355
FXUS65 KREV 201018
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
318 AM PDT Wed Aug 20 2025

KEY MESSAGES...

* Warm and dry conditions remain through Thursday.

* Hot temperatures bring a risk for widespread heat impacts from
  Friday into Saturday.

* Monsoonal moisture brings back showers and thunderstorms to the
  forecast Friday through next week.

DISCUSSION...

Dry air and clear skies continue to dominate the weather pattern
this morning and through tomorrow. The expansion of the upper
level ridge from the Four Corners into the Great Basin will
support this development. Subsequently, afternoon temperatures
will continue to rise each day reaching peak heating by Friday
afternoon. On Friday, max temperatures will be in the upper 90s
to 103F in western NV and NE CA valleys, and 80s to low 90s in
Sierra communities. Reno has a 65% chance of exceeding the
century mark, while Susanville has a 75% chance, and lower valleys
in the NV Basin and Range have an 80-95% chance on Friday
afternoon. Saturday morning lows appear to remain quite warm in
the upper 60s to lower 70s, most likely a result of convective
debris from possible storms in the previous evening keeping the
heat in. Anyway, the ensuing heat will result in heat advisories
for most western NV valley locations and portions of eastern
Lassen county Friday into Saturday morning.

As the upper ridge expands it also shifts the moisture plume
currently affecting portions of New Mexico and west Texas. The
diversion to the west will lead to a quick increase of moisture
over NV and CA by Friday. Thursday may already start seeing some
slight chances for showers and thunderstorms, less than 10% over
Mono and Mineral county. Nevertheless, by Friday those chances
increase to 20-50% in the same area, and expand to the north
towards the Tahoe Basin and the Sierra Front with a 10-20%
probability of storms. Friday also has the highest threat for dry
lightning that could lead to new fire starts.

This weekend, the coverage of showers and thunderstorms becomes
widespread across the entire CWA, especially by Sunday. The main
area of concern will remain in the southern and eastern parts of
the region. However, any storm will be capable of producing
periods of moderate to heavy rain, gusty outflow winds, frequent
lightning and small hail. The risk for dry lightning decreases
with more moisture in store across the area. Areas from the Tahoe
Basin/Sierra Front towards southern Churchill have a 40-50% chance
for showers and thunderstorms, south of those areas the chances
increase to 60-75%.

Next week, showers and thunderstorms hang around the area, but
temperatures drop as the moisture remains leading to more cloud
cover plus the approach of an upper trough from the northwest
possibly bringing colder air.

-HC

AVIATION...

VFR conditions expected to continue over the next 24 hrs. The main
hazard continues to be gusty afternoon winds with gusts to 10-20 kts
between 20-3Z. Heat continues to rise each day leading to density
altitude concerns for western NV terminals. Afternoon storms
return to the forecast Friday afternoon.

-HC

FIRE WEATHER...

Dry conditions persists over the next few days, but with lighter
winds. Still some localized areas in the lee side of mountains may
observe elevated conditions in the late afternoon and early
evening hours.

As the upper level ridge settles in the region, monsoonal moisture
below brings back chances for showers and thunderstorms. Friday is
the day which dry lightning is most likely as the moisture slowly
slips in. The combination of gusty outflow winds and dry lightning
may spread new fires quickly. Afterwards, the influx of moisture
and the potential for moderate to heavy rain should limit the
likelihood of dry lightning to the periphery of rain cores on
Saturday and beyond.

-HC

&&

.REV Watches/Warnings/Advisories...
NV...Heat Advisory from noon Friday to 9 AM PDT Saturday NVZ001-
     003>005.

CA...Heat Advisory from noon Friday to 9 AM PDT Saturday CAZ071.

&&

$$