Ramblings:

I am posting late today.  The day got away from me with a zillion things since early this morning.  But I figured it would work out because I will be on the road early tomorrow morning and now able to update again until this same time tomorrow.

We as forecasters look at dozens and dozens of model runs throughout everyday to watch the trends and get an idea of what is going to happen, especially us snow forecasters trying to do pinpoint accuracy on snowfall amounts.  When you get a busy day that keeps you away from that you fall way behind and spend hours catching up like I have been doing this afternoon.

I am trying to get a handle on the storm this weekend, and the long-range.  Some of you are running the free GFS model which is showing insane amounts of snowfall over the next 2 weeks, so we will look at that as well.

I'm not hearing much buzz around town about the storm for this weekend.  I think because of the forecast for shadowing which is the crest blocking most of the precip from reaching the Tahoe Basin.  But a lot of ski resorts are located West of the lake near or on the West side of the Sierra Crest, and this storm could bring decent amounts of snowfall to that area.

The Weekend Storm:

We have a strong and slow moving storm approaching for the weekend.  It will push a stream of moisture in CA on Saturday.  The flow will be Southerly which doesn't help with pushing the precip East over the mountains and into the basin.  That is why the forecast has been meager for the basin this weekend.

The winds will start to pick up Friday and then will be gusting pretty strong over the weekend near hurricane force up on the mountains with gusts over 70mph.  Which is normal for a storm this strong.

Looking at the trend on the forecast models today the GFS and Canadian models have been showing more of a push of the precip over the crest Saturday into Sunday.  I'm not sure I believe it yet and you would want to see the winds more SW.  The precip can eventually push through as the trough pushes inland Sunday night, but the models have been showing this storm splitting apart before then.  The European and NAM forecast models still show a good deal of shadowing until Sunday night.

Here is a look at the GFS and Canadian model runs from today that show more precip making it into the basin through Saturday through Sunday night.

We are not allowed to redistribute the Euro.  You can see up to an inch of liquid reaching the East side of the lake and up to 2 inches West of the lake near the crest.  We already knew we could see some decent snow on the crest but we will have to watch to see if there is more of a push of precip further East and snow for all the mountains.

Snowfall:

The snow levels fall to around 7000 feet or just above by Saturday evening, and they look to stay there until the trough pushes in Sunday night, but by then the the storm is winding down.  So not expecting any snow below 7000 feet until maybe a little Sunday night.

Here is the updated snowfall forecast by morning.  

People always ask how this relates to their mountain.  These forecast graphs are mean to be a summary of all the work I put into hand keying the daily and nightly snowfall amounts for the next 10 days for each ski resort.  You can find your ski resort page which has the 5 and 10 day snowfall forecast.

Looking at the ensemble members of the models you can see the average snowfall forecast for Donner Summit at 7000 feet is around 17 inches this weekend.  They don't include the drier European model which is dragging my forecast down to about 12 inches for the same location.

The ski resort pages show the snowfall forecast for the upper mountain.  So 10-15 inches above 7000 feet that is possible this weekend is not bad in my opinion, just surprised not many people are talking about it only 2 days out.  Hopefully tomorrow evening we have better agreement with the European model and a better idea of the amount of precip that will push into the Tahoe Basin over the weekend.

Early Next Week:

We should have a break Monday and Tuesday before a cold but weak system pushes through Wednesday.  This storm has trended snowier on the latest GFS run with several inches for the mountains, but the European model did the opposite and now splits apart the storm with no snow.  So the model madness continues and we will continue to try and make sense of it.  Hopefully the GFS is right and some more fresh snow before the holiday, but it is the busiest travel day of the year so not good for travel in the mountains.

There are a couple ski resorts trying to open for tomorrow and many more trying to open over the next week.  With the fickle weather lately I'd rather announce openings the day they are for sure.

Here is a look at the pattern on Thanksgiving as forecast by the GFS ensemble mean model.

You can see the cold trough in place over the West Coast with a reinforcing trough headed down from the Gulf of Alaska.  That is in place by next Friday into the weekend of the 26th.

Real Snow Week 2?

This is now the beginning of the week 2 period I have been hyping somewhat because I like where the pattern is heading, but I haven't talked about snowfall potential.  I like that strengthening ridge near the Hudson Bay and North of Hawaii.  This starts to setup a pattern for cold strong storms for Tahoe.

It is still more than a week away and I don't talk about specific storm until they are in the 7 day window, and snowfall amounts until the 5 day window.  Beyond a week we usually just talk about patterns.  

The forecast models are showing a stronger storm for the day after Thanksgiving and with more lined up going into that weekend.  The way the pattern is showing on the ensembles of the GFS, Canadian, and European models I would believe it, but of course the forecast has to hold.

The forecast has been fairly consistent over the last week or two for the end of the month and we have talked about it in almost every post.  Here is a look at the pattern by December 3 on the GFS ensemble mean, which could be the pattern coming to full fruition.

To me this makes sense looking at the forecast for the AO (arctic oscillation) going negative.  

In that pattern the circulation around the North Pole relaxes and the cold air pushes South.  Usually you will see blocking highs setup in the Northern latitudes, and the jet stream suppress underneath.  That is what the ensemble runs are showing with the cold over the U.S. and storms moving West to East from coast to coast.  That would be a completely opposite pattern to what we have seen the first half of November, and would start to pile up snow on the starving mountains from coast to coast.

Now in these blocking patterns it can setup that the trough locks in over the East or the West and it's not coast to coast.  I fear that it locks into the East weeks 3 & 4.  But if we can get this to setup right weeks 1 & 2 it could give us a big boost and something to start with.  

Premonishment/Disclaimer:

Some of you run the free GFS model and someone posted the total precip for the next 2 weeks in the comments of the last post.  I don't like to post precip or snowfall amounts more than 5 days out too often because storm specifics beyond a week change.  But I have been emailing sneak peaks to some of my friends in the ski industry.

The European weeklies a week ago were showing lots of snow the end of the month into December, and for the past week the GFS has been showing the same.  I am going to break my rule just this once and throw you a bone.  I know this is dangerous because we have weak hearts after the 2011-2015 seasons, which is why I am careful not to get everyone's hopes up if I can help it.  

Here is the 10 day total precip forecast on the latest GFS run.  15 inches of liquid on the West slope, half that on the crest and way less across the basin, but still wet.

Here is the snowfall forecast for the same period.  A lot of this is from the weekend after Thanksgiving.

Here is the 16 day total snowfall forecast.  

112 inches in Truckee?  That seems a little overdone...  Like I said, don't look at the specifics.  Just take away that there is a chance that a good pattern for cold storms could setup for week 2.  Let's just keep praying and tracking and hope we continue to trend that direction.

If you are an all access member and you take a look at the 10 day forecast on a ski resort page you will see the snowfall forecast spike days 8-10.  Days 1-7 are running off a model average, but 8-10 just off the GFS.

Stay tuned...BA

P.S.  See what happens when I don't write for 36 hours, my mind explodes on the page...

Don't forget that we are now forecasting for the Mammoth area.  So be sure to start checking out Howard's discussion on that page as well! https://opensnow.com/dailysnow/mammoth