It's a cold morning with temperatures in the teens in many locations. The clouds have already increased again as the next storm has sped up slightly. We could see a few snow showers reach the crest this morning and spread into the basin into the afternoon. 

More on that in a minute. Let's look at the storm totals from the last storm. We saw the steady snow slide south Tuesday morning and isolated snow showers through Tuesday afternoon. Those dropped a final 2-18 inches of snow depending on where we saw the heavier showers.

That brings the 3-day storm totals on the mountains to 3 - 6.5 feet with the big winner being Mt. Rose. Around lake level reports of 1 - 3.5 feet. The highest amounts on the West side of the lake with up to 44 inches reported at 6500' near Meyers.

The final forecast from Sunday morning was for 2.5 - 4.5 feet of snow below 7000 ft. down to lake level. Thanks to the snow levels being slightly higher than the models were suggesting we saw rain times of rain mixing in in the lowest elevations near lake level Sunday into Monday before a change to snow Monday night. That is what led to up to 1.5 feet less than the final forecast for some areas which was on the assumption of all snow down to lake level.

On the mountains, the final forecast was for 3.5 - 7 feet. We have reported storm totals of 3 - 6.5 feet. Much closer to the forecast. Some of the lesser amounts were from warmer temps and lower snow:liquid ratios, and also less total precip. The final model runs had a range of 5-8 inches of total precip along the crest, and the Snow Lab recorded 6.4 inches, with an average snow:liquid ratio of 10:1 at 6883 ft.

Here is my keep me honest forecaster report card for this storm.

An average variance outside of the forecast range of around a foot. The Snow Lab is the only location that came in right on forecast. It is also the only place being measured by an actual scientist... This one hurts. My 6-year avg. variance, since I started tracking, is 1.5 inches, so I'll need to nail the forecasts for the upcoming storms to recover from this storm.

Wednesday - Thursday Storm:

The next storm is moving in a bit faster than forecast the last few days. We are seeing snow showers already popping up on the crest NW of the lake this morning. The snow showers will increase through the day and should spill across the Tahoe Basin by Wednesday afternoon.

We are starting out cold with snow levels below 3000 ft. The atmosphere is juiced already from the last storm with humidities already at 80+% as this storm moves in. It wants to snow. Highs only in the 20s for Wednesday and Thursday for most areas.

The winds are increasing from the west-southwest with ridgetop winds to 120+ mph by Wednesday evening. That is going to affect upper mountain lift operations along with the power issues we still have from the last storm. You'll want to keep up to date directly with ski resorts on their operations, not with us. We just forecast the weather, not operations. The winds drop off through the day on Thursday.

The total precipitation amounts have trended upward on the last few model runs this morning. The high-end range along the crest is now up to 1.6 - 2.4 inches, with up to 1.7 inches on the east side of the lake. The total model average is up around 3 tenths of an inch from Tuesday and is just shy of 2 inches this morning, around 1.96". The WPC's blended model is slightly wetter than my average showing 2.25" along the crest.

This is a colder storm than the last which should keep snow levels well below lake level at their peak. Snow levels should rise to around 4000-4500 ft. by Wednesday evening as the moisture increases, and peak around 5000-5500 ft. Wednesday night, then dropping back below 5000 ft. Thursday. Snow to liquid ratios on the mountains of 12-17:1 throughout the storm for some lighter density snow on the upper mountains.

We could see 1-4 inches on the mountains and a dusting up to a couple of inches at lake level through Wednesday afternoon. Then the heaviest snow moves in Wednesday evening into early Thursday morning with 9-20 inches possible on the mountains and 6-12 inches at lake level. Then snow showers Thursday could drop a final 1-4 inches before ending by Thursday evening. Here is the final forecast for this storm.

We will tally up the totals again Friday morning. Hoping to get a better report card. I get flashbacks of being grounded when I bring home bad grades...

The Weekend:

High pressure builds in over CA for the weekend.

We should see sunny skies and slightly warmer high temperatures Friday into Saturday with highs into the 30s. Sunday should be dry but with increasing winds and maybe increasing clouds as the next storm approaches. Ridgetop winds could be gusting from the southwest up to 80+ mph and could affect some upper mountain lift operations.

A deep trough dig down along the West Coast by Monday through next week.

Storms will spin up on the trough and some will tap into deeper Pacific moisture and push into CA. The first storm is forecast to be off the coast by Monday and tapping into some subtropical moisture. Some forecast models are showing the precipitation falling over northern CA by Monday, but struggle with how far east it pushes towards teh Tahoe Basin.

We will have to watch this closely for Monday. There is better agreement we see the rain and snow push into the Sierra by Tuesday, and into next Wednesday.

We could see another AR (atmospheric river) event but not forecast to be as strong as the one we just had.

The latest model runs are also a little colder and trying to keep snow levels near lake level again. I'm not going to get your hopes up this time. We will need to update the details on timing, precip amounts, snowfall potential, and snow levels as we get closer. 

There is decent model agreement that there may not be much of a break between that storm and another storm moving in by Christmas Eve into Christmas Day.

If you have travel plans through the Sierra you will definitely want to stay tuned to the forecasts. I also write a specific travel forecast after I post this forecast each day, the I-80 CA Daily Snow. Here is a look at the OpenSnow graph for the GEFS model showing the trend for increased precipitation totals through the 25th.

The European and GFS forecast models both show up to 9+ inches of total precipitation through Christmas Day. Below is the Euro ensemble mean model showing up to 7+ inches. We'll have to keep an eye on snow levels for the lower elevations with each storm, but the mountains could continue to pick up feet of snow.

Fantasy Range:

The long-range models continue to show the mean trough position over the West through the end of December.

That should keep temperatures on the colder side and keep the storm door open. The long-range models continue to show storms moving into CA through the last week of December. If the forecasts continue this trend we could see quite a bit of snow this month. 

The December average for total snowfall at the Central Sierra Snow Lab near Donner Summit is 67 inches. We have already surpassed that. So the rest of the month is bonus snow. The record is 179" in 1970. Here is a look at the 50-year graph.

I love numbers and stats, especially when they are snowfall numbers that we are tallying. Let's hope this great start continues into the season as the ski resorts get open and start to expand terrain.

Stay tuned...BA

PS – We are going to make some significant changes to OpenSnow through the second half of December. If you’re an All-Access subscriber (thank you!), you’ll see no changes. If you are not an All-Access subscriber, here is an FAQ with more details about the upcoming changes, and we hope that eventually, we’ll earn your support.

Fresh Tracks! Season 2, Episode 6:

On this week's episode of The Flakes, BA, Mike, & Evan discuss: Snow Level Forecasting, Atmospheric River Events, 5 Day Snowfall Reports for Each Ski State, 5 Day Snowfall Forecast for Each Ski State, The Long Range Forecast Discussion, Where you should go skiing tomorrow, & The Changes Coming to OpenSnow and Why. Give it a listen!

(Sorry about the little bit of distortion this week when I got loud, I'm a loud Italian, I'll fix that for next week)