000
FXUS65 KREV 042042
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
142 PM PDT Tue Aug 4 2020

.SYNOPSIS...
Afternoon temperatures will be a bit cooler Wednesday and Thursday
followed by a slow warming trend going into the weekend. Late
afternoon and early evening thunderstorms may return as early as
Wednesday and could persist through the weekend and into early
next week.

&&

.DISCUSSION...
Much less haze about Sierra and western Nevada today as fire
activity has diminished a bit. However pockets of smoke and haze
from the Stump Fire may impact Lassen County. The flow aloft
starts to turn toward the south for Wednesday, which could allow
haze to drift northward into Mono and Mineral Counties from the
Stagecoach and Apple Fires in southern California.

No big changes in the ensemble guidance with trough set to move
into northern California tomorrow. This will set the stage for
increased instability and thunderstorms over the Surprise Valley
and the northern portions of Lassen and Washoe Counties. Models
were also showing an outside chance of a late afternoon
thunderstorms for northern Mono County, moisture may be a bit
lacking for any significant thunderstorm development.

Once this trough moves into northern California the flow aloft
becomes rather weak which will allow the trough to drift around
northern CA or just off the CA coast for several days. This will
lead to a persistent chance of thunderstorms along the Sierra
Crest, far western NV and into northeast California for Thursday
and into early next week. With warming temperatures over the
weekend and slowly building moisture, thunderstorms could turn
strong and produce hail, heavy rain, and outflow winds over 40
mph this weekend. Lightning will be an issue as well, especially
for outdoor recreation. Have a Plan B and quick access to shelter
if you have outdoor plans in the afternoon and evening hours this
weekend. Brong.

&&

.AVIATION...
Zephyr breezes into this evening with peak gusts near 25 kts. Some
haze and smoke from the Stump Fire may drift into Lassen County
with some minor visibility reductions. Some haze from southern
California wildfire may drift northward into Mono/Mineral Counties
late Wednesday.

Thunderstorms should return tomorrow with a 15-25% chance after
21z for areas north of Susanville CA to Black Rock Desert NV. Low
pressure settles over California Thursday with increasing chances
of showers and thunderstorms for the Sierra and western NV at
least into the weekend. Brong

&&

.FIRE WEATHER...

Winds...Zephyr breezes to 30 mph today and tomorrow will decrease
for Friday and the weekend. Afternoon humidity should rise a bit
with the cooler temperatures, but overnight recoveries will remain
rather low on mid and upper slopes.

Thunderstorms...Low pressure moving into California tomorrow will
bring a 15-25% chance of storms to the Surprise Valley and
northern portions of Lassen and Washoe Counties. Not much moisture
will be available for rainfall, so expect some dry lightning
strikes and gusty outflow winds. There is also a 10-15% chance of
a late afternoon thunderstorm over northern Mono County, and the
southern portions of Lyon and Douglas Counties.

Thunderstorms will continue to be a threat to the region from
Thursday through the weekend as low pressure hangs around the
California. Increasing moisture and very little storm movement
should allow most storms to produce some wetting rains, but
lightning on dry mid summer fuels is a threat for new fire starts.
Brong

&&

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

$$

For more information from the National Weather Service visit...
http://weather.gov/reno