Heavy Snow in Nevada, March 28 to 29, 2016

Area Forecast Discussion
National Weather Service Reno NV
238 AM PDT MON MAR 28 2016

.SYNOPSIS...
A strong cold front will continue moving through the Sierra and
Western Nevada this morning. Snow showers will occur behind the
front today with the heaviest band expected along I-80 this
morning. The upper low will continue to influence area weather
into Wednesday as it slowly pulls east with scattered showers and
cold temperatures. Mild and dry weather returns for late week.

&&

.SHORT TERM...
The snow event is getting underway as I write this. The surface
cold front is now along a line from Portola to Palomino Valley and
then almost to Highway 50 in Churchill County. Showers have
developed west of the crest and are moving east along the
boundary. Currently, temps are mild from I-80 southward and around
40-45 degrees, but are in the 30s behind the front. With precip
now moving in along I-80, areas below 5000 feet will start as
rain, but expect it to change to snow north of Highway 50 by 6 AM.

As for the band, the NAM/GFS/HRRR are hitting the I-80 corridor
the hardest. The NAM actually shows close to 1" of water in the
Reno/Sparks North Valleys. This is likely overdone, but 1/2" seems
plausible. With the cold air coming in, this will mostly be snow
and 3-6" of snow seems likely along the I-80 corridor above 4500
feet. Lighter amounts farther south away from this main band.
Roads will be slick this morning near I-80 and also into eastern
Plumas County due to the snow. Be prepared for a longer than
normal commute and the advisories will continue as is.

One thing to note is that the band doesn't make it to southern
Lyon County until late morning. If this occurs, any snow that
falls will melt on impact, especially on the roads due to the
higher late March sun angle.

As we move into the afternoon, the cold pool moves overhead and
expect snow showers to continue across the area, but little
accumulation due to solar heating. Any lake effect for Pyramid
Lake looks less likely today as models now show the winds being
more Northeast, and also 30+ kts at 700 mb. This is in addition
to the diurnal minimum in LES during the afternoon. Still, plenty
of showers will be around in the instability.

The upper low then only slowly pulls away into Wednesday. A
northeast flow will continue on the backside Tuesday and
Wednesday. Showers look more likely Tuesday as the cold pool
remains close enough. Wednesday the instability is weaker and more
south of I-80 so just have a slight chance of showers there.
Temperatures will slowly moderate from today's much below average
readings, but remain below normal into Wednesday. Wallmann

.LONG TERM...Thursday through Sunday...

Only minor changes were made as the previous forecast thinking is on
track. Temperatures will begin to warm Thursday although northeast
flow aloft will persist for one more day and keep the warmup slow
initially. This will be the poorest day for mixing as surface
warming will not keep up with warming temperatures aloft, resulting
in moderate inversions. Friday, we expect temperatures to jump 7-10
degrees with a better mixing profile.

For the weekend, instability and weak shortwave may be sufficient
for isolated showers (probably not much more) across far northeast
CA and northwest NV. Given the northern track of this shortwave,
showers in the Sierra are unlikely and we have removed the mention
there. Otherwise, it is going to be an unseasonably mild weekend
with highs in the upper 50s to around 60 Sierra valleys and mid
60s to low 70s western NV valleys.

&&

.AVIATION...

A cold front moving southward into western NV early this morning
will continue to drop south and allow colder air to settle into the
I-80/Hwy 50 corridors. Meanwhile, instability continues to increase
as upper low drops into the region with band of rain and snow
intensifying near and north of I-80. Some models are indicating some
impressive bands of precipitation developing through 15z and right
now, it appears that zone will be very close to where it is setting
up currently which would have bigger impacts for KTRK-KRNO-KLOL.

Temps and dewpoints are currently too warm for much accumulation
below 5000 feet and this will likely remain the case outside of
heavier bands of precipitation even though we do anticipate a
changeover to all snow during the morning hours. So the key to
getting accumulation on area runways will be location of most
intense snow bands prior to 16z. Light accumulations are already
occurring at KTRK and we will just have to monitor radar trends for
KRNO-KLOL. The band is forecast to slide south into Mono-Mineral
County this afternoon and evening with some light accumulations
possible at KMMH near or after sundown. Right now, due to the timing
of the band (later in the morning) at KTVL-KCXP-KNFL, accumulations
look minimal. There could still be some brief slushy accumulations
if snow showers become sufficiently heavy. But any accumulation
will melt quickly once the snow showers pass.

Otherwise, expect periods of IFR/MVFR CIGS/VSBY during snow showers
with terrain obscurement, especially close to the Sierra. Hohmann

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 11 AM PDT this morning NVZ003-004.

     Winter Weather Advisory from 7 AM this morning to noon PDT today
     NVZ001.

CA...None.
&&

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