Wildfire in Nevada, July 27 to 31, 2018

Area Forecast Discussion
National Weather Service Reno NV
214 PM PDT Fri Jul 27 2018

.SYNOPSIS...

Widespread haze and smoke from large fires in California will
continue through at least this weekend and diminish air quality.
Isolated late afternoon thunderstorms are possible in Mono and
Mineral Counties for the next few days, otherwise dry conditions
will prevail. Prolonged heat will affect the region well into next
week with highs above 100 degrees in Western Nevada and above 85
near the Sierra.

&&

.DISCUSSION...

The weather pattern will remain relatively similar for the next
several days as ridge of high pressure persists over the southwest
US. The prevailing message will be continued triple digit heat
in lower elevations (mid 80s-near 90 for Sierra Valleys) through
the middle of next week, with typical late day zephyr-type
breezes. This ridge may finally retreat later next week and allow
a few degrees of cooling as a trough approaches the Pacific
Northwest, but the trade-off would be an increase in wind with
possible gusts of 30-35 mph. This could increase fire weather
concerns due to the prolonged period of hot and dry conditions.

While the heat may produce some health concerns for people who
will be outdoors during the daytime, the dry air mass will allow
overnight lows to dip into the 60s for most urban areas, with 50s
for suburban/rural locations and 40s for Sierra Valleys. Therefore
we are not planning heat advisories. Reno's record high is 102
for Saturday--we may come close or briefly match that level. Then
from Sunday-Wednesday the records are either 103 or 104, probably
just out of reach.

Smoke and haze from the Carr fire will produce reduced air
quality at times across much of western NV-eastern CA especially
from US-50 northward, while the Ferguson and Lions fires will
produce areas of smoke across parts of Mono and Mineral counties.
We'll continue to mention haze through the weekend, with
potential for areas of higher smoke concentrations if these fires
remain highly active. Air quality across the region will be an
issue for sensitive groups and generally unhealthy at times.
There are no indications in large changes in the wind flow
pattern, so these issues will likely persist for some time.

The drier air mass will limit thunderstorm chances across most of
the region into early August. The exception will be later this
afternoon and early evening, where isolated storms are possible in
parts of Mineral, southern Lyon and eastern Mono counties. This
potential decreases further during the weekend with only a few
brief cells possible over far southern portions of Mineral-Mono
counties. On Monday, a weak upper level disturbance may bring a
slight increase in thunderstorm potential across more of Mono
County, with buildups extending farther northward into Alpine
County and far western NV. After Monday, thunderstorm potential
becomes sparse again and retreats to southern Mono-Mineral
counties, with even these areas unlikely to see any storms by next
Thursday-Friday. MJD

&&

.AVIATION...

VFR conditions can be expected with afternoon/evening westerly winds
for today and through the weekend. Gusts around 20 kt are expected
for most area terminals. A stray rain shower/thunderstorm is
possible for KMMH this afternoon with a slight increase in cloud
cover. The chance for thunderstorm development becomes minimal
into the weekend as the center of the ridge shifts slightly
westward, cutting off southern monsoonal moisture flow.

With the dominating high pressure in place, afternoon high
temperatures will be quite hot potentially leading to density
altitude issues, especially for smaller aircraft. With the air
density being lower, aircraft may climb slower than usual during
takeoff.

Smoke and haze will be the main issue for all area terminals going
into the weekend as multiple California wildfires keep burning.
Smoke mainly from the Carr Fire near Redding CA will continue to
infiltrate from the west and settle, enhancing reductions to
slantwise visibility at times and cause mountain obscuration. As
for KMMH, smoke and haze from the ongoing Ferguson Fire will
continue to be a problem causing similar conditions. These
conditions look to stick around for the next few days, depending
on overall wind direction and fire activity. -LaGuardia

&&

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

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