Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 191127
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
327 AM PST Mon Feb 19 2018

.SYNOPSIS...

A cold low pressure trough will remain over the region this week
with below normal temperatures and periods of snow showers today and
again on Thursday. Windchill temperatures will be bitter in the
backcountry today and tomorrow.


&&

.SHORT TERM...

Welcome back Winter! Cold unstable air continues to pour into the
region from the north as a large scale trough of low pressure
settles into the Great Basin. A weak disturbance, currently
around Pyramid Lake, is moving south with a band of light snow
developing along it. This band of snow showers could bring an
addition 0.5-1.5 inches of snow to areas around and north of Reno
over the next few hours.

Snow that fell yesterday around the Reno/Tahoe area melted as it
contacted road surfaces and in some areas the sun re-appeared
before sunset and started to melt snow on the ground. These melted
areas are now frozen and could keep the driving conditions
dangerous again this morning. This will especially be the case if
additional snow falls on top of the ice making it much slipperier
than the snow would be by itself.

Bands of Lake effect snow are evident on radar from both Lake
Tahoe and Pyramid Lake this morning. Good low level instability
and light unidirectional winds today should keep lake effect snow
going through most of the day today. This could bring an
additional 3-6 inches of snow to areas 10-20 miles south-
southeast of Tahoe and Pyramid lakes.

Very cold temperatures are expected the next few days, especially
with snow cover in some areas that will increase radiative heat
loss overnight. Today and tomorrow temperatures will struggle to
reach near freezing in most areas. Overnight low temperatures will
be especially cold with lows throughout the area expected to be in
the low teens with colder valley locations likely dipping below
zero. Temperatures will start to warm a little by Wednesday with
highs in the lower valleys pushing back to around 40 degrees.
-Zach

.LONG TERM...Thursday through next week...

Cold low pressure remains over the Western U.S. through the end of
the week with additional shortwaves dropping through the Pacific
Northwest and into Northern CA/NV. These shortwaves will bring
additional reinforcing cold air into our area, along with increased
chances for snow. Snow levels will be at all valley floors for the
next 7-10 days.

The next shortwave trough/jet max drops in on Thursday, bringing
another cold front into the region. Forecaster confidence continues
to rise with regard to seeing accumulating snow along the cold front
for almost all of our forecast area. Not expecting to see any heavy
amounts, but light snow amounts from 0.5-2 inches are likely
Thursday and Thursday night as this wave moves through the region.
Cold air aloft will increase the instability, so we should see some
heavier convective bands that will get a few areas with localized
heavier amounts. Gusty winds and light powdery snow will also lead
to blowing snow and low visibilities when the front moves through on
Thursday. Plan on travel delays and impacts due to snow and blowing
snow in the Sierra, along with snowy travel impacts to the Thursday
evening and Friday morning commutes in western Nevada.

Another shortwave moves through the Pac NW on Saturday, although
this wave is trending further north and may just skim across the OR-
NV border without dropping further south. The ridge over the Pacific
retrogrades slightly as we go into next week, which could allow for
even more shortwaves to drop along the Pacific Coast and potentially
bring more snow to the region and more reinforcing cold fronts.

If you have any travel plans into next week, make sure to keep up
with the latest forecasts. For more on the potential for active
weather into March check out the Week 2 Outlook below. -Hoon

.Week 2 Outlook...Feb 27th-Mar 4th...Issued 3am 2/19

After another very dry winter in the Sierra, conditions are
finally starting to look favorable for a transition to a more
stormy pattern. The high pressure that has been entrenched along
the west coast is finally forecast to retrograde westward likely
allowing storms from the Gulf of Alaska to again make their way
into the region. This will also be a cold pattern for the region
with below average temperatures likely to persist into early
March.

Next week into next weekend we could see multiple more cold
slider type storms with light to moderate addition snow amounts.
By the beginning of March there is a decent possibility that the
high pressure in Pacific will continue to retrograde allowing
stronger storms coming out of the Gulf of Alaska to move over the
Pacific before making it into the Sierra. This could allow the
first real chance of seeing strong cold storms into the region
than we did all "winter".

While there is never a guarantee for strong storms as far out as
week 2, the pattern is beginning to look favorable, and after
another record-breaking dry winter in the Sierra this would be a
welcome pattern change. -Zach

&&

.AVIATION...

Scattered snow showers are expected today, with lake effect snow
bands developing off of Pyramid Lake and Lake Tahoe to the
southeast. This will likely bring minor accumulations to KCXP,
KTRK, KTVL, and KMMH up to a couple inches. Conditions will
generally be VFR/MVFR, although if that lake effect band off of
Tahoe moves over KCXP or KTVL we could see IFR conditions under
the heavier snow bands.

Conditions will improve on Tuesday although cold and brisk, with
clearing skies and VFR conditions. -Hoon

&&

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

$$

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



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