Lake Tahoe Snow!
Finally it looks like we have a couple of decent storms brewing in the Pacific which may affect the Lake Tahoe basin and the High Sierra. At 6500 feet (my home) it is currently raining with a mix of heavy wet snow but it is snowing at the resorts and we should see 4-6 inches today through early tomorrow. Then a much more potent system appears to be forming and will possibly bring significant snow Friday night into Saturday mid-day. How much will fall from this system is in question but after each model run it looks more and more impressive! Right on the heels of that storm is another which may be much colder and more impressive dumping possibly 1-2 feet of snow at the resorts and 10-14 inches at lake level. This event could last from Sunday- Tuesday. It then looks like Lake Tahoe will dry out but the active pattern should continue through the next 15 days with the most impressive storms looking like day 10-15 on the extended. Stay tuned!
Here is the NWS forecast statement for 1/22/09:
Area forecast discussion
National Weather Service Reno Nevada
350 am PST Thursday Jan 22 2009
a relatively narrow but heavy band of rain is moving slowly across
northern and central California this morning as an upper trough makes its
way onshore. This band of heavy precipitation is being fed by a juicy
subtropical connection off the Baja California coast. Snow levels are currently
around 8500 feet or so...which is pretty normal for this type of
subtropical tap. Only the highest mountains in our area will
see any snowfall with this storm...and even then it should be pretty
wet and heavy. Snow levels are expected to remain high...generally
above 8000 feet through Friday...before finally coming down by
Friday night as we get into some colder air. No winter statements
expected at this time...due to the high snow levels.
The elongated trough coming into California this morning has split into two
main vorticity maxima...with the shortwave currently northwest of the Bay
area being the one of our concern. This wave will lift through
northern California and into the far northwest corner of Nevada by this evening.
As this wave pushes inland...the stream of heavy precipitation we are
seeing on the cal radars will push east across the higher elevations
through the day and scattered showers across western Nevada.
There is some good diffluence aloft lifting the deep moisture... and
models are indicating a band of 700mb frontogenesis from Truckee to
Lovelock later this afternoon and evening. This low level forcing
will create a nice band of showers across the Interstate 80
corridor...with periods of moderate to heavy rain possible. Both GFS
and European model (ecmwf) indicating this band of heavier precipitation setting up across the
forecast area...so bumped up probability of precipitation and quantitative precipitation forecast for this afternoon and
evening in the western Nevada valleys.
Late tonight and into early Sat morning we will see a Little Break
in the action as we get some weak shortwave ridging...but with the
abundant moisture still streaming off the Pacific and into our
area...scattered showers are not out of the question.
By Friday...another upper level low will drop in right behind...with
the nose of a 100kt jet pushing across central California and into the
Sierra. On top of that...a very nice looking diffluent left exit
region will setup right over the Tahoe area. Latest models are
coming up with some impressive quantitative precipitation forecast values for the time period
between Friday night and early Sat morning as we get a shortwave
lifting through norcal...interacting with the dynamic jet. This is
plausible to happen with this deep subtropical moisture tap setup.
So...upped up quantitative precipitation forecast and probability of precipitation for Friday night and Sat as we get this jet
maximum moving into our area. If models continue to show this period of
enhanced precipitation...the forecast may need to go up even more. By
Friday night...snow levels will begin to lower from 8000 feet down
to near lake level by early Saturday morning...which could cause
some travel concerns for the Sierra passes Friday night and
Long term...Sunday through Wednesday...
models continue to drop energy down along the West Coast for Sunday
and Monday developing a deep positively tilted trough/closed low from
the northern rockies back across California. The GFS...Canadian...
and ec continue to differ in details with respect to location of the
upper low and timing.
Generally for Sunday and Sunday night the upper low should extend
across northern California with the GFS further west...rotating the low
system off the coast... and the ec inland. At any rate snow will
increase across the Sierra Sunday and continue through Monday. By
Tuesday models cut this deep low off from the northerly branch of
the jet sagging the primary feature west of Southern California. This would
decrease precipitation across the Sierra Tuesday to scattered
showers. By Wednesday although again the details differ...northern
California and western Nevada should be under northerly flow aloft as the system
Overall expect snow in the Sierra Sunday diminishing to scattered
showers by Tuesday with Wednesday and later in the week generally
dry. Snow levels will start out around 5000 feet so Sierra
precipitation should be all snow. Over the period from Sunday
through Monday night there could be 6 to 10 inches or so of snow at
lake level with a foot or 2 at higher elevations of the Sierra. Will
have to keep an eye on storm organization to determine whether any
watches or warnings will be needed. At this time it looks like the
best chance for heavier snow would be Sunday associated with the
cold front...with generally light snow for the the remainder of the
early week period.
For western Nevada valleys...snow levels will start at around 4000
feet up toward the Oregon border to 5200 feet or so in the
Reno-Carson areas to 5500 feet further east. The best chance for
valley snow will be associated with the cold front passage. The ec
drops the cold front through western Nevada late Sunday and Sunday
night. The GFS brings it through a little earlier...Sunday afternoon
and early Sunday night. Except for Surprise Valley would not expect
more than a dusting to an inch or less for the valleys.
The coldest day of the week should be Monday but temperatures will
just be 5-10 degrees below normal in most areas before moderating
back close to normal later in the week. Jah