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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It is incredibly difficult to find complete hurricane tracking maps for basins -- wu's atlantic one is the only one that I found that was satisfactory for any of the six basins.
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538. xcool
good nigth all
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537. xcool
traumaboyy hey
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Well as the models attend to be weak for now.. Get a better idea if this going to be something or just an average storm system.. but for now, Im going to try to sleep.. Everyone have a goodnight..
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Quoting DoverWxwatchter:
I don't remember a storm in Cali before the superstorm.

The 1993 setup was different, a very strong short wave came in from Mexico across the Gulf, another wave dropped down from the north and phased with it as it entered the southeast, and a third wave phased and kept it intensifying up the mid-Atlantic.

Looking back at LAX the week before the 1993 superstorm, there was some light rain but no storm.


Okay.. thx for the info.. maybe i picked the wrong year.. lol
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Does anyone know if there was a comparison that this current storm that hit Cali that set some records now did some similar stuff back in '93?? Some reason I think has some similarity but not saying it will happen.. Just to keep in mind..
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Quoting xcool:
brb


What up Bro!!
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Quoting DoverWxwatchter:


I suspect the downslope winds off the southern Appalachians will dry out a lot of that precipitation over north Florida, GA and SC.


We will c.. that one was just a median tho.. some more models should be coming soon.. Im seein if Euro stays consistent or not..
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Quoting JFLORIDA:
if anything, the sun contributed very slight overall cooling in the past 25 years.


which did not happen.





Is it going to be argued now a combination of unknown and mysterious cycles will certainly save us?


Since we're talking sun, what about this study?

http://www.nasa.gov/topics/solarsystem/features/solarcycle-sorce.html

Just a sample:

"...As recently as the 1970s, scientists assumed that the sun's irradiance was unchanging; the amount of energy it expels was even called the "solar constant." However, instruments similar to the Total Solar Irradiance Monitor (TIM) and the Solar Irradiance Monitor (SIM) have made clear that the sun's output actually fluctuates in sync with changes in the sun's magnetic field.

Indeed, TIM and its predecessor instruments, whose records of irradiance began in 1978, show that the sun's output varies by about 0.1 percent as the sun cycles through periods of high and low electromagnetic activity every eleven years or so. In practice, this cycling means the sun's brightness, as measured by TIM, goes up a bit when large numbers of sunspots and accompanying bright spots called faculae are present on the sun, yet goes down slightly when sunspots and faculae are sparse, like they have been in the last few years as the sun has gone through an unusually quiet period.

However, there is a critical difference between the SIM and TIM, explains Jerry Harder, the lead SIM instrument scientist and a researcher at the Laboratory for Atmospheric and Space Physics (LASP) at the University of Colorado in Boulder. While the TIM lumps all wavelengths -- including infrared, visible, and ultraviolet light -- into one overall measurement, the SIM isolates and monitors specific portions of the spectrum.

Notably, this makes SIM the first space-based instrument capable of continuously monitoring the visible and near-infrared portion, parts of the spectrum that are particularly important for the climate. SIM also offers the most comprehensive view of the individual components that make up the sun's total solar irradiance to date.

Some of the variations that SIM has measured in the last few years do not mesh with what most scientists expected. Climatologists have generally thought that the various part of the spectrum would vary in lockstep with changes in total solar irradiance.

However, SIM suggests that ultraviolet irradiance fell far more than expected between 2004 and 2007 -- by ten times as much as the total irradiance did -- while irradiance in certain visible and infrared wavelengths surprisingly increased, even as solar activity wound down overall.

The steep decrease in the ultraviolet, coupled with the increase in the visible and infrared, does even out to about the same total irradiance change as measured by the TIM during that period, according to the SIM measurements.

The stratosphere absorbs most of the shorter wavelengths of ultraviolet light, but some of the longest ultraviolet rays (UV-A), as well as much of the visible and infrared portions of the spectrum, directly heat Earth's lower atmosphere and can have a significant impact on the climate..."

In short, old instruments weren't able to separate the light spectrum, newer ones can.

They're seeing variations in the UV that weren't seen or measured before.

So there may very well may be some "unknown and mysterious cycles" that we're just beginning to see.
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Euro is starting and CMC is i think or almost done with the runs..
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515. xcool
brb
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514. xcool


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Quoting xcool:


quite interesting .window shear map...


Yea i would say..
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511. xcool
yay im here
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510. xcool


quite interesting .window shear map...
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Quoting xcool:
cmc hmmm


Sup Scott.. U made it.. ;)
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508. xcool
cmc hmmm
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Quoting caneswatch:
Central South Carolina on Sunday:

A chance of snow. Partly sunny, with a high near 41. Chance of precipitation is 30%.

From NWS Columbia, SC

So far, so good. Looks like it'll be staying that way.


Yea thats being safe for now.. Everyday can change if there is potential storm.. Just saying! But right now models arent agreeing at the moment.. Just a safe forecast..
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506. Inyo
Quoting JFLORIDA:

I think no matter what come jan 1st something notable will also occur.


Well, the latest run wasn't a rainy wash-out in Vermont but would probably have freezing rain and a wintry mix mess.
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GEM Model
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wow.. that would be crazy..
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Central South Carolina on Sunday:

A chance of snow. Partly sunny, with a high near 41. Chance of precipitation is 30%.

From NWS Columbia, SC

So far, so good. Looks like it'll be staying that way.
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Quoting melwerle:
sending it your way...hope you get something but you don't want what we had. Light, lovely, easing of the drought conditions rain. Good luck to you.

Taking my soggy butt to bed.



Yea i def dont want all that rain at once.. But hope it clears up soon in time for christmas.. Goodnight and gotcha y'all in my prayers.. Be safe and Happy Holidays!
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sending it your way...hope you get something but you don't want what we had. Light, lovely, easing of the drought conditions rain. Good luck to you.

Taking my soggy butt to bed.

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Quoting melwerle:
Fl...no more rain, no more rain, no more rain. Let's do the chant together.. :)

I think really NRA got more than we did - she must be busting out a rescue boat.


I was talking about for the south and the southeast would take that rain from ya..
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Quoting caneswatch:


The entire east coast, or from where to where?


Sry I meant from atlanta up to the carolinas, possibly tennessee, up to virginia and up to the northeast.. Central and south fla probably get t'storms and rain.. Sry I didnt explain myself again.. I attend to do that sometimes.. what happens when ur tired and can't sleep..
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Fl...no more rain, no more rain, no more rain. Let's do the chant together.. :)

I think really NRA got more than we did - she must be busting out a rescue boat.
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Quoting FLPandhandleJG:


i was saying the potential system we may have this weekend could stop a lot of traveling plans this weekend into monday and possibly tuesday.. Sry that i didnt explain myself well..


The entire east coast, or from where to where?
Member Since: October 8, 2008 Posts: 14 Comments: 4553
Crazy stuff here yes, but that didn't stop me from driving 25 miles to get a cheesesteak b/c I needed comfort food. :) Families during the holidays can do that to you!! I would have driven in a tornado warning when I was back south to get one today. Christmas crazies!!!
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Quoting melwerle:
Please hush!!! John Coleman has been on vacation lately and he's hte only one we listen to with regards to weather. No more rain.


Sry but i just saying.. Wish y'all dont get anymore we sure need over in the south and the southeast.. But im praying that y'all dont get anymore and get a break.. Its just sad to c.. Thats your opinion and I am fine with it..
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Crazy stuff, in Cali. Wow.
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Yep and according to the local news here, they are still having the Poinsettia bowl here. The only real problem I see if that traffic is going to be a serious issue with most of the roadways closed off due to flooding. It's really ridiculous - two of the major upscale malls are right there, it's Christmas and traffic around here at this time is already screwed. Now it is doubley screwed. Today when we were trying to get to the mall, i sat in traffic for 45 minutes before i finally bailed and got on the freeway and drove 40 minutes east to another mall. There were rescue crews trying to get through and they couldn't. It's ridiculous.
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Quoting FLPandhandleJG:


i was saying the potential system we may have this weekend could stop a lot of traveling plans this weekend into monday and possibly tuesday.. Sry that i didnt explain myself well..




Ah, I hear ya. Thanks.

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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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