Heavy Snow in Nevada, March 30 to 31, 2024

Area Forecast Discussion
National Weather Service Reno NV
256 AM PDT Sat Mar 30 2024

.SYNOPSIS...

Periods of mountain snow with a valley rain and snow mix will
continue through the holiday weekend. This will impact travel,
especially over Sierra mountain passes. A few days of warmer and
drier conditions start the work week. The later part of the week
will see the focus shift to increased precipitation chances and a
period of cooler temperature with the next Spring storm.

&&

.DISCUSSION...

Today through Sunday:

March is definitely going out like a lion. His mighty paw sweeping
over the Sierra and western NV through the Holiday weekend.  Now
lets get to the short and skinny about this early Spring system
creating all the fuss. Most recent GOES-West channel-15 imagery
shows the low pressure system rotating cyclonically just off-
shore the central CA coast. Its current location is enabling a
south-southwest upper flow to tap into Pacific moisture that
spreads north and northeast into the Sierra and western NV. Hi-
Res guidance projects that the low center, which is now embedded
in the base of the broader upper trough, will swing south off-
shore the central-southern CA coastline the next 36-48 hours. A
stronger secondary low pressure circulation that spins- up today
over east-central CA will then lift east-northeast into west-
central NV later this afternoon through Sunday morning. This
Nevada low-like system will wrap low-mid level moisture across
the region, increasing shower chances across the Basin and Range,
the central Sierra to include the Lake Tahoe Basin, the eastern
Sierra/Mono County.

Precipitation: Today will see mostly showery conditions across the
Sierra and western NV. With snow levels gradually increasing to 5000-
5500' today, lower valley areas will see a few tenths of liquid
today. There is even a 10-15% chance of isolated thunder along the
periphery of the Sierra Crest from the Tahoe basin southward that
extends east into western NV. With the more showery snowfall
confined above those colder elevations, higher mountain locations
will still have at least another 5-15" of accumulated snow with
higher foothill areas gathering another 4"-10" of snowfall
through Sunday morning. Donner pass still has a 50-60% chance of
at least 6" of accumulating snowfall.

* A Twist of Snowy Fate: Wrap around moisture along a deformation
  zone and surface convergence extending from the low pressure
  center lifting east-northwest into west-central NV will bring
  another round of increased snow chances to the Basin and Range
  overnight tonight into Sunday morning. These increased snow
  chances will then extend westward into southern Washoe County,
  eastern Plumas/Lassen counties, the lake Tahoe Basin, and areas
  south to Highway 50 with snow-levels dropping to valley floors
  through the overnight hours where this band sets up. Snow
  accumulations along this snow band can be tricky to access with
  blended guidance showing at least a 20-30% chance for an inch or
  two dropping quickly over area roadways. There is also a 20-30%
  chance for an inch or more of snow making roadway surfaces
  slippery before daybreak Sunday along the US-395 corridor in
  Douglas into Mono Counties, and along US-95 south of Fallon to
  Schurz, and US-95 ALT into the Mason Valley.

Winds: Although some northwest to northerly breezes will kick-up
today with surges of low pressure across the region, winds will
rarely exceed 20 mph for today through Sunday morning.

Sunday Night through Wednesday:

High pressure over the eastern Pacific will now begin to ridge into
the western US through the first half of the upcoming week, bringing
with it drier conditions and light winds across western NV.  But as
the broader area of upper troughing pushes east and southeast Sunday
into Monday morning, winds will shift more easterly across the
region, especially over higher Sierra and western NV ridgetops late
Sunday night through Tuesday morning. Increasingly gusty east-
northeast ridgetop winds will peak at 50-60 mph across the Sierra
crest from the Lake Tahoe Basin south into Mono County. Look for
impacts for those recreating in Sierra backcounty areas as well
as aviation concerns west of the Sierra crest.

Looking Down The Path of the Brier Patch:

Another emerging Spring storm looks to bring another increased
chance for Sierra mountain snow and valley showers. Winds
increasing across the Sierra crest and western NV will play an
initial increased role with this next Spring storm. Parts of
western NV look to have 25-35 mph winds mixing into lower valley
areas Wednesday and Thursday with Sierra ridgetop gusts 70+ mph.
-Amanda

&&

.AVIATION...

* An upper low will continue to bring periods of mountain snow and
  valley rain/snow showers through Sunday. Expect terrain
  obscurement in MVFR/IFR conditions at Sierra terminals with
  predominantly MVFR conditions for lower elevation sites.

* The heavier band of precip currently over far western NV and the
  Sierra will let up some after 15Z. Can't rule out a storm or two
  today (10-20% chance). With snow levels running around 4500 ft,
  some light accumulations are possible for lower valley floor
  airports prior to sunrise (80% chance), especially on exposed
  surfaces (15-20% chance).

* For tonight/Sunday AM, we will be watching a potential heavier
  band of precipitation which could drag snow levels down to valley
  floors of western NV. Confidence is increasing that there will be
  a band, but there still remains some uncertainty in its location.
  These bands are often narrow, but where they set up, more
  appreciable snowfall may occur. It's about a 50/50 proposition on
  it being located anywhere from just north of the I-80 corridor to
  Hwy 50 on the south. Several inches of snow could occur in this
  band while locations outside it will see another rain/snow mix
  with only light accumulations.

Hohmann

&&

.AVALANCHE...

An impactful weather system will continue to affect the region
through Sunday, with heaviest snowfall this morning and again
tonight/Sunday AM.

* Additional liquid totals (SWE) through Sunday: For Mono county
  above 7000 feet, 0.40-0.75". For the Tahoe Basin, generally 0.50-
  1.00" with heaviest amounts along the crest.

* Additional snowfall: 4-10" south of Sonora Pass and 10-16" north
  of Sonora Pass.

* Peak Snowfall Rates: Rates will generally be 1-1.5"/hr but there
  will be both lulls in the snow showers as well as brief heavier
  bursts of 2"/hr in convective showers.

* Snow-Liquid Ratios: Not much change here with 10-14:1 for much of
  the system.

* No significant winds, generally SW-W 15-20 mph, gusts 30-40 mph
  across the highest ridges/peaks.

Hohmann

&&

.REV Watches/Warnings/Advisories...
NV...Winter Weather Advisory until 11 AM PDT Sunday NVZ001-003.

     Winter Storm Warning until 11 AM PDT Sunday NVZ002.

CA...Winter Weather Advisory until 11 AM PDT Sunday CAZ071.

     Winter Storm Warning until 11 AM PDT Sunday CAZ072-073.

&&