Tahoe Daily Snow
By Bryan Allegretto, Forecaster Posted 4 years ago November 11, 2019
Stuck in the Gate...
Summary
- Sunny weather expected through the week. High temperatures in the 60s at lake level and 50s on the mountains. Overnight lows in the 30s. - Later in the week into the weekend, we may cool a few degrees with highs in the 50s and overnight lows into the 20s in the valleys. - The dry weather may continue into next week. - We may start to see a change in the weather patter later in the month.
Short Term Forecast
We are still stuck in the gate waiting for the first significant snowfall of the season. Right now we will settle for at least some cooler air as warmer temperatures and overnight inversions are keeping the ski resorts from getting good snowmaking conditions.
High pressure is anchored off the West Coast keeping us in a mild and tranquil weather pattern.
The forecast models were hinting at the ridge weakening around mid-month. That is still forecast for later this week...
But now that we are only 5 days away it looks like all that will do is to allow a few storms to push into the Pacific Northwest later this week into the weekend. We should stay dry in Northern California. What may be slightly better news is that overnight lows may drop into the 20s in the valleys and up into the higher elevations making for some better snowmaking conditions.
Mt. Rose has been operating weekends and Boreal had a hike up park this past weekend. More ski resorts wanted to try and open next weekend, but I'm not sure if they will be able to make enough snow or not by then.
Early next week the forecast models have the ridge rebuilding off the West Coast again. That should continue our dry weather and may warm temperatures back up a few degrees as well.
The 7-day precipitation forecast continues the rain shield over CA...
A lot of locals I've been talking to aren't that concerned right now as it is only early November and most ski resorts usually don't open for a couple more weeks. Most seasons it is on man-made snow. I think after last February and the previous March we know the beating winter can bring in one month and sometimes not until late in the season. Some people may still be recovering their arms from last February's 300 inches.
Below is the November snowfall graph from the Central Sierra Snow Lab near Donner Summit. You can see that only around 1/3 of November's even hit the average snowfall for the month. That average is only from a few big Novembers boosting the average. So November tends to be a boom or bust month but leans heavily towards bust historically.
We could easily pick up the average snowfall with a few storms the last week of the month...
Extended Forecast
The big question is, will that happen later this month? In the last post on Thursday I went through how some changes were showing up in the GFS models and a little in the Canadian models as well, but not the European. There really isn't much change to that in the long-range yet.
I am looking at the model runs full-time and reading as many discussions as possible on the long-range. As you know from a lot of forecasts from other outlets I've posted this fall and my own winter forecast, most are expecting below-average precipitation for Northern CA this winter. Looking at the sea surface temperature anomalies we still have ENSO neutral along the equator and that blob of warm water south of Alaska. Similar to the dreaded 2013-14 season.
A couple of the things I have mentioned as being a little different is the cold water in the eastern Indian Ocean and the warm pool shifting farther off the West Coast. Signs that maybe we have more times of a retracted East Asian Jet Stream and the ridge sitting a bit farther off the West Coast. Maybe leaning towards a colder season than warmer. Right now we have warmer with the ridge right over the West Coast.
Currently, most long-range forecast discussions are not optimistic for storms in the next 2 weeks. Especially with the European model runs looking drier than other models. When going through all the model runs every day I look for trends or anything that stands out. We are still grasping at straws until we can get some storms on all the models in the one week window, but a few things to point out today from what I'm seeing.
Last Monday we look at the forecast for the MJO (Madden Julian Oscillation) which was showing activity moving through the Pacific. That seems to be on track. I said at the time that may initially mean a continuation of the ridge near the West Coast, which is what the models are showing for a week from now as seen above.
The GFS and several other models continue it into the Indian Ocean over the next 2 weeks. The European model does not. That could be part of the reason it is also not showing other pattern changes like some of the other forecast models are.
Right now with the ridge near the West Coast, we have a big cold trough in the Eastern U.S. with another shot of cold air coming this week. We could see record cold air and some snow. This pattern is consistent with the negative phase of the Eastern Pacific Oscillation. You can see that the GFS model below (and the Canadian) suggest that we could see a flip towards a positive EPO pattern beyond mid-month.
Here are the differences...
Negative EPO with the ridge near the West Coast and trough in the East.
Positive EPO with a trough near the West Coast and ridge in the East.
The other pattern that tends to happen with a warm NE Pacific ocean is the positive PNA (Pacific North American) pattern. We currently are in one but the GFS & some other models show a possible change beyond mid-month towards a negative phase of the PNA pattern.
Here are the differences...
Positive PNA pattern with the ridge over the West Coast and trough in the East like we are currently seeing.
Negative PNA pattern with the trough in the West and ridge in the East.
Those pattern changes would tend to line up with the MJO moving through phases 8-1 and into the Indian Ocean later in November. They are also similar to the pattern the GFS ensemble mean runs are showing from around the 20th into the last week of November.
21st
26th
The GFS and Canadian ensemble mean runs (which average together dozens of ensemble member runs) continue to show increased chances for precipitation starting the 20th which they have for several days now.
The European model is not showing the pattern changes above for the oscillations and stays fairly dry through the 26th. If the Euro is right we can throw the above discussion in the trash. But it's interesting that some of the other models have been showing these possible changes for several days now, and the teleconnection forecasts seem to line up with the pattern and precipitation forecasts. Even some of the GFS model runs the past 24 hours show some specific storms pushing in later in the month, and a stronger jet stream nosing into CA.
For now, these are some things we are watching. We will need the European model (historically one of the most accurate in the long-range) to get on board. Let's hope it does and that the MJO stays active and progressive and we can see a pattern change along the West Coast before the end of the month.
I thought you'd enjoy the above musings over another forecast that just says dry and mild for the next 10 days... Don't tell your friends it is going to snow until we get some storms into the 1-week window, this is not a forecast just an outlook rambling. I'll let you know when it's OK to let them know. ;)
Stay tuned...BA
P.S. This was written Sunday night. Looking at the forecast model runs Monday morning there are some European runs now suggesting similar pattern changes, and some storms possibly starting to dip this low as early as the 19th/20th. Fingers crossed...
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