Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Reno Nevada
318 am PST Sat Feb 28 2015
snow showers associated with a winter system will continue through
the weekend. Accumulating snow and difficult travel are likely in
the Sierra with lighter amounts and more localized travel issues in
western Nevada. This system will exit Sunday with a weaker system
expected Monday afternoon keeping temperatures below normal. Dry
conditions and a warming trend are expected later next week.
the core of an upper level low is beginning to settle across northern
California with a deformation area developing across the northern
Sierra. Snow levels are currently near 4500 feet with snow beginning
to mix in with rain around downtown Reno. Numerous chain controls
extend across the Tahoe basin including stretches of Interstate 80
through the Sierra to just west of Reno and Highway 395 north of Reno as
of 2am. Slick and icy roadways can be expected through the morning
where snow will continue to accumulate on Road surfaces.
Main impacts from snowfall will continue over the next 8-10 hours
across the Reno, Carson City, Minden region. These have been the
favored regions for banded snowfall to develop beneath the area of
deformation forcing and instability. Latest radar and satellite
trends coupled with short range hi-res hrrr model indicate main band
of snowfall positioned from Reno to Carson City through about 10am
then shifting south through Douglas, alpine, and northern Mono
County into the early afternoon. Additional snowfall accumulations
of 1-2 inches is possible through early afternoon in far western
Nevada with 2-4" possible at lake level. Winter weather advisories
will continue through late morning for far western Nevada and
through the afternoon across the Lake Tahoe basin.
Snow showers will shift south into Mono County through the afternoon
with 1-2 inches of snowfall possible through the Highway 395 corridor.
Cold temperatures aloft will allow for increased instability with
daytime heating which will produce the possibility of thunder
through the afternoon. Light snow showers will continue through
Sunday afternoon in Mono County with 6"+ possible along the crest.
Another disturbance follows suit on Monday but is showing signs of
splitting with the southern shortwave tracking off the central
California coast by Monday afternoon. This should present some
additional chances for snow showers mainly across the Sierra. This
does not appear to be a big snow producer by any means, but a few
additional inches of snowfall still could create some travel
impacts across Sierra passes late Monday afternoon and evening.
Long term...Tuesday through Friday...
models continue to lock in on a farther east (over eastern Nevada,
Idaho and utah) solution for an upper wave moving down the east side
of a Pacific Ridge. This will mean a most likely dry and cool north
flow on Tuesday for western Nevada and eastern California. Still, I
have left the slight chance of showers over Mono and Mineral
counties Tuesday as a nod towards the farther west solutions such as
the 27/12z and 28/00z operational European model (ecmwf). These showers may be able
to be pulled altogether soon if models continue to trend eastward on
the upper disturbance.
From Wednesday through Friday, guidance is in good agreement with a
ridge rebuilding inland across the Great Basin, resulting in dry
conditions and a gradual warming trend. Afternoon temperatures will
rise back to near average on Thursday before rising above average on
upper low directly over northwest/western Nevada is bringing
widespread -sn with IFR (locally lifr) conditions to far western
Nevada, with areas of MVFR ceilings/visible for the Lake Tahoe area and out
towards knfl/klol/khth (cigs). The short range high resolution model
(hrrr) indicates widespread -sn over western Nevada this morning as
the upper low slowly drops south. This should keep lowered ceilings/visible
and widespread terrain obscuration going in -sn this morning for
western Nevada, with areas of low ceilings/visible in the Tahoe area mainly
south of ktrk. Improvement is expected this afternoon for krno/kcxp
as the main area of snow shifts south. Pavement temperatures will
remain near freezing through middle morning for far western Nevada and
the northern Sierra so untreated surfaces will see a light
Farther south into Mono and Mineral counties, worsening ceilings/visible are
likely to move in later this afternoon and tonight as the upper low
drops south. Light snow accumulations for terminals in Mono County
are likely, with a possible light accumulation out in Mineral and
southern Lyon counties below 5000 feet tonight. Out in the basin and
range (klol/knfl), accumulations are unlikely with the main issue
lowered ceilings and higher terrain obscuration this morning. Snyder
Nevada...Winter Weather Advisory until 4 PM PST this afternoon nvz002.
Winter Weather Advisory until 10 am PST this morning nvz003.
California...Winter Weather Advisory until 4 PM PST this afternoon caz072.
For more information from the National Weather Service visit...
http://weather.Gov/Reno (all lower case)