Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Reno Nevada
332 am PST Wednesday Nov 25 2015
Scattered to numerous snow showers continue today with low
pressure over the region. Another wave will move through bringing
light accumulations this afternoon. Then...isolated to scattered
snow showers and very cold temperatures through the weekend. Low
potential for another wet and cold system early next week.
Road conditions have deteriorated overnight as temperatures
dropped and wet surfaces froze over. Many secondary roads are very
slick with a fine sheen of ice compacted to the surfaces. Driving
conditions for the morning commute should prove difficult; please
allow extra time to get to your destinations.
Light snow continues to fall in the Sierra as westerly flow lifts
along orographics. Also, some Narrow Lake bands have formed off of
Lake Tahoe and Pyramid Lake. The Tahoe band has been most
persistent from Incline Village through Lakeview and northern
Carson City. A smaller band was occurring over Spooner Summit
along Highway 50. It is difficult to say how much has fallen, but
3 to 6 inches is a decent first guess. Travel will be hazardous
through these areas with More Lake effect snow on the way. The
band off of Pyramid Lake has not been present as long as the Tahoe
bands and mainly falling just northeast of Nixon along Highway
447. These bands will continue and others may form this morning as
westerly flow moves lake moisture up and over terrain features.
Bands around Pyramid Lake will likely intensify later this morning
and early afternoon as winds shift more out of the northwest;
impacts can be expected from Nixon to Interstate 80 near Fernley.
Also, a wave is working its way around the backside of the upper
low that has stalled over northern Nevada. This wave will push
through western Nevada impacting the Reno/Carson metropolitan areas
between 10am and 2pm. Model moisture has increased with this
feature over previous runs and may result in a quick 1-2 inch
accumulation of snow today. Snow will persist over northern Washoe
County and in the Surprise Valley. Another 2-4 inches of snow will
be possible closer to the Oregon border.
The upper low meanders west Thanksgiving day, but most of the
moisture will have left the region. Still, western Nevada can
expect an isolated shower through Friday night. Upsloping along
the Sierra will increase shower coverage to scattered. While
showers will continue, accumulations will be minimal due to the
limited coverage and intermittent duration.
Temperatures remain cold through the Thanksgiving Holiday and end
of the week. Lowered low temperatures for the northern zones
trending more towards raw model guidance. Snow cover will aid in
keeping temperatures lower than usual resulting in lows around 10
degrees for the Surprise Valley and northern Lassen/Washoe
counties. Elsewhere, hard freezes can be expected with lows in
the upper teens for western Nevada and around 10 for Sierra
valleys. Highs will struggle to reach freezing, today and
Long term...Saturday to Wednesday...
The core of a cold upper low will remain over the northern Sierra on
Saturday before finally ejecting eastward on Sunday. This low will
maintain cold temperatures along with the potential for light snow
showers across the Sierra and even into portions of far western
Nevada. The last several model runs have been consistent with this
feature but have trended a bit lower on snowfall amounts. A few
inches of snowfall accumulation still look possible mainly for the
Sierra Friday evening into Saturday morning. Although accumulations
should remain on the lighter side, it may still be enough to impact
travel for the end of the Holiday weekend.
Attention then turns to the large scale pattern across the Pacific
for early next week. Model guidance suggests little to impede the
storm track into the West Coast. The differences amongst model
guidance appear to be more of a matter of when these systems push
onshore. The GFS is by far the wetter solution with a series of high
moisture systems as early as Monday while the ec remains dry and
brings in a storm by the second half of the week. Will maintain
precipitation chances in the forecast through early next week but
still too far out to judge the character of these systems at this
Mainly VFR conditions today with widespread snow showers expected
through the day. Could see short periods of IFR visibility/ceilings within
snow shower activity. Additional snowfall of up to an inch possible
at krno with 1-3" for the Sierra terminals including ktrk, ktvl,
The Carson City and Minden terminals have the potential of receiving
heavy lake effect snow bands off of Lake Tahoe through this
afternoon. Any snow bands that set up over the terminals have the
potential of seeing intense snowfall rates of 2-4 inch per hour.
Rapid runway accumulations and near zero visibility are probable
with lake effect snowfall. Fuentes
Nevada...Winter Weather Advisory until 4 PM PST this afternoon nvz005.
Winter Weather Advisory until 4 PM PST this afternoon nvz003.
California...Winter Weather Advisory until 4 PM PST this afternoon caz070.
For more information from the National Weather Service visit...
http://weather.Gov/Reno (all lower case)