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Area forecast discussion 
National Weather Service Reno Nevada
313 am PST sun Nov 29 2015


A weak high-pressure ridge will lead to strengthening inversions and
deteriorating air quality the next few days. A modest winter
storm will impact the region Thursday into Friday with travel
impacts in the Sierra expected.


Short term...

High pressure building over the west will bring warming
temperatures aloft with forecast soundings indicating strong
inversions present for valley locations. This will lead to
mountain sites warming much quicker over the next several days,
while lower elevation valleys will be slower to warm. The
inversions will bring poor mixing with deteriorating air quality
likely through midweek. Anyone with sensitivities to particulate
matter in the air should try to limit strenuous outdoor
activities, or in extreme cases, stay indoors. You can monitor
conditions at www.Airnow.Gov and also check with your local air
quality agency for the latest.

Overnight low temperatures are once again quite chilly early this
morning as clear skies and calm winds are allowing for excellent
radiational cooling. Most sites in the Sierra are reporting single
digit to below zero readings and even the valleys in western
Nevada are in the teens to single digits. These very cold
temperatures create concerns for the homeless and other at risk
groups in addition to pets - take shelter if possible. The cold
low temperatures will gradually moderate over the next few nights,
but will remain well below normal.

A weak wave will bring clouds to the Sierra and western Nevada on
Monday, but no precipitation is expected. Warm air advection could
bring light precipitation to northeast California Tuesday night
into early Wednesday, but any accumulation will be minimal. The
cold front and stronger part of the system arrives on Thursday,
see the long term for additional details. Dj

Long term...Wednesday through Sunday...

Confidence is increasing in a modest winter storm impacting the
Sierra on Thursday. Models have shown good agreement over the past
several runs in bringing this system into the Sierra, however the
main uncertainty is timing as there is about a 6-12 hour variation
for precipitation onset between the GFS and European model (ecmwf). The bottom line
at this point is to expect accumulating snowfall as early as late
Thursday morning for Sierra passes. Travel impacts will likely
persist through Friday morning.

Only minor adjustments in the forecast with the overall character of
this winter system remaining on track. That is, a quick moving
system with an orientation favoring precipitation shadowing and a
brief period of spillover into western Nevada by Thursday
afternoon/evening as a cold front passes. Strong and gusty winds are
also expected ahead of the front early Thursday with widespread
gusts of 45 miles per hour and locally higher through the afternoon. The north-
south pressure gradient would produce strong winds across the Sierra
and especially through the I-580/hwy395 corridor through the
Sierra front.

Timing the start of snowfall across the Sierra still needs some
refinement but could see snow beginning as early as late Thursday
morning. Snow levels will start near 6,500 and drop below 5,000 feet
across western Nevada by Friday morning as the front passes. This
does not look like a favorable set-up for western Nevada to see
large amounts of rain or snow as shadowing should keep the bulk of
the moisture along the west slopes and near the crest. Overall up to
a foot of snowfall looks reasonable along the Sierra crest with
shadowing and lesser amounts along the east slopes.

The system pushes through quickly on Friday with most showers ending
by late Friday afternoon. A few weaker brush by systems will keep
chances for showers in the forecast through Sunday, but they should
remain light and confined across northern areas of California and
Nevada near the Oregon border. Fuentes



Light winds and VFR conditions will prevail across the terminals
through early next week. Shallow freezing ground fog may be
possible in the vicinity of ktrk this morning, but coverage should
remain off of the airfield closer to martis creek. Fuentes


Rev watches/warnings/advisories...


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