Atmospheric river season is upon us once again. The first major storm of the 2024-2025 water year is coming, and from space it looks like a monster.
The storm currently off the northwest coast of the United States – described by meteorologists as a “bomb cyclone” – is bringing with it an atmospheric river. Strong winds and intense rainfall are expected.
The image below, taken by the National Oceanic and Atmospheric Administration, shows the bombarded cyclone and the atmospheric river beneath it, dumping precipitation on Northern California and surrounding states.
A bomb cyclone is approaching California on Wednesday.
(National Oceanic and Atmospheric Administration)
The last two winters have been unusually wet in California, and while it’s unclear how this season will play out, this first storm certainly gives it an impressive start. This week’s weather event marks the first major atmospheric river in months; the last two water years have seen dozens.
The animation below gives an idea of the storm’s movement, rotating counterclockwise and forming a classic cyclone as a jet of moisture escapes from it onto the west coast.
Seen from space, the storm is enormous and extends across much of the North Pacific Ocean. Wave data showed swells of more than 20 feet in waters off Northern California on Tuesday as winds topped 40 knots.
The exceptionally powerful bomb cyclone is helping to fuel this monster storm, but because it has intensified so far from the coast, its effects are diminished.
Just because it’s officially a bomb cyclone doesn’t mean it’s the worst storm on record, Daniel Swain, a climate scientist at UCLA, said during an online press briefing. “It’s bombing hundreds of miles west of the shore.”
Although dramatic in terms of nomenclature, a bomb cyclone is a low pressure system found north of the tropics and south of the Arctic that deepens or intensifies very quickly over a 24-hour period.
This system produced an effect almost four times greater than that needed to be considered a bomb cyclone, officials said. The strongest winds occurred offshore, but the intense system still brought major winds to the Pacific Northwest and is helping to push the great atmospheric river toward the West Coast.
Bomb cyclone hits west coast on November 20, 2024
(Cooperative Atmospheric Research Institute / National Meteorological Service)
The animation below, from NOAA’s GOES-West satellite, shows the formation of the cyclone and its movement along the coast.
Many areas of Northern California can expect more than six inches of precipitation during the rest of the week, according to the National Weather Service office in Sacramento. In Southern California, light rain is expected this weekend.
Northern California is expected to experience heavy precipitation from the atmospheric river arriving on November 20, 2024.
(National Weather Service, Sacramento)
Some 38,000 Californians were left without power because of the storm, and two people in Washington were killed by falling trees, the Associated Press reported.
Experts are warning of the risk of flooding from heavy rain expected to fall across much of the Pacific Northwest over the coming days.
The Associated Press contributed to this report.
