085
FXUS65 KREV 202000
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
100 PM PDT Thu Aug 20 2026

.KEY MESSAGES...

* Dry and warm conditions today across the region, with a downward
  trend in temperatures starting Friday.

* Increasing gusts on Friday and Saturday lead to elevated to near
  critical fire conditions for northeast CA and northwest NV.

* Isolated shower and thunderstorm potential returns for the NV
  Basin and Range, and south of US-50 Friday into the weekend.

&&

.DISCUSSION...

One last day of warm temperatures to get through before we see
cooler daytime highs roll into town. The inbound trough will help to
modify the airmass toward a more seasonally average temperature
regime. While we will still hover above August averages, we will say
goodbye to the near 100 degree valleys and 90s across the Sierra
valleys.

The trough will also be responsible for increasing winds, beginning
Friday when afternoon gusts will approach 30 mph. Then for Saturday,
gusts of 35-40 mph will be felt by northeastern California and
northwestern Nevada as the trough and associated tighter gradient
draws nearer. When coupled with the low relative humidity readings
anticipated for Friday and Saturday, we expect elevated to isolated
areas of critical fire weather conditions both days, with emphasis
on Saturday prompting a Fire Weather Watch. See details on this
product below in the Fire Weather portion of this discussion.

The other feature that will become part of our weather story this
weekend is the persistent ridge over the Four Corners that will
allow for a southerly flow to draw monsoonal moisture back into the
southern Sierra and southern Basin and Range areas. PWAT values will
range 0.6-0.8 inches, which usually spells showers and storms for
the area. The limiting factor for convection may be the limited CAPE
values of 100-500 J/kg, the higher end being more favorable. This
should translate to isolated shower and storm behavior, although
some recent CAMs are highlighting a potential for showers to develop
over Mineral/Churchill/Pershing counties, then progressively move to
the northeast with potential for developing outflows that may reach
speeds to 40 mph. Another feature became noticeable today that looks
to be some remnants of a tropical wave that is gliding westward
along the Mexico border. Will this feature be drawn into the
southern extent of our County Warning Area? We are watching... HRICH

&&

.AVIATION...

* High based clouds across the region signal the arrival of an
  inbound trough that will linger into the weekend. Today will see
  gusts of 20 kts at area terminals between 21z-04z, with VFR
  conditions. Friday, gusts increase over the same time frame to
  around 30 kts, then on Saturday another increase up to 35 kts.

* Showers and storms may impact KMMH/KHTH/KBAN Friday and
  Saturday. Chances on Friday of up to 5%, increasing to 10-20%
  for Saturday. HRICH

&&

.FIRE WEATHER...

* Elevated fire risk for Friday with an increase of west to
  southwesterly winds to around 30 mph and min RH around 12-20% for
  portions of eastern Lassen, the Surprise Valley and northern
  Washoe counties. Conditions deteriorate to critical by Saturday
  over the same area with gusts to 30-35 mph with a 10-50% chance of
  exceeding 40 mph on Saturday, and similar min RH compared to
  Friday. Critical conditions are expected to last for 3-6 hours
  between Saturday afternoon and early evening. For these reasons,
  we are adding headlines to our fire weather products for Friday
  and have issued a Fire Weather Watch from 11 AM through 11 PM
  Saturday for northern Washoe and eastern Lassen counties, and
  Surprise Valley in Modoc County.

-HC/HRICH

&&

.REV Watches/Warnings/Advisories...
NV...Fire Weather Watch from Saturday morning through Saturday
     evening NVZ458.

CA...Fire Weather Watch from Saturday morning through Saturday
     evening CAZ270-278.

&&

$$