181
FXUS65 KREV 030944
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
244 AM PDT Fri May 3 2024

.SYNOPSIS...

Warmer temperatures continue today, with light winds. Active
weather returns with a storm system bringing gusty winds along
with valley rain and mountain snow, with conditions slowly
improving Sunday. Early next week, a slow warming trend with low
chances for precipitation remain in the forecast.

&&

.DISCUSSION...

Enjoy the calm, warm weather today because it`s all coming to a
quick end by the weekend. High-resolution models and the HREF are
picking up some isolated showers is in Alpine, Mono, and into
Mineral counties, where there is a slight 10-15% chance of
precipitation during the early afternoon. Otherwise, we`ll see
mostly seasonal temperatures today with low to mid-60s for Sierra
communities and northeast CA while upper 60s to low 70s are
expected in western NV.

WEEKEND STORM:
It seems like our spring weather pattern enjoys messing up our
weekend plans by always returning us to winter! Near-term models
all show an anomalously cold, dynamic low pressure system moving
into northern CA by Saturday afternoon with a strong cold front
moving through the area. This low then transits east into the
central Great Basin by Sunday afternoon. As a reference, ensembles
show 500mb temperatures of -28 to -30C, which falls into the
lowest 1/10th percentile for the date and what we usually expect
in January! Let`s dive into the details of your ruined weekend
below:

* Winds: As this system moves into the region, strong southwest
  winds will begin to increase by late Friday night through
  Saturday. Ensembles show an increasing 700mb jet upwards of
  40-50kts dropping south, with the strongest gusts prior to
  frontal passage on Saturday afternoon. At this moment, gusts
  upwards of 80-100 mph are conceivable along the ridges
  throughout the eastern Sierra. Additionally, US-395 in Mono
  counties may see wind gusts upwards of 50-60 mph with stronger
  gusts to 70 mph in wind prone areas. Strong winds will also
  materialize for the rest of western NV on Saturday, where gusts
  of 45-55 mph are possible with stronger gusts upwards of 60-70
  mph in wind prone areas such as US-395 from Reno to the CA/NV
  border and US-95 in Mineral County near Hawthorne. There is a
  40-60% probability for damaging winds from south of I-80 into
  Douglas, Lyon, Mineral and Mono counties.

* Snow/Rain: Not a significant change to the latest QPF guidance.
  When it`s all said and done, western Lassen southward through
  Alpine County, as well as along the crests in Mono County have a
  likely 60-80% chance for at least 0.50". The highest crests in
  the Tahoe Basin have a 40-60% chance for at least 1.00", with
  only a 20-30% of 1.00" in Mono County. Snowfall totals as well
  as snow probabilities have increased compared to prior guidance.
  There is a likely >80% chance for at least 2" of snow at lake
  level in the Tahoe Basin, with a likely (>70%) chance for at
  least 6" of snow along the Sierra crests from Mono County
  northward into western Lassen County. There is even a 40-60%
  chance for isolated amounts up to 12" along mountain passes
  (US-50). Lastly, Snow levels will start at around 6,000-7,000
  feet in the Tahoe Basin northward, to around 8,000-9,000 feet in
  Mono County before falling to around 5,000 feet everywhere by
  Saturday evening. We might see some snow flurries into western
  NV Saturday night.

* Temperatures: It will be downright cold for May standards on
  Saturday and Sunday. High temperatures will be upwards of 15-20
  degrees below average, as we struggle to hit 40 degrees for
  Sierra communities and low 50s in western NV. There is
  additionally the chance for sub-freezing temperatures in western
  NV and northeast CA on Sunday and Monday mornings.

* By Monday into next week, ensembles begin to diverge in
  solutions in either a long-wave trough pattern across the west,
  or a ridge building in from the eastern Pacific. At this time,
  we keep below average temperatures Monday into Wednesday as we
  warm back up from the weekend storm with near average by the
  end of next week. We`ll hang on to low chances for additional
  showers on Monday, with drier conditions the remainder of the
  week.
- Mckellar

&&

.AVIATION...

* Friday will feature pleasant flying conditions with light winds
  and clear skies though around 03z. There is a slight (10-15%)
  chance for showers for KMMH Friday afternoon.

Weekend Storm: A strong, cold spring storm system is moving into
the region Friday night into Saturday.

* Snow/Rain: Widespread mountain snow showers and valley rains are
  likely (>70%) late Friday night into Saturday evening throughout
  the eastern Sierra, northeast CA, and western NV. This is a
  colder airmass allowing snow levels to drop to 5000-5500 feet by
  Saturday night. Sierra terminals KTRK, KTVL, and KMMH could see
  between 2-4" of snowfall with a 80% chance for at least 2".
  However, high sun angle in May may limit accumulations during
  the day. There is also a slight chance for snow flurries
  Saturday night into Sunday morning in western NV.

* Winds: Strong west to southwest winds will ramp up across the
  Sierra as early as Friday night and will continue through
  Saturday night. Sustained ridgetop winds in the Sierra of
  30-50kts with gusts upwards of 60-80kts are are conceivable
  during this time period. Expect periods of mountain wave
  turbulence, as well as LLWS for all area terminals. Otherwise,
  strong west to southwest winds are possible for all western NV
  and Sierra terminal on Saturday.
-McKellar

&&

.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 8 AM to 5 PM PDT Saturday NVZ005.

     Winter Weather Advisory from 11 AM Saturday to 8 AM PDT Sunday
     NVZ002.

     High Wind Warning from 8 AM to 8 PM PDT Saturday NVZ001-003.

     Lake Wind Advisory from 8 AM to 8 PM PDT Saturday NVZ004.

CA...Wind Advisory from 8 AM to 5 PM PDT Saturday CAZ070.

     Winter Weather Advisory from 11 AM Saturday to 8 AM PDT Sunday
     CAZ071>073.

&&

$$