Area Forecast Discussion
Issued by NWS Reno, NV

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769
FXUS65 KREV 182004
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
104 PM PDT Fri Jul 18 2025

.KEY MESSAGES...

* Isolated showers and thunderstorms possible today and tomorrow
  afternoon south of US-50, especially in Mono and Mineral
  counties.

* Seasonably hot and dry into the weekend with typical afternoon
  breezes. Hazy skies along the Oregon border from wildfire smoke.

* Stronger winds are trending more likely early next week, which may
  impact travel and recreation, and elevate fire concerns.

&&

.DISCUSSION...

The weather button is stuck on loop for today and Saturday with
routine afternoon thunderstorms for Mono and Mineral counties,
typical summertime temperatures and afternoon breezes.

Westerly flow continues transport smoke and haze from the fires in
California into portions of the areas. The active Green and Butler
wildfires continue to burn resulting in detrimental air quality for
portions of Lassen county, northern Washoe County and Surprise
Valley. Elsewhere in the Sierra and western Nevada, we have seen
bouts of moderate air quality, but for the most part hazy skies have
been the impact.

We`re looking another couple of days of a 15-20% chance of
thunderstorms over Mono and Mineral counties. There is also a
small chance (15%) of storms popping up for far northern Washoe
county. Heating and sufficient moisture will continue to promote
pop up thunderstorms. Main impacts from storm today will be gusty
outflow winds, especially with DCAPEs riding around 1000-1300 J/kg
by the afternoon. Areas south of Highway 50 have the best shot at
storms today, especially with precipitable water values 0.3" and
below in the Interstate 80 vicinity. The 0.4-0.5" line runs from
Mono Lake across to Walker Lake as of midday today.

By Sunday into Monday, a significantly drier air mass pushes into
the Sierra and western Nevada as west to southwest flow increases
across the region with a trough`s arrival. For context, precipitable
water values are running around 0.3-0.5", but the forecast sounding
for Reno is showing values dropping to near 0.1" by Sunday
afternoon. The much drier conditions combined with the increase in
the winds raise concerns for critical fire conditions. See the Fire
Weather section for more. Temperatures will cool with the trough`s
entrance, but the winds will ramp up to be stronger than our typical
day-to-day winds. Widespread wind gusts will be in the 30 to 40
mph range, with even stronger winds in the wind prone areas and
the Sierra.

-Edan

&&

.AVIATION...

Seasonably hot temperatures with widespread VFR conditions and
typical afternoon breezes. Main exception is for KMMH where there is
a 15-20% chance for thunderstorms between 20Z-04Z this afternoon.

Afternoon westerly winds with gusts up to 25 kt are expected today
and tomorrow across all terminals. Lingering heat will maintain
density altitude concerns for western Nevada terminals.

A stronger bout of winds is projected to arrive late Sunday into
Tuesday, where afternoon westerly wind gusts may exceed 30kts.

-Edan

&&

.FIRE WEATHER...

Transient low pressure will encourage winds to become a bit stronger
than typical afternoon zephyr breezes Sunday and Monday afternoons
as it traverses the Pacific Northwest. Winds appear to be marginal
on Sunday with SW/W gusts around 30 mph, but likely surpass critical
thresholds Monday afternoon as gusts increase to 35-40 mph. RH
reductions to 7-15% are expected each day from the Sierra Front
into the W NV Basin and Range.

A brief, 1-3 hour period of locally critical fire weather conditions
is probable Sunday afternoon from eastern Lassen County into the
northern Sierra Front. Duration of critical conditions extends to 2-
4 hours Monday afternoon and expands eastward into the W NV Basin
and Range. Overnight recoveries will be poor across western Nevada
each night through Monday AM as RH struggles to exceed 35%, but
improves Monday night.

Winds weaken after Monday with more typical afternoon breezes next
week, although thunderstorm chances increase around the middle of
next week.

-Salas

&&

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

$$