929
FXUS65 KREV 262359
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
359 PM PST Tue Nov 26 2024

.UPDATE...

Snowfall accumulations are projected to decrease below criteria with
only light snow showers continuing through the remainder of this
afternoon into the evening. Therefore, the Winter Storm Warning for
Mono County has been cancelled. Travelers should continue to use
caution going through this area as slick and snowpacked roads will
cause hazardous driving conditions. -078

&&

.PREVIOUS DISCUSSION... /issued 127 PM PST Tue Nov 26 2024/

.SYNOPSIS...

* Mountain snow and valley rain showers continue through today
  before tapering off tonight. Snow will be wet and heavy with the
  most significant accumulations above 7000 feet in the Sierra.

* Gusty southwest winds may impact valleys and lead to choppy lakes
  and bumpy airplane rides today.

* High pressure returns for the Thanksgiving weekend bringing drier
  and cooler conditions.

.DISCUSSION...

As an upper air trough moves across the NW CONUS, mountain snow and
valley shower chances look to continue today with the latest
radar imagery showing showers in areas north of US-50 as well as
some snow in southwestern Mono County near pass level in the
Sierra Mountains (though better reflectivity looks to be on the
other side of the mountains). When looking at the 12Z run of the
HREF, these precipitation chances look to depart from most of the
region by 6-7 PM PST with some lingering showers in southern Mono
county that look to end around 9-10 PM PST. Additional snowfall
totals in locations north of US-50 that see snow look to be up to
around 1 to 2 inches with portions of Lassen county possibly
seeing up to 3 inches by tonight. Higher elevations of Mono county
in the Sierra may see an additional 5 to 7 inches by tonight with
the mountain summit portions south and west of Mammoth Lakes
seeing additional snow totals pushing the double digits. As such,
the Winter Storm Warning continues through 4 PM for the Greater
Tahoe Area and through 10 PM for Mono County. Travelers across the
Sierra Mountains may want to consider delaying their trips until
tomorrow if can as the latest WSSI (Winter Storm Severity Index)
shows minor to moderate impacts for today. For more winter weather
information including the Winter Storm Warning, please visit
www.weather.gov/rev/winter. While the gusty west-southwesterly
winds continue in the Sierra this afternoon, the forecast calls
for diminishing winds overnight with some of the Sierra mountain
summits in Mono County seeing wind gusts up to around 50 mph
continue for a few hours past midnight.

For tomorrow: dry conditions, lighter winds, and cooler
temperatures are in the forecast as the CWA sees a northwesterly
flow aloft with the trough having departed to the east. Daytime
high temperatures look to be in the middle 30s to lower 40s range
in the valley areas with the Sierra Mountain communities seeing
highs in the 20s to lower 30s range. Overnight lows dip down into
the single digits to the lower teens range in higher elevations
tomorrow night with valley communities seeing lows in the middle
teens to lower 20s range.

On Thanksgiving and going through the holiday weekend, forecast
guidance calls for a Pacific upper air ridge to progress eastward
over the CWA which points to signs of a warming trend as well as
relatively low chances for more precipitation at this time. With
this in the forecast, some valley portions of the CWA could
potentially see daytime highs return to the lower 50s over the
weekend and into early next week. Will be monitoring for air
stagnation potential with this ridge moving in as well with area
forecast soundings showing possible atmospheric inversions
returning later this week. -078

.AVIATION...

VFR and MVFR conditions conditions for KRNO/KCXP/KMEV. However, may
get down to IFR conditions for Sierra sites today due to snow
showers. Conditions will improve after 27/02Z for KTRK, 27/04Z for
KTVL, and 27/07Z for KMMH.

Periods of LLWS for KMMH from 27/00Z until 27/07Z. Otherwise, expect
westerly winds with gusts up to 25 kts across the area. After
sunset, winds drop to light and variable.

Turbulence expected over the entire Sierra and into the western NV
valleys until 27/04Z. -Giralte

.AVALANCHE...

Wintry precipitation and gusty winds continue through the rest of
the day before both the precipitation chances and enhanced winds
diminish overnight. The Winter Storm Warning continues through 4
PM for the Greater Tahoe Area and through 10 PM for Mono County.
Beyond this winter event, dry conditions are in the forecast
beginning tomorrow and going through the holiday weekend with a
Pacific ridge moving over the area.

Snow levels: Slowly drop through the rest of the day to below 5 kft
this evening and going into the night.

Snowfall rates: While most of the Sierra Passes see rates less than
one inch through the remainder of the event, rates of around 1.0-1.5
inches look to continue for Mammoth Mountain and Tioga Pass through
around 3 PM PST before rates drop to less than an inch going into
the night.

SWE: North of Ebbetts Pass: An additional tenth of an inch or less.
Ebbetts Pass to Tioga Pass: 0.30-0.60 inches. Then South of Tioga
Pass amounts look to be around an additional 0.80-1.00 inches.

Winds: Southwest ridge winds of around 60-80 mph continue this
afternoon before diminishing going into the evening. Midslope gusts
of 40-60 mph continue this afternoon that diminish this evening as
well. -078

&&

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

$$