Area Forecast Discussion
Issued by NWS Reno, NV
FXUS65 KREV 271027
Area Forecast Discussion
National Weather Service Reno NV
327 AM PDT Thu Oct 27 2016
Two wet storms will affect the Sierra and western Nevada this
afternoon through the weekend. The first storm tonight into Friday
is warm and wet with the second storm Saturday night into Sunday
being colder. An active weather pattern is expected to continue into
Main change to the forecast this morning were to increase winds
today ahead of the moisture, especially along the higher terrain.
The Sierra crest is already gusting up to 70 mph this morning. A
lake wind advisory has been issued through early afternoon, but
winds should drop off fairly quickly as moisture spills into
Very sharp trough off the west coast with a strong north-south
oriented jet is pulling sub-tropical moisture from Hurricane Seymour
into southern California. Light showers will be possible this
morning in the northern Sierra before the bulk of the moisture
begins to impact the southern Sierra later this evening into Friday.
PWAT values will be near to above October record values for the
Sierra and western Nevada as sub-tropical moisture moves through the
region. The wind direction isn`t optimal for spillover
precipitation, but the depth and magnitude of the incoming
moisture should allow precipitation to quickly spill into western
Periods of very heavy rain are expected tonight into Friday with
increasing concern for rock and mudslides near recent burned areas.
Through Friday evening the Sierra crest could easily see 1.5-2.5" of
precipitation with western Nevada easily picking up 0.5-1.0".
Periods of hazardous travel should be expected in and around the
Sierra the next few days. Late Friday night through early Saturday
afternoon will be a break between storms which could be a better
time to travel. However, right along the Sierra crest may stay
showery through the weekend.
With the warm origin of the moisture snow levels are expected to
start very high around 10000 to 11000 feet. By Friday snow levels
will be closer to 9000 near the end of the first round of heavy
precipitation and continuing to fall to below 8000 feet by Saturday
night. Snow levels will also be highly variable easily being dragged
down by 1000 feet in heavier bands of precipitation.
.LONG TERM...Sunday through Wednesday...
Another storm will move into the region Sunday, bringing valley rain
and mountain snow along with gusty winds. Snow levels will start out
around 7000-8500 feet Sunday morning, then dropping down to between
6000-7000 feet Sunday afternoon. There are still some slight
differences in the timing of main precip on Sunday, with the GFS
coming in 3-6 hours earlier than the ECMWF. Either way, snow will
likely start accumulating at pass level around Tahoe and down into
Alpine and Mono Counties late Sunday morning through Sunday Night.
Snow amounts of 8 to 18 inches will be possible during this time for
elevations above 7000 feet. Down around Lake Tahoe level, snow
levels may come down by Sunday night as precipitation begins to
taper off. It`s possible that we could see some light snow
accumulations at lake level, although generally less than a couple
inches. Anyone with travel plans in the Sierra Sunday through Monday
morning should be prepared for winter driving conditions and slow
Rain will spillover into the valleys of western NV and northeast CA,
with another 0.10-0.25" into western NV. Higher rainfall amounts are
likely in the valleys of northeast CA with up to 0.50" possible on
Sunday. Lastly, winds will be increasing on Sunday as well, with
gusts up to 35 mph and ridge gusts near 80 mph.
As we go into Monday, a few showers may linger around, but the main
trough will be pushing out of the area as shortwave ridging builds
overhead. Temperatures for Halloween will be a bit below normal, but
not anything scary cold. Recent models have been trending further
south with the track of the shortwave entering CA on Tuesday,
although it`s possible that we could see some light precipitation in
the Sierra on Tuesday as the shortwave splits into Southern CA.
Forecaster confidence is low beyond Monday, but it`s likely that the
pattern will remain unsettled through next week. Hoon
Gusty winds are expected today with gusts up to 20-30kts late this
morning and into the early afternoon. Low level wind shear may be
possible this morning, before the winds start to mix down around
midday. Sierra ridge winds are already gusting at around 60kts, so
low level turbulence is likely downwind of the Sierra through
Friday. A few showers will start to push into the Sierra by this
afternoon ahead of the next storm system, but no restrictions to
CIG/VIS are expected through this afternoon.
A wet/warm storm system moves in this evening through Friday with
abundant clouds, moderate to heavy rainfall and restrictions to
CIG/VIS likely at all area terminals. MVFR CIG/VIS is likely tonight
and into Friday, especially for KTRK, KTVL, and KMMH as the heaviest
precipitation moves into the region.
Another storm is set to move in this weekend with additional impacts
to aviation as well. Hoon
NV...Lake Wind Advisory from 8 AM this morning to 5 PM PDT this
afternoon for Pyramid Lake in NVZ004.
Lake Wind Advisory from 8 AM this morning to 5 PM PDT this
afternoon for Lake Tahoe in NVZ002.
CA...Lake Wind Advisory from 8 AM this morning to 5 PM PDT this
afternoon for Lake Tahoe in CAZ072.
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