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000
FXUS65 KREV 252107
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
207 PM PDT Mon Sep 25 2023

.SYNOPSIS...

Smoke from the Quarry fire will impact air quality this evening
south of US-50. An approaching trough continues to bring gusty winds
in the Sierra, northeast CA, and western NV into the evening.
Impacts to lake recreation, aviation, and travel are possible.
Critical fire weather conditions will continue across northeast CA
and northwest NV into the early evening.

&&

.DISCUSSION...

Looking out the window today, there is little in the way of any
visibility reductions in haze and smoke from the Quarry fire near
Strawberry in Tuolumne County, CA, since there is little in the
way of smoke and haze right now in the area. That may not be the
case in a few more hours after the wind dies down later this
evening. It would be a good idea to check the AQI at AirNow.gov
(https://tinyurl.com/4u7y5cjx) before taking any subsequent deep
breaths outside just in case.

GUSTY WINDS: Since winds were already mentioned earlier, I’ll
continue by saying that the gusty west to southwest winds will
continue into this evening. These conditions will persist until a
cold front swings across northern CA, southern OR and northwest NV
later this afternoon and overnight as well. Until then winds will
gust 30-40 mph with some wind prone areas across the US-395
corridor in northeast CA seeing a few gusts to 45 mph before
dissipating overnight after passage of the front. Winds across
higher Sierra ridges will continue to gust 60+ mph into the
evening before gradually dissipating to less than 40 mph later
Tuesday AM. Winds overnight will gradually decouple overnight
into Tuesday with southwest winds returning in the afternoon but
gusting only to 20-25 mph before decreasing <10 mph later in the
evening.

DRY WITH FIRE CONCERNS: Very dry conditions accompanied the gusty
winds across the region this afternoon, especially across
northwest NV where observed RH’s range from the low teens to low
20s which correlates well with a dry slot transiting east over
western NV. The combination of gusty winds and low RH today
continue to produce elevated to locally critical fire weather
conditions between for most areas north of I-80. As a result, a
Red Flag Warning remains in effect for the Surprise Valley,
eastern Lassen County, and northern Washoe County until 8PM.
Please exercise extra caution when recreating outdoors, especially
with any activities that may cause a spark! A deeper dive into
regional fire weather conditions is included below in the Fire
Weather section.

PRECIPITATION TONIGHT: Although much of the Sierra and western NV
will be spared of any measurable rainfall, parts of northeast CA
east of US 395 will see some precipitation overnight tonight into
Tuesday morning. The weakening trailing branch of a moderate AR
will overnight spread light showers across northeast CA before all
but drying out Tuesday morning upon reaching the western
outskirts of northern Washoe County. Blended guidance and Hi-Res
CAMs are holding out for a few hundredths of an inch (30-50%
chance) in lower elevation areas to at least a quarter inch
(15-25% chance) of precipitation across higher terrain of western
Lassen and eastern Plumas counties.

THE LOOK AHEAD: Drier conditions, lighter winds, and near
seasonal temperatures will continue through Friday across much of
the Sierra and western NV. Winds may stay breezy through Tuesday,
though not as strong as today. Another shortwave will pass by
Wednesday but may only enhance afternoon breezes along the
CA/OR/NV border areas as well as increase mid and high level
clouds across western NV. Ensemble mean and cluster guidance paint
a different picture Friday through this upcoming weekend. There
is general agreement across model guidance that another low
pressure system will drop into the region and usher in a colder
and wetter pattern to the region. It is still a bit to far out to
make any confident temperature and precipitation projections at
this point, but forewarned is forearmed! -Amanda

&&

.AVIATION...

* VFR conditions will persist for main terminals through the
  forecast period. FL100 winds look to continue from the southwest
  around 30-40 kts until 18Z Tuesday before gradually decreasing to
  20-20kts later Tuesday afternoon. Therefore expect continued
  enhanced ridge-top winds, periods of LLWS, and mountain wave
  turbulence over the Sierra (KSVE/KTRK/KTVL) and far western
  terminals(KRNO/KCXP/KMEV) overnight into Tuesday morning.

* Terminals west of US-395 in Lassen County (KSVE) have a 15-20%
  chance for a few hundredths of an inch of rainfall and brief
  periods of MVFR ceilings from 06-15Z Tuesday.

* Periods of smoke and haze, due to the Quarry fire near Strawberry
  CA, could bring lowered slantwise visibility overnight into the
  Tuesday morning. Terminals south of US-50 and west of US-95 could
  see brief periods of MVFR conditions from smoke this evening as
  high-res model guidance projects denser portions of the smoke
  plume dropping into that area between 00-09Z. -Amanda

&&

.FIRE WEATHER...

* Elevated fire weather concerns continue into early evening as a
  combination of gusty winds and low humidity will prevail across NE
  California and NW Nevada today. Current observations across
  portions of the Surprise Valley, N.Lassen, and far N.Washoe
  counties have observed gusts in the 30-45 mph range as of about
  noon. Minimum RH has also dipped into the single digits across the
  W.NV Basin and Range with mid-teens across N.Washoe and E.Lassen
  counties. Overall, expect a period of 3-7 hours of critical fire
  weather conditions through early evening across these areas.

* Rainfall with this system will be limited to far western portions
  of Lassen County and the western half of Plumas County mainly by
  around midnight tonight into early Tuesday morning. While there
  will be a 25-50% chance of showers across these areas, wetting
  rain potential (at least 0.10") will be limited to a 15-30%
  chance. Elsewhere across western Nevada and the eastern Sierra,
  chances for isolated showers will be less than 5%. Fuentes

&&

.REV Watches/Warnings/Advisories...
NV...Red Flag Warning until 8 PM PDT this evening NVZ458.

     Lake Wind Advisory until 8 PM PDT this evening for Pyramid Lake
     in NVZ004.

CA...Red Flag Warning until 8 PM PDT this evening CAZ270-278.

&&

$$