Multiple atmospheric river events for CA in the next 2 weeks- major flooding and massive snows very possible.

[Cheeznado]

Extremely good model agreement on an epic pattern for the West Coast, especially California. Yes, the attached is a very likely overdone GFS snow total map for the next 15 days but 360" of snow?????? The ensemble mean is much less, but much less in this case is still AOA 150"" 

[CheeselandSkies]

CA desperately needs precip, so of course it will come all at once. Thanks, atmosphere!

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[Cheeznado]

San Francisco just set its all-time 24 hour rain record. Moderate to major flooding ongoing in several locations. Up to 10" of rain in some higher spots. And this is just from the first system!

[Ed, snow and hurricane fan]

Atmospheric river model site from UC San Diego.  https://cw3e.ucsd.edu/iwv-and-ivt-forecasts/#IWV

[CryHavoc]

We just experienced roughly 85 hours of nearly non-stop rain in the North Bay Area.  Ground is completely saturated and localized flooding has been relatively intense.  The volume of water here is absolutely impressive.  A small stream in my yard that is dry most of the year is loud enough to hear from 100+ feet away.

Have measured 7.84" of rain in the last 3 days.  Today is supposed to be a respite, but the next 6 days are all projected to have rain with some periods being very heavy.

Definitely concerned about mudslides here as well as generalized flooding.

Yesterday 4 different roads in the Tahoe area was shut down, and driving anywhere was a nightmare.

Will report back as the rains resume tomorrow.

[Cheeznado]

On 12/31/2022 at 8:52 PM, Cheeznado said:

San Francisco just set its all-time 24 hour rain record. Moderate to major flooding ongoing in several locations. Up to 10" of rain in some higher spots. And this is just from the first system!

Actually this came in in second place, still impressive.

[etudiant]

California has a record of really impressive rain events, presumably driven by atmospheric rivers.

Case in point is the 1862 experience, which left the Central Valley flooded over 300 miles long, 20 miles wide and 30 feet deep for half a year.

The event was carefully documented by William H Brewer, hired by the Legislature to perform the first botanical survey of the region. 

https://placesjournal.org/workshop-article/learning-from-1862-drought-and-deluge-in-californias-central-valley/?cn-reloaded=1

More recent studies suggest similar events would be capable of causing damage in the $1 trillion class.

https://www.wunderground.com/blog/weatherhistorian/californias-superstorm-the-usgs-arkstorm-report-and-the-great-flood-.html

The ray of light is that there has not been the kind of really extended drought that seems to prefigure the extreme rainfalls.

 

 

[CryHavoc]

 

The national weather service for the bay area just released the most recent disco, and they're using some... Concerning language.

>To put it simply, this will likely be one of the most impactful systems on a widespread scale that this meteorologist has seen in a long while. The impacts will include widespread flooding, roads washing out, hillside collapsing, trees down (potentially full groves), widespread power outages, immediate disruption to commerce, and the worst of all, likely loss of human life. This is truly a brutal system that we are looking at and needs to be taken seriously.

[SolidIcewx]

It’s nice to see rain for the west but this is too much of a good thing

[CryHavoc]

Latest forecast disco is out:

Next message to convey is resiliency as this will not be a "one and done" storm. Details are still hard to pinpoint but resounding message is several more storms look to be lined up for this weekend, into next week and towards MLK weekend. The cumulative effect of these storms could be quite debilitating.

At this time we expect Friday to be a relative break in the storms day. (i.e. dry).

Next storm looks to arrive Saturday into Sunday and it does look to have AR characteristics with high moisture plume.

Current timing would bring a break later Sunday into early Monday with yet another moderate to strong AR possible later Monday into Tuesday of next week followed by a brief break and another system towards the end of next week. Of course timing and details will change but the theme remains the same. A storm train of systems looks to march across the Pacific and impact much of NorCal through at least next week and possibly through MLK weekend. It's noted that the operational gfs runs out through Jan 19th show precip chances.

___

All bay area residents are being advised to prep for evacuation, even for areas that are not flood/ff prone.

It's hard not to be worried given the strength of these systems. Give me comparatively tiny tornadoes any day to these behemoth systems that just dump inordinate amounts of water everywhere for days and days at a time.

[Terrier]

Almost looks like an eye forming on the GOES west imagery

[Bostonseminole]

Gonna get it good here on the central coast!


.

[Jebman]

On 12/28/2022 at 12:17 PM, Cheeznado said:

Extremely good model agreement on an epic pattern for the West Coast, especially California. Yes, the attached is a very likely overdone GFS snow total map for the next 15 days but 360" of snow?????? The ensemble mean is much less, but much less in this case is still AOA 150"" 

Ski resorts will be jumping for joy!!!!!!!!!!!!

[Chinook]

I have heard reports of rivers flooding massively in California in these past days, in response to 5-15" of precipitation in northern California.

 

 

 

 

[Jebman]

Just absolutely massive amounts of wind-driven snow are piling up on those mountains! Ski resorts are doing beyond fantastic!!!!!

 

[olafminesaw]

10 hours ago, Jebman said:

Just absolutely massive amounts of wind-driven snow are piling up on those mountains! Ski resorts are doing beyond fantastic!!!!!

 

Looks like some areas may receive 80-100" of snow in a 24 hr period. The change in weather conditions in a straight line from the coast, to Nevada across the state is insane. 

[etudiant]

California gets massive rains from atmospheric rivers periodically.

When Leland Stamford was sworn in as Governor in 1862, Sacramento was so flooded he had to take a boat to his inaugural.

William Brewer, hired by the State to survey the area, reported extensively on the event, which left the Central Valley under 30 feet of water. See his notes in 'Up and down California'.

Imho, the interesting element is his offhand  comment that the native Indians had all moved to higher ground before the event, so they knew what was coming, unlike the incoming settlers.

[CryHavoc]

Checking in. Over 14 inches of rain have fallen here in the past week.

We had some thunder, lightning, and even some mesos forming over the bay area today. Had two rounds of pea sized hail here.

Flooding is a major concern in many areas, thankfully my locality is in good shape.

[donsutherland1]

California's annual rainfall has grown more variable in recent decades.

[Chinook]

Measured precipitation for past 3 weeks. San Francisco, Sacramento, Reno, Bishop CA, Elko NV, and Ogden UT had the #1 highest precipitation compared to the historical record (considering the same calendar days)

 

[Ed, snow and hurricane fan]

Another one today.  78 mph gust at SFO and numerous power outages in Alameda (Oakland and the former NAS Alameda, where I had the bad luck to live at off and on for two years.

[Chinook]

California has gone from flood to drought to flood. Sacramento had apparently 5.12" of precipitation in January. (I added this. The NOWDATA info said the data was missing) and already 2.98" between March 1 and March 15, making for 19.46" of precipitation since November 1st. That's almost 3x higher than the 2020 calendar year.

[Ed, snow and hurricane fan]

Didn't expect this.