A powerful bomb cyclone associated with a major atmospheric river is expected to drench the West Coast from Washington to California by midweek, potentially contributing to flooding.
WHAT IS A ‘BOMB CYCLONE’?
The meteorological terms “bombogenesis” or “explosive cyclogenesis” give rise to the name “bomb cyclone.” This occurs when a storm system’s central pressure lowers by at least 24 millibars within 24 hours.
The FOX Forecast Center expects a large stream of moisture to arrive Tuesday night and last through the end of the week, possibly into the weekend.
This system will produce consistent, moderate rain over several days, perhaps flooding roads, minor streams, and even larger rivers.
From Wednesday to Friday, some locations could receive 2–4 inches of rain every day, with higher amounts likely in the Highlands.
Strong gusts will also begin to blow in Tuesday evening as the storm approaches. The FOX Forecast Center predicts gusts of 60–70 mph in exposed locations, such as mountains, headlands, and parts of the coastal plains.
As with other atmospheric rivers, this one will dump feet of snow in the Cascades and Sierra Nevada. Strong winds will bring in milder Pacific air, raising snow levels higher than typical.
The entire Cascades region is under a blizzard warning from late Tuesday afternoon to Wednesday AM. This is where severe winds are most likely to combine with snow, reducing visibility to a quarter-mile or less for at least three hours.
WHAT IS A BLIZZARD?
Snow will most certainly start about 3,500 feet, with the highest quantities above 4,000 feet, covering mountain ranges with several feet of snow.