plowed into Ireland, leaving more than 120,000 people without power and generally wreaking havoc.
There are ample lines of evidence that Hurricane Lorenzo fits with patterns scientists are seeing when it comes to climate change. Research indicates that climate change is shifting the latitude where hurricanes intensify the most northward. Warmer than normal ocean temperatures — a hallmark of climate change — have helped feed Lorenzo.
The waters around the Azores are up to 3 degrees Celsius warmer than normal for this time of year. In absolute terms, they’re around 25 degrees Celsius, which isn’t necessarily warm enough for a hurricane to intensify but is enough to keep it going as it chugs further north and becomes extratropical.
Oh, speaking of which, recent research shows climate change could increase the odds of extratropical cyclones with heavy precipitation over North America and Europe threefold by the end of the century.