Update Sunday Evening:
The model runs this afternoon were much more progressive with the low next weekend. That would push precip into the Tahoe basin for most of the event Saturday through Tuesday. The 12z European was very impressive with 3-5 feet for the mountains. We will be following this closely all wee.
From This Morning:
High pressure builds in along the West coast this week bringing dry conditions and mild temps. The patter begins to change by the end of the week with low pressure looking to setup off the West Coast next weekend into the following week. That could bring significant amounts of precip to Northern CA and snowfall to the Sierra.
The snow levels didn't come down yesterday until most of the precip had moved East. Above 8000 ft. only an inch or two being reported. Above 9000 ft. Mt. Rose is reporting 3 inches. The other resorts with elevations above 9000 are not reporting anything yet. My guess is that on the West side of the basin above 9000 ft. saw 3-6 inches if 1-3 is being reported on the East side. Either way that is too high for anyone to really care.
This is the slowest start to the season we have seen for the higher elevations in several years. Looking at Squaw's snowfall tracker they picked up 18 inches so far this Fall as of Friday with the 5 inches that fell Thursday night. The last time we had that little as of the 21st was 19 inches in 2009. 2010 had 73 inches, 2011 had 24 inches, 2012 had 86 inches, and 2013 had 33 inches as of the 21st. Hopefully we will start to catch up starting next weekend.
High pressure is building along the West coast and will stay there are will keeping us dry and mild. Highs will be in the 50's by midweek with nice weather for the Thanksgiving holiday.
By Friday the pattern begins to change with high pressure shifting East. Low pressure spinning in the Eastern Pacific will slowly make its way towards the West Coast by the end of the week, setting up off the coast. The latest forecast model runs are in decent agreement with the setup of the pattern by next weekend. The low pressure system may set off the coast for several days and pull in moisture from across the Pacific, aiming it at Northern CA next weekend into the beginning of the following week. This may result in a lot of precip for Northern CA.
The problem for us may be the orientation of moisture flow on the East side of the low. Many times in this type of a setup that the models are suggesting the Southerly winds on the East side of the low prevent precip from pushing over the crest into the Tahoe basin. While the rest of Northern CA picks up several inches of liquid, most of the precip may stay on the West side of the crest next weekend. Snow levels will be high as well.
Eventually the system will push inland which is when the heavy precip and colder air would push into the Tahoe basin. The forecast models show this happening by Monday the 1st into the 2nd before the system clears to the East by the 3rd. This is on the 1 week away borderline so confidence is only moderate because of the model agreement a week out. Tomorrow will be 5 days from the start of the storm so we can start to look at potential snowfall amounts for the mountains.
Here is a look at the storm sitting off the coast next weekend the new updated GFS model.
and the total precipitation forecast on the same model through Tuesday the 2nd.
Here is the Canadian model forecast for total precip for the same range. Notice the much higher precip totals to the NW of the lake where it falls next weekend with the Southerly flow before pushing into the basin.
The PNA pattern will shift to a negative phase next weekend which is a West Coast trough pattern as you can see here on the GFS forecast.
The GFS long-range forecasts hold this pattern with more storms diving into the West Coast the first week of December. The CFSv2 model sees this as well showing over 200% of average precip over much of CA through December 8th.
It keeps this pattern through mid-December before rebuilding the ridge along the West Coast and drying us out the 2nd half of December. The European model runs show the ridge building off the coast the first week of December after the storm next weekend.
This is all speculation of course as the long-range models accuracy is not that great. Hopefully the pattern stays active into December.