Whoever said it never rains in Southern California is not exactly right, as the Golden State is in for some rare June rain this week.
“We have rain and thunderstorms that are hitting parts of California,” said FOX Weather meteorologist Britta Merwin. “This is a rare wet stretch of weather in what should be the beginning of their dry season. So, we have this dip in the jet stream that’s allowing for moisture to really move in and a little bit of lift, and there you have it. You get showers and you get thunderstorms.”
238-MPH JET STREAM SHAVES AN HOUR OFF CROSS-COUNTRY FLIGHTS TO EAST COAST
That dip in the jet stream is anchoring an upper-level low, think a chunk of atmospheric energy, off the coast of Central and Southern California. All it takes for showers and thunderstorms is a little heat of the day from the sun, and up pops thunderstorms which can drop a lot of rain in little time, along with hail.
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Early Tuesday morning, ping-pong-ball-size hail fell in Kern County in the Central Valley.
“I will let you know that when we do see severe weather in California, it’s always with an upper-level low,” Merwin said. “It’s not typical for the month of June, but to be quite honest, we usually don’t have an upper-level low sitting over California in June. So, if we do see severe weather, you know, some gusty winds, maybe some small hail, you would expect that to happen with an upper-level low.”
Up to 2 inches of rain could fall in some mountain areas. Most of the state could see a quarter to a half inch with a storm overhead. It doesn’t sound like much but looking at San Francisco, that would be 2-4 times the rain the city normally sees in the month. Almost 90% of the yearly rainfall in San Francisco is over five months of the year. The dry season is May through October with average rainfall bottoming out in June, July and August, which is why this rain would be so rare.
This pattern due to the Mediterranean climate that most of the state experiences.
The low slowly drifts inland through the workweek. That will push thunderstorms east each day. Thursday and Friday will be California’s driest days as storms move across Nevada. With the weekend, however, comes another upper-level low that drops down the coast and brings another chance of storms.
If you are wondering why so many rare rain chances are happening in June, blame it on an omega block. A large and very stubborn high-pressure center has set up over the center of the country. The jet stream dips over the West and East coasts. Storms and upper-level lows ride along the jet stream and over the west coast.
The jet stream looks like the Greek letter omega (Ω), so meteorologists call this an omega block.
Omega blocks are usually large, which means they are one of the more stubborn blocks to break down. This can create concerns for flooding where the wet weather persists and drought worries where the dry weather happens.