A strong jet stream currently racing over the Northeast is a key ingredient that is leading to the rapid development of a bomb cyclone eyeing France, Ireland and the United Kingdom with damaging wind gusts and torrential rain.
Wind speeds in the upper atmosphere across Maine reached over 200 mph Tuesday, fueled by a large change in temperature over the eastern U.S. A weather balloon launched from Caribou, Maine, Monday night recorded 206-mph winds around 30,000 feet.
Pilots in the region took advantage of the robust tailwind. The FOX Forecast Center found Air France Flight 79, heading from Los Angeles to Paris Tuesday morning, received a 200-mph boost in ground speed by flying into the heart of the jet stream, moving at 768 mph relative to the ground. The flight would normally expect a ground speed of around 559 mph.
Another flight that left Los Angeles bound for London Tuesday night managed to reach 784 mph relative to the ground while over the Atlantic thanks to catching a ride on the jet stream.
Jet streams are narrow bands of strong wind in the upper levels of the atmosphere and follow the boundaries between hot and cold air, according to the National Weather Service. And since that boundary is more pronounced during the winter months, the jet stream is stronger during the winter.
But the jet stream is turning from aviation quirk into fueling a dangerous bomb cyclone quickly developing across the Atlantic Ocean, becoming what the U.K. Met Office is naming Storm Ciarán. The storm remains on track to impact northern Europe through Thursday.
"It's this jet stream barreling out of North America that will pick up Storm Ciarán and intensify it," the U.K. Met Office’s Alex Deakin said in a weather briefing posted on X. "And particularly as we go through Tuesday night and into Wednesday, the storm system crosses the jet stream, and that’s when it really intensifies."
- Image 1 of 9
- Image 2 of 9
- Image 3 of 9
- Image 4 of 9
- Image 5 of 9
- Image 6 of 9
- Image 7 of 9
- Image 8 of 9
- Image 9 of 9
Ciaran's strengthening was already underway Wednesday morning, with the storm's central pressure dropping 17 millibars in 12 hours. Computer forecast models show the storm "bombing out" from about 989 millibars early Wednesday morning to about 952 millibars by early Thursday morning as it approaches Ireland and the U.K. – well within the criteria for a "bomb cyclone," which is a pressure drop of at least 24 millibars within 24 hours.
Amsterdam's Schiphol Airport already announced reduced capacity for the runway due to rough weather Thursday and Friday. KLM started canceling flights in and out.
With the storm center forecast to head up along the English Channel and into southern England late Wednesday into Thursday, High Wind Warnings are in effect across the southern coasts of England, northern areas of France and the western coast of Wales. Predicted gusts are up to 80 to 100 mph along France’s north coasts, 70 to 85 mph along the English Channel and some 65- to 75-mph gusts inland in southwestern England and northern France.
"Very strong northwesterly winds associated with Storm Ciarán could disrupt travel, utilities and may cause some structural damage," the U.K. Met Office warned in its wind alerts.
Point St. Mathieu in Northwest France clocked a wind speed of 91 mph as the monster storm approached. The wind already whipped up impressive waves in France.
In addition, heavy rain is forecast across the southern U.K., Ireland and northern France, leading to flash flood worries and rough surf with large seas forecast for the coasts of France.
Ciarán will be a slow-moving storm with impacts lingering into Thursday, followed by calming wind and rain, though unsettled conditions will remain through the end of the week.
Earlier storm slams Northern Ireland
For some parts of the UK, Ciaran is no rest for the weary. Another potent storm struck Northern Ireland earlier in the week, dropping torrential rain and flooding the town of Newry.
From the Monday evening through Wednesday afternoon, Northern Ireland Fire and Rescue received 384 emergency calls.
Crews rescued five people who waded into the water, 31 people trapped in vehicles and evacuated 12 more from homes ahead of Storm Ciaran.