Tahoe Weather Geek
Monday Feb. 2
The outlook for a rainy weekend is growing more likely today as forecast models are showing an “atmospheric river” pointed at Northern California starting Thursday and lasting through Sunday.
Unfortunately, the early forecasts also suggest that this storm is going to be a warm one.
It looks like the rain will begin by Thursday night, with snow levels initially quite high, probably around 8000 feet. As this first wave moves through we could see snow levels drop, perhaps to 7000 feet or a bit below, by Friday night.
After a brief break on Saturday it looks like another wave of precipitation is headed to NorCal by Sunday. Snow levels would probably be quite high with this system as well, at least at the start. They would likely fall as the cold front moves through, but it’s doubtful there would be much moisture left by then to deliver significant accumulations of snow below 7000 feet.
With a few days to go before the storm’s arrival, there is still a chance that the jet stream will remain north of Tahoe, and we’ll only get brushed by this storm, or that a pool of cold air will find its way into the flow, lowering snow levels a bit. But as of today neither of those scenarios look likely. More likely is that we will see several inches of rain at least up to 7000 feet between Thursday and Sunday.
Sunday Feb. 1
As the driest January on record for much of Northern California gives way to February, there are signs that the weather pattern is about to change. Not to be picky, but the change is not exactly what we’d been hoping for.
The ridge of high pressure along the coast is flattening today, and looks to shift inland later this week. That will allow storms coming in off the Pacific to make their way across Northern California rather than riding the ridge up into Canada and then back down into the interior of the U.S.
But after a few weak pulses mid-week bring clouds to the Tahoe Basin, the first chance for a real storm appears to be Friday or Saturday. A fairly strong low-pressure system brewing in the Eastern Pacific is forecast to move inland by then. But as of now, it looks like it will be a warm one. Most of the forecast models are showing snow levels around 8000 feet. One of the models suggests they could be a bit lower than that. In any case, most of the precip will be aimed north of Tahoe, and we will be on the southern edge of the jet stream.
Rain, of course, would not help the snowpack and it wouldn’t bring any solace to winter sports enthusiasts. But it might be the start of a wetter month that, hopefully, will include some snow.
Thursday Jan. 29
A January that is shaping up as the driest on record is about to end the way it began for the Tahoe Basin. The monthly snow-depth survey by the California Department of Water Resources today is likely to find the water content statewide at less than 30 percent, and the snow depth at Echo Summit, where it is measured manually, at next to nothing. It’s bleak, and there is no change in sight at the moment.
A weak trough over Southern and Central California is expected to move into Southern Nevada and Arizona by Friday, leaving mostly clear skies over the Sierra and the Tahoe Basin. Any remaining moisture should be far south of Tahoe in Mono County. Some brisk north winds may be in play Friday and Saturday as they follow the gradient from an area of high pressure north of Tahoe to the departing low in the south.
A weak low-pressure system moving through the Pacific Northwest Sunday and Monday should bring some precipitation as far south as Oregon and far Northern California but it is not expected to reach the Interstate-80 corridor.
A warming trend should kick temperatures back up above normal by Tuesday.
There are no major storms in the forecast. But there is a glimmer of hope for a change in the pattern around the second week of February. We will keep our eye on that scenario.
Tuesday Jan. 27
A weak low pressure system moving north from off the coast of Baja California will pass through the Central and Northern Sierra today, bringing light rain and a bit of high-elevation snow to the Tahoe Basin.
Snow levels are looking a bit lower in the latest forecast models, with snow possible down to about the shore of Lake Tahoe. But accumulations, if any, will be very light at that level, with maybe an inch of snow possible. Higher up, above 7000 feet, we could see three or four inches of wet snow by the end of the day. Snow totals are likely to be higher in the southern part of the Tahoe Basin than in the north.
A second wave of moisture on Wednesday appears likely to remain mostly south of Tahoe, and chances of precipitation later in the week appear to be fading.
An area of high pressure is forecast to rebuild by the weekend, ushering in a slow return to warmer temperatures.