Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 301039

Area Forecast Discussion
National Weather Service Reno NV
339 AM PDT Fri Jul 30 2021


Daily thunderstorm chances are in the forecast through this weekend
with locally heavy rain. Winds will be light except gusty around
thunderstorms. A drier southwest flow will bring decreasing storm
chances and a return to typical afternoon breezes next week. Other
than period of milder weather around storms, temperatures will not
be far from average.



No big changes to the forecast through this weekend as moisture
levels will be anomalously high and combine with daytime heating and
shortwave energy to keep the risk for showers and thunderstorms
going. An upper low off the west coast will slowly eject this
weekend as the ridge shifts slowly westward toward the Desert
Southwest. This will begin to introduce a bit more westerly
component to the flow by Sunday and allow for a gradual decrease in
moisture levels.

For today, moisture will be deepest with main axis through central
NV and a deep southerly flow in the storm bearing layer. There is
abundant cloud cover this morning with a few showers still around
and this may limit storm potential during the morning hours. Storms
may develop late morning along the Sierra, then really get going
during the afternoon as temperatures warm and instability
increases. The pattern for this afternoon looks similar to
previous days where initial storm development is deeper and
capable of heavy rain as they move north and east off the Sierra
into the valleys of northeast CA and western NV. At that point,
CAMs show outflow dominated storms. The flash flood/debris flow
threat will mainly be confined to area burn scars and around steep
terrain where brief intense rainfall rates and QPF 0.25-0.50"
would be problematic.

Debris flows off recent burn scars is our main concern which
includes, the Tamarack, Numbers, Slink, Boot, and Mountain View burn
scars. Heavy rain could also lead to rapid rises on small creeks,
water ponding/flowing over roads, and rock slides in areas of
moderate to steep terrain.

Saturday-Saturday night, a shortwave is progged to lift northward
across the area and may be enough to overcome the extensive cloud
cover to produce another round of storms and locally heavy downpours
by the afternoon/evening with storms continuing into Saturday
night. This would keep the threat for flash floods going for area
burn scars. By Sunday, the wave lifts out and drier westerly flow
begins to push things off the Sierra. So we may see a decrease in
the overall coverage Sunday.

The Dixie Fire remains the main contributor to reduced air quality
into the weekend. Southerly flow the next couple days should keep
new smoke from pushing into Reno-Tahoe and points south. Heavy rain
and some gusty outflow winds from thunderstorms could improve air
quality for any lingering haze/smoke trapped in valleys. Hohmann


Southwest flow returns to the region next week which will push
monsoonal moisture east, bringing drier air and warmer temperatures
back to the region. A weak shortwave moving into Oregon early in the
week could allow for isolated thunderstorms to continue in
western Nevada on Monday, but a break in thunderstorm activity is
expected for the remainder of the week.

Temperatures will warm back into the mid 90s or so in the lower
elevations and back into low to mid 80s in the Sierra with a return
to typical afternoon zephyr breezes. -Zach



Widespread thunderstorms are expected in the Sierra and western
Nevada today, developing from south to north, and starting as
early as 18z. Main threats will be heavy rain, erratic wind gusts
40+ knots, and reduced CIG/VIS with mountain obscuration.
By Saturday widespread cloud cover is expected with continued
thunderstorm development in the afternoon.

Smoke continues to impact areas around the Dixie Fire near Quincy
and Susanville with only minor impacts to visibility currently
expected to terminals in Reno/Tahoe. -Zach


.REV Watches/Warnings/Advisories...
NV...Flash Flood Watch from noon PDT today through this evening

CA...Flash Flood Watch from noon PDT today through this evening



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