Sorry for the late post but I was trying to scrape together the snowfall reports from the storm which were slow to come in. What a storm! We set some records and started off the snowfall season with a big start.

Storm Totals:

The final model runs we looked at ahead of the storm on Satuday morning had a range of 6.5-8.2 inches of total precipitation along the crest, with an average of around 7.5 inches. We joked about the GFS model being out of its mind a few days earlier showing over 10 inches of liquid. Well...we saw up to 12+ inches of total precip on the crest and up to 10+ inches to the east side of the lake.

We saw some 24-hr precip records set, like the 10.4 inches in Blue Canyon. We also set some October records like the 16" of total precipitation recorded at the Central Sierra Snow Lab which beats out October of 2016 by 0.33 inches.

For elevations above 9500' that saw all snow the totals were likely impressive, but no one is up there to measure it and the SNOTEL sensors are not very accurate for snowfall, especially with 140+ mph winds. We have a snowfall estimate map on our Maps page that looks at radar trends and sensors. That shows up to 60+ inches of snow near the Mt. Rose wilderness area, which seems reasonable with 10+ inches of total precip on the Mt. Rose SNOTEL.

Down below 9000' where we do have people measuring the snow we saw mostly rain through Sunday evening. Then snow levels dropped later in the evening and overnight. With the heavy precipitation continuing the snow started piling up very fast, up to 3"+ per hour. As an example, Sugar was bare at the base through 10 PM and snow started to stick by 11 PM. By 7 a.m. they had 2 feet of snow on the ground at the base in just 8 hours.

If you want to check the SNOTEL sensors yourself, this is a good link.

Interactive Map (usda.gov)

At lake level, we saw rain turn to snow after midnight with heavy wet snow through Monday morning. I received a lot of pictures and reports from readers, which is VERY helpful with getting an idea of what happened with a storm. The best place to post them is in the comments below, tweet them to @TahoeWeather, or tag @TahoeWeather on your Instagram stories. Reader reports of 6-16 inches around the lake for this storm.

The Snow Lab recorded 33" of snow at 6883' near Donner Summit. That brings the October total to 48", just 1.9" shy of the record from 2004!

The ski resorts that were measuring reporting, 6 of them around the Tahoe Basin, reported 30-42 inches on the upper mountain after a change to snow Sunday night. 1-2+ feet for the base elevations. Farther south the snow levels took longer to fall but still a respectable 22-36" for Dodge Ridge and Mammoth.

As you can we are now close to 500% of average snowfall for the date. What a storm! One that we will remember for years to come. I guess the GFS model was not out of its mind last week, it pretty much nailed the forecast when it showed up to 12 inches on the crest last Wednesday...

Even though half of the mountains aren't reporting yet, I did dust off the Keep Me Honest Report Card. The final forecast goes out Before a storm arrives and the report card comes out After the storm ends. In this case 3 Days later...

The snow levels fell faster than expected Sunday night. That caused most of the errors in my forecast with this storm. The 4-inch average variance was under forecasting the snowfall amounts Saturday morning.

I have always scored myself to continue fine-tuning my forecasting methods each season. It also helps with the conspiracy theories that we always over forecast storms on purpose. All of my forecasts and report cards are posted on this page back several years, and I'm always happy to share the Before and After, forecasts vs actual snowfall, for any storm from my records.

What's Next?:

We have gusty winds and clouds Tuesday with highs only in the 30s. Most of the showers look to stay to our north through the evening, except maybe up along the crest. Snow levels rise up to around 11,000 ft. by Tuesday evening.

Then high pressure builds in through Friday with warming temperatures and lighter winds. We should see mostly sunny skies Thu-Fri with highs into the 50s at lake level and 40s for the upper mountains.

By Friday night into Saturday, the ridge shifts east, and a weak system may move through to our north.

Some of the model runs suggest we could see a few showers far enough south to brush the Tahoe region, but the snow levels look to be above 10,000 ft. So just rain showers if they make it this far south. Here is a look the WPC blended model for total precipitation through Saturday.

Sunday into next week another weak ridge is forecast to build over the West. 

But it could be a dirty ridge as a system tries to move into CA Monday night into Tuesday. The GFS model has it falling apart, but the European model shows it holding together enough for light precipitation. Snow levels would likely still be high if we see any precip.

If the GFS model is right we will likely stay dry through next Thursday. Highs likely in the 50s most days at lake level and 40s for the upper mountains.

Fantasy Range:

The long-range models are shifting slightly starting around the 5th. The latest model runs suggest we could see a large trough in the northeast Pacific that could push into the West Coast between the 5th-7th.

That could open the door to wetter systems. The long-range ensemble mean model runs show increased precipitation days 10-14.

We'll see... But that looks to be the next chance of any meaningful rain or snow right now... 

We were planning to do a season forecast post but the storm happened and delayed that. I'll have that out in the next few days. Also, a lot of people are asking about snowy Octobers and how they correlate to the rest of the season. Looking at the last 6 with 20+" in October, there's no correlation to the rest of the season with well above and below-average seasons, and some in the middle.

A lot more goes into what could happen the rest of the season. We'll dabble in that while we wait for storms to return.

Stay tuned...BA