If you caught the Sunday Night Football matchup between the 49ners and Colts, you may have heard Al Michaels say the terms ‘bomb cyclone’ and ‘atmospheric river’. Both of which are actual weather phenomena, and both were part of the reason Jimmy Garoppolo looked like he was playing with his eyes closed.
Soaking rains for the Pacific Northwest came over the past few days from a powerful, large area of low pressure that underwent bombogensis. Bombogensis is when an area of low pressure quickly strengthens and drops 24-milibars of pressure in 24-hours. It’s essentially the non-tropical equivalent of rapid intensification, which you hear us talk plenty about during hurricane season.
Often times when a large storm system impacts the Pacific Northwest, it’s accompanied by an atmospheric river. This is the “tail” of the low pressure system, the elongated front that tends to stretch all the way to the moist, tropical air of the Hawaiian Islands. Atmospheric Rivers are also referred to as a Pineapple Express, where a firehouse of soaking rain sets aim at the west coast.
Big time drought conditions still prevail for the west coast, but the past few days of soaking rain have alleviated some of that stress. And across Hampton Roads, our abnormally dry conditions got some relief with last night’s cold front.
About half an inch of rain fell with the passage of the front late last night, with more on the horizon. A good shot of rain, and even a few thunderstorms, is likely to move in from the south on Friday.
Meteorologist Steve Fundaro