Atmospheric river will blast California with heavy rain and snow ‘measured in feet’

[_Keith]

Atmospheric river will blast California with heavy rain and snow ‘measured in feet’

 

 

 

 

By Angela Fritz January 3 at 2:45 PM 

 

A river of atmospheric moisture will flow over California through the weekend. (pivotalweather.com)

California is getting the rain and snow it needs this week thanks to a shift in the weather, and the region’s meteorologists are finally calling it “normal” for winter on the West Coast. Through the weekend, up to two feet of water could rain down on the high elevations of the Golden State. If the majority of that moisture falls as snow, it could mean over 10 feet of snow along the Sierra Nevada peaks.

The ridge of high pressure that has been in place for days is moving east, and a strong low pressure system that formed in the Gulf of Alaska is taking its place. As winds flow counterclockwise around the low, they pull tropical moisture northeast from the Pacific Ocean — an atmospheric river that will pour down over much of California in the coming days.

Rain and snow will be heavy at times, especially in the northern Sierra Mountains, where winds from the west will be forced to flow over high terrain. As air rises, the water vapor (humidity) will condense into clouds and precipitation.

The National Weather Service is suggesting two feet of precipitation in the form of water could drench Northern California. In the cold high elevations, much of that will be frozen, which means multiple feet of snow.

(National Weather Service)

Snow levels are starting low — just 2,000-3,000 feet, according to the National Weather Service — but will rise as the air gets warmer later this week. Nearly three feet had already accumulated at Kingvale, Calif., (elevation 6,000 feet) as of Tuesday morning.

https://twitter.com/NWSSacramento/status/816317814621478912

“Three to four feet of snowfall accumulation can be expected above 4,500 feet with some areas possibly seeing 5 feet or more along the crest by Thursday,” the Weather Service wrote in a Tuesday morning discussion. “Needless to say, severe travel impacts are likely crossing the northern Sierra.”

Travel is being discouraged in the northern Sierras until the storm lets up. Road closures for major thoroughfares, such as Interstate 80 and Route 50, are possible over the passes during the heaviest snowfall through Wednesday.

View image on Twitter

 

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NWS Sacramento 

 

✔@NWSSacramento

Have travel plans across the mountains? You'll want to postpone a few days if you can! Here's a look at I-80. Expect very long delays #cawx

9:56 AM - 3 Jan 2017

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By the weekend, the atmospheric river will shift south and bring rain to Southern California, a region that has been neglected by rain over the past year. While a large portion (around 15 percent) of Northern California saw drought relief in 2016, the southern half of the state was very dry up until December.

“Los Angeles marked a sober milestone last year, when the NWS announced that the last five years were the driest ever documented in downtown L.A. since official record-keeping began almost 140 years ago,” wrote Angel Jennings in the L.A. Times Monday evening. The L.A. Times has provided unparalleled coverage of the region’s historic drought since it began in 2011. “Precipitation during that period totaled just 38.79 inches — roughly half of the normal amount.”

Then, in a marked reversal, December turned out to be the wettest since 2010, and it looks like the pattern will stay wet through at least the beginning of next week. A few tenths of an inch of rain will fall across Southwest California through Friday, followed by a significant surge over the weekend.

More than five feet of snow and up t 8 inches of rain could fall in parts of California through Monday. (pivotalweather.com)

The National Weather Service in Los Angeles is cautioning that they do not know exactly where the heaviest rainfall will occur, but that “there is potential for a heavy rain event across portions of all of Southwest California sometime between Saturday and Monday, which could result in significant flash flooding with mud and debris flow issues, especially across the recent burn areas.”

 

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Daniel Swain 

 

✔@Weather_West

Appears that two major #AtmosphericRiver events will occur over next 7d. Second one on Sat looks especially powerful. Sig. flood risk. #CAwx

12:07 PM - 3 Jan 2017

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Even with all the travel headaches and flooding these storms will likely cause, Californians are welcoming the precipitation after years of drought and water restrictions.

“This is what we’re supposed to be getting,” Johnnie Powell, a meteorologist at the National Weather Service, told the L.A. Times. “After six years of a drought, I love saying that. This is normal rain and snow that we’re supposed to be getting in December and January.”

 

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Angela Fritz is an atmospheric scientist and The Post's deputy weather editor. She has a B.S. in meteorology and an M.S. in earth and atmospheric science.

  Follow @angelafritz

[Hammer]

Woo hoooo!

[Funkthulhu]

Man, that is the click-baitiest weather headline I've seen in a while...

 

Click hear to learn how ice works

10 secrets to give you rock hard ab-normal weather

You won't believe how big this hail was

[Yunder Wækraus]

Scary stuff. My mom lives 80 miles from the coast, but she's at only 3' above sea level and a block from a levee :-( This is possibly a worst-case scenario: massive amounts of rain coupled with snow that is melted by warmer rain within the same week. If they get a warm spell in the mountains, we might see a catastrophic flood in the Valley again.

[NorCalKing]

They seemed to have toned down ever so slightly the severity this AR. But having said that, I'm keeping a close eye on this one, as it will be a Nor Cal event for the most part. Guess the drought will have a serious dent put into it after this year.

[GottmitAlex]

Calling for mid to upper 20's tonight for Sacramento Area.

Stay warm folks.

[NorCalKing]

1 hour ago, GottmitAlex said:

Calling for mid to upper 20's tonight for Sacramento Area.

Stay warm folks.

Yep. Looks like this is the last really cold night for a while here in NorCal. The 10 day doesn't show any days below freezing.

[Funkthulhu]

12 hours ago, Yunder Wækraus said:

Scary stuff. My mom lives 80 miles from the coast, but she's at only 3' above sea level and a block from a levee :-( This is possibly a worst-case scenario: massive amounts of rain coupled with snow that is melted by warmer rain within the same week. If they get a warm spell in the mountains, we might see a catastrophic flood in the Valley again.

Wow, those sound like Louisiana numbers! 

[WestCoastGal]

It's 11pm and here comes the rain. It moved in fairly quickly into our area about 20 minutes ago. Wunderground shows it from the border of Oregon all the way south not quite to San Diego. Amazing. 

 

[Yunder Wækraus]

20 hours ago, Funkthulhu said:

Wow, those sound like Louisiana numbers! 

Yep :-( on the north side of town, the water behind the levee looks to rest (in drought!) 10' above surrounding houses. The San Joaquin Delta communities are truly the equivalent of Louisiana, and no one knows it.

[Yunder Wækraus]

http://www.recordnet.com/news/20170105/flooding-its-happened-before/1

[NorCalKing]

Strangely enough, it's actually sunny here for the last hour. Calm before the storm, I guess.

[Panamajack]

So here in coastal L.A., yesterday, Sunday, was 75 degrees and sunny (while NorCal was getting slammed with rain and snow). We then got rain overnight into Monday, but nothing compared to NorCal. Today it misted in the morning then the sun came out and it was 65 degrees until at about 3pm when the clouds started moving in. It is currently cloudy and 60.  There are two more systems that will drench NorCal but will not do much to coastal SoCal, I think I'll have to water my water loving palms like Kings and Pygmys since the rain won't do much. Friday temperatures are going to climb to 70 and it'll be sunny for the rest of next week, with highs in the upper 60s and lows in the mid 50s. 

Edited January 10, 2017 by Panamajack

[NorCalKing]

1 hour ago, Panamajack said:

So here in coastal L.A., yesterday, Sunday, was 75 degrees and sunny (while NorCal was getting slammed with rain and snow). We then got rain overnight into Monday, but nothing compared to NorCal. Today it misted in the morning then the sun came out and it was 65 degrees until at about 3pm when the clouds started moving in. It is currently cloudy and 60.  There are two more systems that will drench NorCal but will not do much to coastal SoCal, I think I'll have to water my water loving palms like Kings and Pygmys since the rain won't do much. Friday temperatures are going to climb to 70 and it'll be sunny for the rest of next week, with highs in the upper 60s and lows in the mid 50s. 

The only snow in bay area NorCal was in the mountains (which many SoCal Mountains in the Sierra also received) in fact snow levels were actually above 9000 ft yesterday with temps in the upper 60's. Be thankful NorCal is getting the rains, or our friends down south would be in a heap of trouble without that rain.

[GottmitAlex]

19 minutes ago, NorCalKing said:

The only snow in bay area NorCal was in the mountains (which many SoCal Mountains in the Sierra also received) in fact snow levels were actually above 9000 ft yesterday with temps in the upper 60's. Be thankful NorCal is getting the rains, or our friends down south would be in a heap of trouble without that rain.

Hear, hear!

[Panamajack]

1 hour ago, NorCalKing said:

The only snow in bay area NorCal was in the mountains (which many SoCal Mountains in the Sierra also received) in fact snow levels were actually above 9000 ft yesterday with temps in the upper 60's. Be thankful NorCal is getting the rains, or our friends down south would be in a heap of trouble without that rain.

Yes, I know. Thanks. I'm thankful it is raining in all of California, because without it, we'd all be in trouble. 

[NorCalKing]

Exactly. 

[DoomsDave]

On 1/7/2017, 3:17:42, Yunder Wækraus said:

Yep :-( on the north side of town, the water behind the levee looks to rest (in drought!) 10' above surrounding houses. The San Joaquin Delta communities are truly the equivalent of Louisiana, and no one knows it.

They even have rice paddies there, from what I've heard.

[DoomsDave]

16 hours ago, NorCalKing said:

The only snow in bay area NorCal was in the mountains (which many SoCal Mountains in the Sierra also received) in fact snow levels were actually above 9000 ft yesterday with temps in the upper 60's. Be thankful NorCal is getting the rains, or our friends down south would be in a heap of trouble without that rain.

Burning candles to Mr. Mulholland . . . .

This has been a happy holiday season. Over the past three weeks or so, I've had the better part of 12" (32 cm) of rain. That's more than we got for an entire two years running at least. Maybe three. Driving home through the hills of Eire on the way home from the Dark Tower.