California Can Blame Its Rain on Low-Pressure Dip Stuck in Sky

Californians can blame the violent, incessant rainstorms hammering their state on an expanse of low pressure that has parked itself high above the northern Pacific, funneling storm after storm ashore.

(Bloomberg) — Californians can blame the violent, incessant rainstorms hammering their state on an expanse of low pressure that has parked itself high above the northern Pacific, funneling storm after storm ashore.

That low-pressure trough is acting like an open door, allowing mild, moist air to flow off the ocean, fueling the gusty rainstorms lashing California. Much to the state’s chagrin, the trough is going to sit stubbornly in place until some other larger meteorological force comes along to shove it out of the way.

“We are likely in this pattern for the next two weeks,” Ryan Truchelut, president of WeatherTiger LLC, said Thursday in an interview. “Poor California will be getting a rain storm every two or three days. From a societal perspective it is too much water, too quickly.”

The so-called atmospheric rivers ushered ashore by the low-pressure trough have already caused flooding in parts of the state, though the deluge is putting a dent on the region’s ongoing drought, which currently covers about 98% of the state, according to the US Drought Monitor. 

While the drenching will help the parched land of the US West, little moisture will cross over the mountains to relieve the drought that grips the Great Plains and parts of the Midwest, according to Truchelut.

As the rain and snow get wrung out across California and the US West, the eastern part of the nation has been relatively mild. New York’s Central Park hit 66F (19C) on Wednesday, tying the daily record for the date set back in 1950.

There are signs the weather could shift by around Jan. 23, said Matt Rogers, president of the Commodity Weather Group LLC. Such a move requires a global wave of thunderstorms and low pressure — known among meteorologists as the Madden-Julian Oscillation — to make its way back to the Indian Ocean, and for global winds to reverse. Without such requirements, it’s quite possible California won’t start drying out until Jan. 30.

If those global winds stick around, “the western waterworks continue,” Rogers said.

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