330
FXUS65 KREV 051101
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
301 AM PST Wed Feb 5 2025

.SYNOPSIS...

* Gusty to strong winds continue across the region through Friday,
  with breezy winds early Wednesday that will relax Wednesday
  evening.

* A more significant and colder system is expected Thursday into
  Friday with heavy snowfall, strong winds, and colder conditions.

* Lingering Sierra snow showers as the system exits Saturday, dry
  conditions and calm winds return on Sunday.

&&

.DISCUSSION...

Gusty winds will continue to taper through the day today, with
valley gusts 20-25 mph through the afternoon, dropping off to 5-10
mph after sunset. Ridge winds will approach 80 mph as day breaks
this morning, but will begin to relax to 40-45 mph after nightfall.
We will have a short-lived break from the high winds overnight
Wednesday into Thursday morning, before the arrival of the next
impactful system arrives to the region. Temperatures will also
take a slide down today, with average highs of upper 40s for
western Nevada valleys and slightly below average highs in Sierra
valleys near upper 30s to 40 degrees. One thing that will be
rather noticeable will be the return of sunshine as the clouds
exit to the southeast.

Our next impactful system is slated to arrive in the early morning
hours of Thursday, when we will wake to light snow flurries as the
system makes an entrance. A trough dropping in along the
northwestern Pacific coast features a cooler airmass, with some
influence from another system containing warm subtropical moisture
aimed at central California. This will bring varying conditions
throughout the day as the airmasses battle for equilibrium, with snow
levels starting at valley floors early Thursday, then coming up to
6000 ft (north Tahoe Basin) to 7500 ft (Mono County) before
crashing back to valley floors Friday morning. Snow amounts will
be greater along the Sierra crest, where passes such as Donner
could see an additional 2 feet of fresh snow. Sierra front valleys
could see a dusting to half an inch of snow by Friday morning.
Any surfaces that remain wet from earlier rains on Thursday may
freeze over once the changeover settles in. The key thing to focus
in for this storm, is the snow level timing as the system exits
Friday morning. The intrusion of warmer subtropical air will not
be overcome by the colder airmass from the north until Friday
morning as the system is winding down over our region. Due to this
timing and positioning, valley snow accumulations may be limited.

Lingering snow showers will hang around the Sierra for Saturday,
with little to no additional accumulations. Sunday will be our choice
day for cleaning up any wind damaged items or remaining snowfall
from recent events. Taking a look into next week, there is yet
another round of unsettled weather taking shape early week and
lasting through the end of the week. Stay tuned as we train our
eyes toward the week ahead. HRICH

&&

.AVIATION...

* Winds will remain elevated through the early afternoon for area
  terminals. Gusts of up to 25 kts are possible through 21z today.
  Expect periods of turbulence and LLWS to be present through 21z.

* Mountain snow and valley rain showers will trend drier from
  northwest to the southeast as the front exits. By 18z, all
  terminals will be dry. VFR conditions return this afternoon to all
  area terminals.

* Conditions will deteriorate Thursday morning as winds return
  along with snow showers. Valley rain through Thursday afternoon
  will give way to a rain/snow mix late Thursday night into
  Friday morning as the system exits. Sierra terminals will remain
  mostly snow throughout this event. HRICH

&&

.AVALANCHE...

A lull period tomorrow is sandwiched between the exiting winter
weather system and another one arriving Thursday morning. Strong
winds, high elevation snow, and heavy rain are still forecast for
the Lake Tahoe area and southward. Will continue to monitor the late
week system, but it still looks to be fast-moving compared to the
recent system.

* Snow levels: Area snow levels this morning will be to valley
  floors and remain through today. The next (Thursday-Friday)
  system`s snow levels currently look to start around 2500-4500 feet
  in the Northern Sierra Mountains before rising to 6500-7000 feet.
  The East-Central Sierra sees 3500-4000 feet on Thursday before
  rising to 7000-7500 feet Thursday afternoon. Friday morning, snow
  levels tumble once again, with the Northern Sierra falling to 2500-
  3000 feet by Friday evening. The East-Central Sierra will see
  their snow levels range 3500-4500 feet.

* Snowfall totals: Additional snowfall amounts with the next system
  through Friday morning look to be around 12-16 inches for the
  Northern Sierra, with around 2 feet of additional snow expected
  along the highest peaks at Tahoe and southward. As of this
  forecast, the heaviest period of snowfall still are expected to
  take place on this evening and overnight with the Tahoe basin
  seeing 3 to 6 inches of snow in a 6 hour period. Locally higher
  amounts are also in the forecast towards Mono County (up to 8
  inches in a 6 hour period) along the highest peaks. For the late
  week system, the latest forecast came down a little bit as it
  currently calls for around 20-25 inches in the Sierra Crest.

* SWE and SLR: SWE appears to have crept up to between 1 to 2
  inches through tomorrow morning along the Sierra Crest. This
  system is relatively wet, so SLRs will be between 6:1 and 11:1.
  The late week system now looks to bring around 1 to 2 inches of
  SWE with SLRs of 9-16:1 between Thursday and Friday.

-078/HRICH

&&

.HYDROLOGY...

*  A flood warning continues for the Pit River and tributaries in
   northwestern Lassen County. Prolonged moderate to major flooding
   is ongoing near Bieber in Big Valley. Levels are expected to
   increase slowly at the upstream Canby gage into Wednesday before
   a very slow recession. Impacted areas in and around Bieber are
   ~30 miles downstream of the stream gage with numerous tributaries
   in between. As of this morning, levels in Bieber are slightly
   below the February 2017 crest. Levels in and around Bieber are
   expected to remain at very high levels for several days and
   increasing flows from Canby maybe counterbalanced somewhat by
   decreasing flows from lower tributaries.

*  The Susan River at Susanville has risen to a peak of 13.67 feet
   as of Wednesday morning. Since peak flows, the Susan River has
   begun to recede once again. The river is at minor flood stage and
   is expected to continue to fall. The Susan River is not forecast
   to return to flood stage, as rain has ceased to fall over the
   river basin. A flood advisory remains in affect for the Susan
   River and remaining portions of Lassen County.

*  Flooding potential is very low in other areas.

*  Check cnrfc.noaa.gov for updated forecasts.

-Bardsley/HRICH

&&

.REV Watches/Warnings/Advisories...
NV...Winter Storm Watch from Thursday morning through Friday morning
     NVZ002.

CA...Winter Storm Watch from Thursday morning through Friday morning
     CAZ071>073.

     Winter Storm Warning until 6 AM PST early this morning CAZ073.

&&

$$