An ‘abnormal,’ monsoon-like weather pattern hits Southern California, unleashing winds that blast over the Sierra peaks and dumping rain on the valleys.
The system will continue over the central and southern United States for several more days with a 50-60% chance of developing into a severe weather storm.
The National Weather Service warns that heavy rain and a high risk for flash flooding are expected to hit the region across a broad area from the Mojave Desert into the northern Great Basin and the southern portion of California.
Forecasters are predicting a 50 percent chance of a severe weather storm will develop and intensify Sunday night into Sunday afternoon in the southern and central deserts as a combination of a dry airmass and a strong wind system sweeps into the region. It will eventually become a severe weather storm with 100 mph winds by this afternoon.
Flash flooding of river and creeks, high winds, and heavy rain is likely.
The National Weather Service, in a Facebook Live blog, says the moisture will begin to mix north of the Sierra with the cold air mass that’s been lingering over the northern Great Basin and the Coast Range.
The dry air mass will make for an atmospheric conditions in the western United States that should make for more reliable fire weather for early December.
“This is the first time I’ve seen such a pattern in 50 years, so it’s rare,” said weathercaster Nate Olson.
“Once it begins to develop and intensify, it’ll push up through the Sierra and into the Coast Range.”
The dry air will make Sunday’s rain accumulation rates of 10 to 15 inches possible in the valleys, according to the weather service.
The dry air mass will persist for another day in the valley, but the winds will change.
“We’re looking at winds around 60 to 70 mph at low levels in the foothills and valleys through the morning, and then winds will start to pick up into the 100s by midday,” Olson said. “We’ll start to see some light fog and rain in the evening.”
A cold front is expected to move through the area tomorrow.
“The front will make its way through the region today,” Olson said. “Winds then will increase, especially in