Atmospheric River deluges California and the Southwest

By: Dr. Jeff Masters , 3:25 PM GMT on December 22, 2010

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An “Atmospheric River” of extremely moist air continues to affect the Southwest U.S. today, and flooding rains of 1 – 2” with isolated amounts of 2 – 4” can be expected across Southern California, western and central Arizona, southeastern Nevada, and southwestern Utah. The heaviest rains will fall over the coastal mountains south of Los Angeles. The storm began on Friday night, and has brought some rather remarkable rains and snows to the Southwest. Crestline, California, in the mountains just east of Los Angeles, has received 20.05” of rain since Friday. The Sierra Mountains near Sequoia National Park received an astonishing 17 feet of snow at Pescoes since Friday night. Other heavy snow amounts from the storm include 6.4' at Heavenly near Lake Tahoe, 6.5' in Crested Butte, Colorado, and 9 – 13.5' in Mammoth in the Sierras. Some other rainfall amounts from NOAA's latest Storm Summary:

...ARIZONA...
Iron Spring 11.14"
Black Rock 9.23"
Kingman 3.86"
Grand Canyon West 3.15"

...CALIFORNIA...
Crestline 20.05"
Nature Point 18.60"
Tanback 16.94"
Mammoth Lakes 12.82"
Santa Barbara 12.39"
Los Angeles-USC 6.66"
San Diego 4.22"
San Francisco Airport 2.44"

...NEVADA...
Mount Charleston 12.66"
Las Vegas, 24 miles WNW 8.99"
Reno 2.59"

...UTAH...
Gutz Peak 15.90"
Little Grassy 15.10"
Zion National Park 6.76"


Figure 1. The total amount of rainfall one could get if all the moisture in the air were condensed and fell out as rain is called the Total Precipitable Water (TPW). Here, TPW values from microwave satellite measurements are plotted, and show a plume of very moist air connecting the subtropics near Hawaii with Southern California. TPW vales in excess of 20 mm (about 0.8 inches, blue and warmer colors) are often associated with heavy rainfall events capable of causing flooding. Image credit: University of Wisconsin CIMSS.

“Atmospheric Rivers” was a term coined in the 1990s to describe plumes of moisture that ride up out of the subtropics into the mid-latitudes along the axis of a cold front. Traditional water vapor satellite imagery does not show these plumes very well, and it was only when microwave satellite imagery from polar orbiting satellites became available in the late 1990s that the full importance of these Atmospheric Rivers came to be revealed. Atmospheric Rivers account for a significant portion of California's cold season rainfall and snowfall, and an entire session was devoted to them at last week's American Geophysical Union (AGU) meeting in San Francisco, the world's largest Earth Science meeting.

Jeff Masters

High water/flooding (meto234)
The Virgin and Santa Clara rivers are topping out at flood stage at St. George, Utah. Been raining for 3 days and more on the way.
High water/flooding
Desert Rainbow (multex)
desert rainbow
Desert Rainbow
None Shall Pass (DancinPants)
That right there between me and the guy on the far side is the road....and the only one that, as far as I'm aware leads out of Pamo Valley. So he might be stuck there. I drove across there just yesterday!
None Shall Pass

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Quoting pottery:

I thought an hour would be enough....
Can I come out and play now?

(Gee. You are a Hard Old Geezer)

((watch out. You may get reported again, too LOL)


ROFL
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Quoting Grothar:


I forgot what I wanted to say......it happens.


>.
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Quoting presslord:


I thought you were instructed to shut up ; )

I thought an hour would be enough....
Can I come out and play now?

(Gee. You are a Hard Old Geezer)

((watch out. You may get reported again, too LOL)
Member Since: Posts: Comments:
Quoting tinkahbell:
So....do I pack Xanax for a lonnnnnng visit with my parents over the holiday or no? This snow thing is messing with me! They're in Delaware at the beach and we all know what happens in Delaware when it snows A LOT....anyone??


you can NEVER have too much Xanax
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Quoting tinkahbell:
So....do I pack Xanax for a lonnnnnng visit with my parents over the holiday or no? This snow thing is messing with me! They're in Delaware at the beach and we all know what happens in Delaware when it snows A LOT....anyone??


Wouldnt hurt.. lol I would just to be safe.. Its still hard to say at the moment..
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Quoting pottery:

Ahem on your dress ...?
Hems do that. Fall apart. Often from spending too much time on your knees...


I thought you were instructed to shut up ; )
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Quoting presslord:


ahem...

Ahem on your dress ...?
Hems do that. Fall apart. Often from spending too much time on your knees...
Member Since: Posts: Comments:
So....do I pack Xanax for a lonnnnnng visit with my parents over the holiday or no? This snow thing is messing with me! They're in Delaware at the beach and we all know what happens in Delaware when it snows A LOT....anyone??
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Quoting DoverWxwatchter:


That really is interesting. Accumulating snows far south. And anytime over a foot falls in the Carolinas outside the mountains is impressive. See how it pans out.


ahem...
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Quoting Grothar:


I forgot what I wanted to say......it happens.


Happens with people as old as you are LOL
Member Since: October 8, 2008 Posts: 14 Comments: 4553
hmmm.. The new OOZ runs are going to start or running.. Should be up soon.. See if GFS changed or not..
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Quoting caneswatch:


What's that supposed to mean?


I forgot what I wanted to say......it happens.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting Grothar:
<.


What's that supposed to mean?
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Quoting Skyepony:
Firefighters Rescuing Guests from Flooded Mission Valley Hotel

51 guests were trapped in a San Diego hotel. The Premiere Hotel, located at Hotel Circle in Mission Valley, was swamped by flood waters as torrential rain continues to pound San Diego. During the last seven days, the San Diego area has been getting between 3 1/2 and 8 1/2 inches of rainfall. (NOAA Updates: San Diego area floods and warnings)

Firefighters are rescuing the hotel guests as quickly as is safely possible.


Another sad story :(

2Firefighters

2 firefighters died and 17 others are injured.. wow!
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<.
Member Since: July 17, 2009 Posts: 71 Comments: 27208
Quoting HurricaneSwirl:
Wow, look at Frank Strait's preliminary forecast map he just released: (he's the Accuweather meteorologist for the southern states)

Link

I'm right on the edge of 6-12 inches here in Macon. I just can't see that materializing but I'll wait and see :)

Their bread and butter is hype. They have snow all the way to N Central Fl.
Member Since: June 21, 2007 Posts: 10 Comments: 1657
Quoting FLPandhandleJG:
Here's Accuweather predicted snow results..
Interesting..

Quoting HurricaneSwirl:
Wow, look at Frank Strait's preliminary forecast map he just released: (he's the Accuweather meteorologist for the southern states)

Link

I'm right on the edge of 6-12 inches here in Macon. I just can't see that materializing but I'll wait and see :)


nice.. Just posted the graphic.. Like i said I might c a dusting if that.. Unless this L comes through like the most models have been saying the last few days.. We shall c..
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422. Skyepony (Mod)
Firefighters Rescuing Guests from Flooded Mission Valley Hotel

51 guests were trapped in a San Diego hotel. The Premiere Hotel, located at Hotel Circle in Mission Valley, was swamped by flood waters as torrential rain continues to pound San Diego. During the last seven days, the San Diego area has been getting between 3 1/2 and 8 1/2 inches of rainfall. (NOAA Updates: San Diego area floods and warnings)

Firefighters are rescuing the hotel guests as quickly as is safely possible.
Member Since: Posts: Comments:
Here's Accuweather predicted snow results..
Interesting..

Member Since: Posts: Comments:
Wow, look at Frank Strait's preliminary forecast map he just released: (he's the Accuweather meteorologist for the southern states)

Link

I'm right on the edge of 6-12 inches here in Macon. I just can't see that materializing but I'll wait and see :)
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Member Since: Posts: Comments:
418. Skyepony (Mod)
Check out the CIMSS satellite blog. This is just one of many images from that huge explosion the other day from thieves tapping the oil pipeline near Mexico City. Ridiculous explosion last I saw 32 died & a bunch were missing. Well they saw it on satellite, at 1st they thought it might be the local volcano, but that was suspect as it looked nothing like volcanic activity, then matched it time & place to the incident.
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Whaaaaaa...They took Phil Hendrie off my local radio station.
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Quoting Jeff9641:
Qualcomm stadium in San Diego is flooded. Infact all the parking lots around the stadium looks like a lake right now. Just saw this on ESPN.


Odd. I'm on the same channel and I missed it, I guess.

For the 2008 Miami-FSU game, it was raining the entire day and after the game the parking lot was flooded with a half-foot of water.
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Quoting FLPandhandleJG:


Haha.. I am young.. lol I just dont believe everyone is perfect for every second they live in there life.. Just saying!

That's true!
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Quoting HurricaneSwirl:


Yeah, southern snow must be such a pain to forecast >.< And I can imagine the bashing a forecaster will get if they say snow in the south and no snow materializes.


That happens here in Central NC a lot, particularly because the piedmont/coastal plain division usually causes a wide variety of frozen precip types within a narrow band of real estate. So a lot of people hear 'snow' when what they should have heard was 'sleet', etc. The other problem occurs when what's predicted falls as something else.
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Quoting pottery:

You must be too young to remember Cassius Clay, Bobby Charlton, Raquel Welsh, Barbie Benton...
Them, and some others, achieved Perfection in one way or another at points in their time....

just sayin'


Haha.. I am young.. lol I just dont believe everyone is perfect for every second they live in there life.. Just saying!
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Quoting HurricaneSwirl:


Yeah I hope so too, especially you guys in the panhandle that would be a real treat. In the map you posted on 373 we are barely in the C section, which shows some pretty good chances but we are supposed to be at 52 for the high that day.. A little high for a snow day. Then again, are NWS is for some reason 10 degrees warmer than the others, as evident by columbus's high being 10 degrees higher than auburn's when they are right next to each other XD


Yeah just depends on how fast this systems comes in and when the cold air decides to come too.. Timing is everything but might have to change a few things if the L comes in faster then expected.. I have a feeling that it might slow down when it crosses LA.. But thats my opinion and all.. But need too look at other maps of the possibility.. But right now its hard to predict it this down south.. If the L comes in slow like some models have been running the last few runs then we could have a big mess.. I would say the L needs to slow down and arrive on sunday to make a lot of ppl happy but I just dont think the cold will catch up on christmas day.. Looks like the cold plunge will start coming in good on Sunday.. But if not some ppl will see some snow and probably up the carolina coast into New England most likely..

Still some questions out there but its not that far away tho.. should be interesting to watch tho and maybe the system after this needs to be bare watching..
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Quoting HurricaneSwirl:


Yeah I realize that, but the fact that TWC is predicting rain instead of snow shows what I posted, that it doesn't think it will get cold enough to snow, whether it be on the surface or not. Other sites do, but barely. I'm just hoping they are being conservative until the event gets closer.


I would wager that forecast has less to do with the actual air temperature and more to do with lack of cold mid-level temperatures.
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Quoting FLPandhandleJG:


Its okay.. No1 is perfect..

You must be too young to remember Cassius Clay, Bobby Charlton, Raquel Welsh, Barbie Benton...
Them, and some others, achieved Perfection in one way or another at points in their time....

just sayin'
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406. Skyepony (Mod)
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Quoting DontAnnoyMe:


Snowed hard here the other day, when it was 40F.


Yep. It happens.
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Quoting FLPandhandleJG:


They probably believe the system will probably come in sooner than they expected or depends what model they are relying on right now.. Its hard to give out a prediction in the south if u already know that u already got those cold temps already.. But if the L comes in slower and the cold catches up on time, then they will change that forecast.. JMO


Yeah, southern snow must be such a pain to forecast >.< And I can imagine the bashing a forecaster will get if they say snow in the south and no snow materializes.. So I guess it's good to be on the safe side for now, as its still 2-3 days away. Tomorrow we shall know more. :)
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting DontAnnoyMe:


Snowed hard here the other day, when it was 40F.


Nice where abouts r u ??
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Quoting pottery:

In truth, I had seen that.
But you know how the graphics sometimes dont tell the whole story.
That's Serious stuff there!


Actually, the problem was with the AP press release.

AP

Just goes to show that you can't always believe everything you see on the internet.

Except the Doc's posts, of course.
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Quoting FLPandhandleJG:


I believe it will come out near 12:30 am or close to 1am.. we will c if it stays consistent.. Hopefully a lot of us can get some dusting or some snow.. Some others could get way too much..


Yeah I hope so too, especially you guys in the panhandle that would be a real treat. In the map you posted on 373 we are barely in the C section, which shows some pretty good chances but we are supposed to be at 52 for the high that day.. A little high for a snow day. Then again, are NWS is for some reason 10 degrees warmer than the others, as evident by columbus's high being 10 degrees higher than auburn's when they are right next to each other XD
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting HurricaneSwirl:


Yeah I realize that, but the fact that TWC is predicting rain instead of snow shows what I posted, that it doesn't think it will get cold enough to snow, whether it be on the surface or not. Other sites do, but barely. I'm just hoping they are being conservative until the event gets closer.


They probably believe the system will probably come in sooner than they expected or depends what model they are relying on right now.. Its hard to give out a prediction in the south if u already know that u already got those cold temps already.. But if the L comes in slower and the cold catches up on time, then they will change that forecast.. JMO
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Quoting KoritheMan:


It doesn't necessarily have to be 32F at the surface to snow. As long as the low- to mid-level atmospheric temperatures are at or below freezing, and there is sufficient moisture from 850 mb upward, snow can fall when the temperature is above freezing.


Snowed hard here the other day, when it was 40F.
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Quoting TampaFLUSA:
Sorry, I have a hard time during yellow.


Its okay.. No1 is perfect..
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Quoting KoritheMan:


It doesn't necessarily have to be 32F at the surface to snow. As long as the low- to mid-level atmospheric temperatures are at or below freezing, and there is sufficient moisture from 850 mb upward, snow can fall when the temperature is above freezing.

Like JG said, I think it's more to do with the fact that the low appears to be weaker in the model fields at this time.


Yeah I realize that, but the fact that TWC is predicting rain instead of snow shows what I posted, that it doesn't think it will get cold enough to snow, whether it be on the surface or not. Other sites do, but barely. I'm just hoping they are being conservative until the event gets closer.
Member Since: July 7, 2008 Posts: 2 Comments: 3237
Quoting HurricaneSwirl:


Macon, GA.

I want to see the 0Z Euro as soon as possible so I can know if it follows on the "weaker" "trend" but I'm not gonna stay up for it.


I believe it will come out near 12:30 am or close to 1am.. we will c if it stays consistent.. Hopefully a lot of us can get some dusting or some snow.. Some others could get way too much..
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Quoting FLPandhandleJG:


Its the right map.. Its the yellow highlighted ones are the very artic plunge back in 1989.. Just saying!
Sorry, I have a hard time seeing yellow.
Member Since: June 21, 2007 Posts: 10 Comments: 1657
Quoting DoverWxwatchter:


For you in the deep south, where is the southern 1 inch line? It doesn't have that on the map.


I'm not really expect anything.. could get a flurry or two.. Right now, have to see if the storm does develop strong enough or not..
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Quoting HurricaneSwirl:
Aww, TWC took away my snow chances both at day and night :( The rest of the sites aren't looking so good either. Not just my city either. Weird cause according to the special advisory I'm forecast to get an inch of accumulation, but no sites even forecast the temp to get low enough to snow..


It doesn't necessarily have to be 32F at the surface to snow. As long as the low- to mid-level atmospheric temperatures are at or below freezing, and there is sufficient moisture from 850 mb upward, snow can fall when the temperature is above freezing.

Like JG said, I think it's more to do with the fact that the low appears to be weaker in the model fields at this time.
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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