Milder and more average weather for this time of year has moved back in to the start the week. Highs at lake level are back into the 40's, and 30's on the upper mountains. The next storm moves in Thursday with high winds on the mountains and then a cold front pushing through by Thursday evening. That will bring moderate snowfall Thursday evening through Thursday night. We could see several inches of snow on the mountains with a few down to lake level.
We clear out going into the weekend with seasonal temps, and then a weak system may push light snow in later Sunday into next Monday. After that the forecast models are split on whether we go into a dry pattern for a week, or so some more weak to moderate systems push in.
I hope you all had a good, safe, and warm Thanksgiving holiday. It was definitely a cold stretch of weather and only yesterday did the temperatures finally get near freezing and the plows were able to get some of the snow off the roads around town. With the flow off the Pacific to start this week the temperatures will be much closer to normal for this time of year so we will see the roads clear and snow start to melt at lake level.
A weak system is moving into the West Coast today and falling apart as it encounters the ridge over the West. It is pushing in a bit more precip than was thought a couple of days ago. That could mean that if you are up on the mountains skiing today you could see some snow flurries or a brief snow shower. For the rest of the area some clouds will be moving through today.
A stronger trough will push towards the West Coast on Thursday. As mentioned in the last post the flow will be Southerly and the winds should pick up and gust pretty good on the mountains Thursday. The Southerly flow ahead of the cold front should keep the snow limited to the crest during the day. The GFS has slowed the timing of the cold front pushing through until the evening while the European model is faster. Expecting the precip to finally push into the basin with the front by Thursday evening with moderate snowfall that tapers off by Friday morning.
Snow levels will start just above lake level Thursday, but will quickly crash below lake level with the front and heaviest precip pushing in. The GFS has been wetter on the last few runs, but Euro is still showing the same amounts the last 2 days. The GFS is showing about a half inch more in total liquid than the European forecast model.
The Canadian model is showing a weaker system as it encounters the ridge over the West and bumped a bit further North with the ridge building off the coast. It has very light amounts reaching the Sierra.
Because of the discrepancy I can't go with the GFS and call for 12-18 inches of snow on the mountains. For now I'll stick with the forecast I've had posted the last 2 days which is middle of the road in line with the Euro. The only difference you will see on the forecast on the individual resort pages is that I pushed some of the snowfall accumulations into Thursday night. Forecast is still for a few inches possible at lake level, 3-6 inches on the mountains on the East side of the lake, 6-9 on the West side, with maybe up to a foot on the highest peaks West of the basin along the crest.
High pressure builds in behind the storm going into the weekend with seasonal and dry conditions. A weak system that looked like it would stay to the North later Sunday into next Monday is trending a bit further South on the models this morning. We will watch the trend on that but at most it may bring a light amount of precip in.
Next week a stronger ridge of high pressure looks like it will build off the CA coast. That may keep the storm track to the North next week. The European model is still trying to push in a trough next Thursday, but the majority of the model runs and ensembles show a stronger ridge keeping us dry.
Going beyond 10 days into the unreliable range of the models we start to see a split on whether the ridge stays or retrogrades away from the coast. Even some of the ensemble runs that retrograde the ridge don't bring in a strong trough, just chances for more weak-moderate systems returning by the end of next week. Some runs however like the GFS and Canadian ensemble control runs show a strong trough moving into the West Coast.
So the long-range of the models continue to be all over the place as they struggle to pick up on the changing pattern as we go into Winter. I think the active weather will continue but I am not seeing a big storm yet and we need to start getting some bigger storms instead of these small storms we have been getting in November.
November was a cold month and we saw a cold storm each week. The big news of the month was the cold that brought snow to lake level, keeping the snow that did fall on the mountains from melting, and allowing record amounts of snow making. The other side to that is that for overall precip it was a dry month and we didn't see any big storms. Reno is the exception with the inside sliders bringing above average snowfall. Officially from the snow label I'm expecting that we saw only around 60% of average snowfall for Tahoe. The snowpack measured on Wednesday after the storm showed the Northern Sierra at only 47% of average, and Central Sierra at 70% of average.
For precip we are only running at 54% of average now for the water year. We are actually running behind the last 2 years.
Here is what that looks like on a map
The central and Southern Sierra to our South and Nevada to our East are above average so far for the water year since October 1st, but Northern CA is way behind. I'm watching the media hype all the snow from El Nino and I'm sitting here watching us get further behind and having some catching up to do once or if we see the El Nino conditions bring a change to the pattern with above average precip starting in January...
Like I said I'm not seeing anything significant on the horizon the first 2 weeks of December. Here is a look at the latest CFS total precip forecast for December. This would bring about average precip for December for Northern CA, so we would head into January still behind. We are still expecting the heaviest precip caused by the El Nino pattern to start in Janaury through March.
I was reading the updated Winter forecast from accuweather.com this weekend. They are still showing a forecast for above average snowfall, but have bumped the precip amounts up for the Pacific NW. We discussed that trend on the climate models in our last El Nino discussion. Central CA does look like it could see the highest amounts of precip based on the latest climate model trends. That is a change from earlier in the Fall and from average El Ninos that see the heaviest precip in Southern CA. So we do have a chance for a comeback as we go into the heart of Winter...
The Opensnow updated Winter forecast for snowfall by mountain will be out on the 10th.
One interesting thing that accuweather noted in the risk section of the forecast...
The European model over the past few runs has been drier than most models for California. Could the unusually warm water west of California actually lead to higher upper-level heights and deflection of heavier precipitation events in central and Southern California? This could mean heavier precipitation farther up the coast. January is the critical month and the biggest difference between the European and other models. Other models like the NMME, IMME and CFS are wetter
This is something I've talked about several times through El Nino and Winter forecast discussions. My thoughts were that the high pressure may be a bit further North suppressing an undercutting jet further South into Southern CA. That is something that weatherbell has mentioned in their Winter forecast as well. This comment by accuweather would keep the ridge further South off of CA like the pattern we see next week with storms further North. That may still keep heavy precip in Northern CA during the Winter. Neither scenario is still most likely and we get a wet CA as a whole like the majority of climate models show. It is just interesting that it is being mentioned by several forecasting sites as a possibility that we don't see the typical El Nino pattern this season with all the warm water in the Eastern Pacific.
It would be more comforting though if we could get at least one big storm in December to get us going instead of these small storms.