An atmospheric river – a stream of moisture, similar to a river, that flows into the Pacific Ocean and brings extreme rains – is causing flooding with up to a foot of rain and several meters of snow on the West Coast.
San Francisco has received more than 2 inches of rain with this system.
“Models indicate that an atmospheric river event will strengthen during the early morning hours, leading to heavy rainfall,” the Weather Prediction Center said.
It seems likely that the most steady and highest rainfall will be concentrated along the Big Sur coast throughout the afternoon and evening, according to the National Weather Service office in San Francisco.
“Isolation amounts of 10-12 inches are possible for higher peaks,” said the San Francisco office.
A Level 3 out of 4 threat to extreme rainfall applies to the area on Monday. The system will continue to move down the coast on Monday night.
This storm could reduce rainfall by 2 to 3 inches downtown, the most rainfall the city has seen in about a year. The last time the office recorded a total of more than one inch of storms was in January.
“Heavy mountain snow and lowland rain will spread across California and the Great Basin today and Tuesday,” WPC wrote on Twitter. “There is a high likelihood of heavy snowfall over much of the terrain, accumulating up to 6 feet or more in parts of the Sierra Nevada. Mountain travel may become impossible.”
Mount Shasta reported more than a meter of snow on Monday morning.
Snow in the Sierra could fall at a rate of 3 inches an hour or more between tonight and early Tuesday. This extreme snow, combined with strong winds – gusts of 40 to 60 mph and 100 to 120 mph for the exposed Sierra ridges – will create whiteness and potentially road closures highway, Reno, Nevada, the weather services office said.
Wind advisories are in effect for much of California, western Arizona, Nevada, southern Oregon, and southwestern Idaho. A high wind warning is in effect for the Southern Coast Range, the Horizontal Range and Peninsular Range of California, the Sierra Nevada of Nevada and the Wyoming Basin.
Some of these thick bands of snow can be powerful enough to produce thunder, the Reno office adds.
“Heavy snowfall will be an extended event over the Cascades, Sierra Nevada and Northern Rockies,” the Weather Prediction Center said.
Snow won’t just be for the higher altitudes. The Pacific Northwest and Northern California will see cooler air moving in over the next day.
“Snow levels will drop to sea level over parts of the Pacific Northwest and to the surface of parts of Northern California from Monday night through Tuesday morning,” the forecast center said.
The energy from this system will eventually move into the central US over the weekend, potentially bringing rain to areas that have recently suffered from devastating tornadoes.
Deadly tornadoes at night
Stories of survival and heroes are emerging from the rubble of this weekend’s deadly tornadoes.
“It all happened so fast,” Kyanna Parsons-Perez told CNN, describing the devastating devastation after a tornado hit a candle factory in Mayfield, Kentucky. “We were all just rocking back and forth, and then boom, everything was on us.”
December is sweltering
Warmer temperatures are blanketing the eastern half of the country. In fact, it might sound more like ‘hotter weather’ instead of ‘sweater weather’ in some parts of the central US. High temperatures can soar 20 to 40 degrees above average on Tuesday and Wednesday afternoons. More temperature records are expected to be broken across the Delta.
Temperatures cooled again in the central US on Thursday as a storm system in the West pushed through and milder weather slid into the East Coast.
Milder temperatures could make this week’s stargazing more enjoyable.
One of the best showers of the year
If you stay up all night, Geminids will light up the night sky from Monday night to Tuesday morning.
NASA calls this meteor shower “one of the best and most reliable meteor showers” because the meteors are bright, fast, and numerous.
Your Chances of a White Christmas
Don’t blame the meteorologist. Blaming the Grinch is also known as climate change, but the probability of a white Christmas has dropped for many.
