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941
FXUS65 KREV 192111
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
211 PM PDT Tue Mar 19 2019

.SYNOPSIS...

Mild conditions continue today with increasing clouds ahead of an
approaching storm system. This system will move slowly east and
bring cooler conditions with valley rain and mountain snow showers
tonight through Thursday. A few thunderstorms are also possible
Wednesday afternoon and evening. After a short break Thursday
night and Friday, another round of showers is possible Saturday.


&&

.SHORT TERM...

No major changes to the overall forecast thinking today. Cloudless
skies from the last few days are being replaced by increasing
high level clouds this afternoon ahead of an incoming cold front
currently located off the California coast.

Overall this is a pretty weak storm, but will have some
thunderstorms embedded creating the potential for isolated areas
of heavier snow/rain. Minor snow impacts are probable along the
higher passes tonight through Wednesday night with light snow
accumulations possible down to around 5500-6000 feet Wednesday
night. Western Nevada can expect on and off rain showers over the
next 48 hours with bands of moderate to heavy rain possible. Some
areas in western Nevada could pick 0.5-1+ inch of rain but these
areas are not expected to be widespread.

As this storm moves into the region it will continue to weaken and
the upper level trough will continue to become more negatively
tilted. There is also very little in the way of jet stream winds
associated with this storm. What does that mean for us? It means
the flow aloft will predominately be from the southeast creating
less orographic forcing then usual. This also means much of the
precipitation with this system will be from upper level diffluence
and convection instead of our usual orographic forcing. This
makes it very difficult to pin down exactly where the heaviest
precipitation will be. Some current model simulations have this
area directly over the Reno/Carson area, but it could just as
easily be 50 miles farther east.

It will be pretty breezy in western Nevada this evening through
through tomorrow morning as the surface gradient strengthens. Most
areas should max out around 30 mph gusts, but some gusts to 45 mph
are possible in wind prone areas like Walker Lake.

By Thursday, showers will become weaker and more isolated in
nature as weak shortwave ridging briefly develops ahead of the
next system. Most of the day on Friday should be precipitation
free, so if you`re looking for a snow/rain free window to cross
the Sierra, Friday afternoon may be a good opportunity. -Zach



.LONG TERM...Saturday into next week...

A colder and quick moving trough is poised to move through northern
California and Nevada Friday night into Saturday. This shortwave
looks to have a weak subtropical moisture tap which will provide
mountain snow and spillover rainfall across western Nevada valleys
through Saturday afternoon.

The quick storm motion should limit snowfall accumulations and
mainly in the scope of a few inches above 6500-7000 feet Friday
night with snow levels falling near 5000 feet by Saturday morning.
Snow may have difficulty accumulating on roadways but conditions may
still be slick and slushy across NE CA and the Tahoe Basin. For
western NV, there is a low chance for slick travel conditions above
5000 feet Saturday morning but should be mainly rain with some
periods of rain/snow mix through the day Saturday. Rain amounts of a
few tenths are looking possible for Pershing and Churchill counties
with generally less than a tenth across the Sierra Front.

Most shower activity diminishes by Saturday evening with a break in
the weather through at least Monday when a cut-off low develops
offshore and looks to provide rain and mountain snowfall along with
gusty winds. Timing and track uncertainties are higher than average
due to the weak steering flow associated with cut-off lows. However,
did increase precipitation chances and winds early next week as the
storm begins to push into northern California. Fuentes

&&

.AVIATION...

An incoming low pressure system will provide widespread mountain
terrain obscuration from increasing clouds along with periods of
MVFR/IFR conditions at the terminals as precipitation begins to
move into the Sierra tonight after 07-08z. Snow levels are expected
to be in the 6000 to 7000 foot range. Snow accumulations of 1-3
inches are possible around KMMH tonight into Wednesday morning, with
an inch or two possible at KTVL. Increasing instability Wednesday
afternoon will create the possibility of a few thunderstorms as
well, most likely well north and east of KRNO.

Gusty east and southeast winds across the Sierra ridgetops are
expected to peak through this evening with areas of turbulence
possible along and downstream of the Sierra. Winds at the surface
will remain breezy from a Gerlach-Lovelock-Fallon line where
northeast winds around 10-15 kts are possible through Wednesday
morning. Southerly flow across Sierra terminals and KRNO/KCXP could
see gusts in the 25-30kt range this evening through Wednesday
morning before weakening through the afternoon. Fuentes

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.

&&

$$

For more information from the National Weather Service visit...
http://weather.gov/reno