719
FXUS65 KVEF 150923
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
223 AM PDT Tue Oct 15 2024

.SYNOPSIS...Dry and warm conditions continue through midweek when a
drastic change in the weather pattern cools temperatures, elevates
south-southwesterly winds, and increases precipitation chances for
the Desert Southwest heading into the weekend. Higher elevations of
southern Nevada may experience their first snowfall of the season.
&&


.SHORT TERM...Today and Wednesday.

A weak closed low over the southeastern Great Basin / eastern Mojave
Desert will result in fairly consistent heights over the region,
thus only minor changes in forecast high temperatures between
yesterday and today. This weak low will push eastward out of the
Desert Southwest on Wednesday as the region gears up for a change in
the overall synoptic pattern. Meanwhile, a longwave trough will set
up in the western CONUS associated with a center of low pressure
located over southeastern Alaska / western British Columbia. As this
is occurring, a shortwave embedded in the main trough will push
through the Desert Southwest on Wednesday, resulting in elevated
south-southwest winds with gusts between 25 and 35 mph.

.LONG TERM...Thursday through next Tuesday.

The first significant storm of the fall season will be taking shape
on Thursday as a trough originating in the Gulf of Alaska drops into
Northern California and Nevada by the afternoon. This will lead
to gusty south-southwest winds at least 25-35 mph across most of
the region and high temperatures dropping several degrees into the
lower to mid 80s for the Mojave Desert zones...which is close to
normal.

Model ensembles are in fairly good agreement that the system will
undergo cyclogenesis and bring considerable moisture with it as
it dives and closes off over southern Nevada Thursday night and
Friday leading to scattered-to-numerous showers developing over
southern Nevada and northwestern Arizona as temperatures drop an
additional 10-15 degrees and snow levels lower to around 5500-6000
feet. There will likely be at least a dusting of snow, and
possibly a few inches of snow accumulation, for the mountains of
southern Nevada and northwestern Arizona...especially Lincoln and
northern Mohave counties adjoining the southwestern Utah border
where PoP values are highest at 50-70 percent Thursday night and
Friday. North winds generally gusting 30-40 mph will combine with
the showers to produce a cool and blustery day with high
temperatures topping out in the upper 60s to lower 70s for the
desert zones and overnight lows in the 50s. The first freeze of
the season appears likely over central and northern Lincoln County
and also the northern Owens Valley Friday night.

The majority of medium-range ensembles indicate the low will be
somewhat stationary as it circulates over southern
Nevada/northwestern Arizona Saturday then slowly lifts away to
the Four Corners Sunday, so moisture wrapping around the system
may produce a more prolonged period of showers than implied by the
decreasing 20-30 percent PoPs currently in the grids.

A dry weather pattern returns under zonal flow Monday and Tuesday
and temperatures will climb back to near-normal. &&


.AVIATION...For Harry Reid...Light winds at 8KT or less that follow
typical wind patterns are expected today through Wednesday morning.
Winds will become east-northeast this afternoon then transition to
the typical southwest direction around sunset. Skies will be clear
through the period.

For the rest of southern Nevada, northwestern Arizona and
southeastern California...In general, typical wind patterns are
expected across the region today and tonight. KBIH will see
elevated south-southeast winds this afternoon around 10KT with
occasional gusts to 15-20KT. KDAG will continue to see west winds
around 10KT through the morning before light winds set up this
afternoon. Typical west winds around 10KT will push back into KDAG
between 04-06Z tonight. The Colorado River Valley sites will
favor a northerly direction this afternoon. KEED will remain at
8KT or less wind speeds this afternoon; however, KIFP could see
speeds around 10KT, especially this morning through midday.
Typical wind patterns return across the area tonight. VFR skies
will continue through the period across the region.
&&


.FIRE WEATHER...South-southwest winds will increase across the area
on Wednesday, which will combine with dry conditions and cured
vegetation to increase fire danger in southern Nevada. Afternoon
relative humidity values will range from 10 to 20% with overnight
recoveries exceeding 45%. As such, a Fire Weather Watch is in effect
from 11am to 8pm PDT on Wednesday.
&&


.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.

&&

$$

SHORT TERM...Soulat
LONG TERM...Adair
AVIATION...Nickerson

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