Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 041031

Area Forecast Discussion
National Weather Service Reno NV
331 AM PDT Thu Jun 4 2020


Temperatures remain well above average through Friday before a
substantial cool down occurs this weekend into next week. A few
thunderstorms remain possible today in the eastern Sierra with
more widespread chances south of I-80 Friday. Strong gusty winds
Saturday with chances for rain and snow showers along the cold
front Saturday and Sunday. Freezing temperatures are possible
Sunday night.



A couple more warm days to finish off the week before another
dramatic shift to colder weather returns for the weekend. Daytime
high temperatures 10-15 degrees above average continue today as
high pressure persists over the region. A cutoff area of low
pressure off the Baja coast is forecast to slowly move inland as
it is absorbed into a larger area of low pressure moving into the
western U.S. this weekend.

Winds will be breezy again today and Friday as strong surface
gradients create our daily zephyr breeze. Upper level winds begin
to pick up Friday as the cold front approaches. The strongest
winds are expected on Saturday as the cold front approaches the
region with widespread gusts of 35-45 mph.

A few thunderstorms remain possible today along the higher
terrain of the eastern Sierra and the Sweetwaters, but development
is expected to be limited in intensity and coverage. Better
chances for thunderstorms exist on Friday as the cutoff low
pressure approaches, bringing some additional instability and
forcing. The best chances will again be centered in Mono and
Mineral counties with more isolated storms extending north to
around I-80. A mix of faster moving drier storms and a few wetter
storms are possible Saturday with stronger storms possible as
shear increases. For more on the fire weather aspect see the Fire
Weather section below.

Much cooler temperatures are expected by Saturday as the cold
front begins to move through the region. Rain and even some snow
showers are expected along the front Saturday, mainly confined to
the Sierra and northeast California. Snow levels could drop as
low as 5000-6000 feet Saturday night, but accumulations are
expected to be light with accumulations limited to higher
elevations due to the warm ground temperatures. -Zach

.LONG TERM...Next Week...

The upper low will be moving across the area on Sunday with
sufficient instability to produce extensive cloud cover and
scattered showers (some pellet showers possible most areas as snow
levels will be around 5000 feet to start the day). Some brief light
snow accumulations are possible for Sierra passes around the Tahoe
Basin northward to Fredonyer Summit and Cedar Pass in northeast CA.
Any accumulation will quickly melt after 9 am given the time of
year, thus any road impacts would be early Sunday morning. It will
be unseasonably cool with all the clouds and brisk northwest winds.
Highs will struggle to reach 50 degrees in the Sierra valleys and
lower 60s for many lower elevations. If you have plans in the Sierra
backcountry, be prepared for unusually cold temperatures (highs in
the mid 20s to mid 30s).

The trough is forecast to shift east Sunday night and Monday with
showers ending, skies clearing and winds decreasing. Sunday night is
going to be the coldest night of the period with freezes/light
frosts continuing to look likely for all colder valleys (20-25
degrees in Sierra valleys and 27-32 degrees for colder lower
elevation valleys). Preparations should be made to protect plants
from the very cold temperatures Saturday night through Monday

A shortwave ridge will bring warmer and dry conditions Tuesday and
Wednesday with light winds. Ensemble clusters continue to show
another trough for late next week into the following weekend for
another round of gusty winds and cooler temperatures. Spring is not
letting up easily. Hohmann



Gusty afternoon and evening zephyr winds will continue through
Friday with strongest gusts 25-30 kts from the Sierra Front
northward along Highway 395 and into northwest NV. Thunderstorms
will remain isolated and confined mainly to the eastern Sierra in
Mono County (10-15% chance at KMMH). On Friday, thunderstorm
coverage will increase across Mono-Mineral Counties with isolated
storms possible as far north as I-80, mainly along and east of
Highway 95. Gusty outflow winds to 40-50 mph will be the primary
impacts with stronger storms.

A strong late season trough will bring a substantial increase in
winds Saturday with widespread turbulence and periods of
LLWS/rotors. Surface gusts 35-40 kts with ridge wind gusts to 70+
kts. Blowing dust may reduce visibility below one mile at times in
western NV Saturday afternoon/early evening. Hohmann



A trough over the Pacific Northwest has dipped far enough south to
bring increasing ridge level winds to the Tahoe Basin/Sierra Front
northward to the Oregon border. Gusts were currently around 40-45
mph on some of the higher peaks. Latest model data indicates these
winds will likely continue through Friday as the trough remains
nearly stationary. Heating in the Basin and Range will bring
tightening thermal gradients each afternoon and combined with mixing
of winds aloft, gusty surface winds are expected to develop in these
areas each day with strongest winds across fire zones northern 420-
458-eastern 278. Several hours of near critical fire weather
conditions from gusty winds and humidity levels 10-15% are possible
between 2pm and 8 pm. Any fire starts will be capable of fast
spreads where fuels are ready.

Thunderstorms will remain very isolated across fire zones 421-274
this afternoon. Thunderstorm coverage increases Friday, with
isolated storms pushing north along and east of Highway 95 and as
far north as I-80. Storms will be more numerous and wetter for fire
zones 421-274 with storms farther north a bit drier. Strong outflow
winds to 40-50 mph will be the biggest threat for any fire starts.


.REV Watches/Warnings/Advisories...


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