771
FXUS65 KVEF 030232
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
731 PM PDT Sun Jun 2 2024

.SYNOPSIS...High clouds will slowly increase across the region today
and Monday before clearing out Tuesday. Mostly clear skies are
expected through late-week. Temperatures will increase through the
week with very hot conditions Wednesday and Thursday. Temperatures
will moderate closer to seasonal averages over the weekend.
&&

.UPDATE...Areas of high clouds continue to stream in this evening as
a potent shortwave moves into the PacNW. Other than cloud cover and
a slight uptick in winds on Monday, we won`t see much from this
system. As it moves east early this week, upper-level ridging will
build in behind it, dominating the weather over the Western US. Main
story will be the heat, with Excessive Heat Watches posted for most
of the Mojave Desert on Wednesday and Thursday. By Friday, the
temperature forecast becomes more uncertain as a cutoff low begins
to funnel in increased moisture and cloud cover. Confidence in a
slight cooldown increases over the weekend with PoPs increasing to 5-
15%. &&

.DISCUSSION...Today through next Sunday.

A shortwave trough axis will pass through the forecast area this
afternoon, allowing temperatures to cool 3-5 degrees across the
region. Meanwhile, a late-season atmospheric river event occurring
in the Pacific Northwest will usher in a few high clouds to the
Desert Southwest today before a swath of high clouds cover the
region on Monday. Precipitation chances are little-to-none, as we
continue to experience very dry low-levels of the atmosphere.

The aforementioned shortwave trough will continue eastward as a
ridge of high pressure builds over the region. As such, temperatures
will slowly climb through the work week, reaching excessive values
by Wednesday and Thursday. For context, the current high temperature
forecast for Las Vegas on Thursday is 111, with a 77% chance of 110
or higher. This would tie the earliest 110 observed in Las Vegas on
record - previously occurring June 6th, 2010. The current high
temperature forecast for Death Valley is 120. This would not be the
record earliest occurrence; however, Death Valley`s first 120 of the
season is normally June 15th, so it would be an earlier-than-normal
occurrence. Excessive Heat Watches remain in effect for Clark County
(with the exception of the mountains), the Colorado River Valley,
southern Mohave County, San Bernardino County, southern Inyo County,
and far southern Nye County Wednesday and Thursday. Major HeatRisk
expected in our desert valleys on Wednesday. An additional day of
Major HeatRisk on Thursday increases the level to `Extreme` due to
the body`s inability to cool off, thus resulting in higher instances
of impacts. This level and duration of heat affects everyone without
adequate cooling or hydration. It is also of note that this is the
first heatwave of the season, meaning it is likely that neither the
resident population nor the tourist population have had ample time
to acclimate to these temperatures.

Our northern zones including the Owens Valley, Esmeralda County,
central Nye County, Lincoln County, northern Mohave County and the
mountains of Clark County will continue to be considered for heat-
related products. Presently, HeatRisk in these locations is
`Moderate`, with only elevations above 6000 ft experiencing Minor
HeatRisk. Those hoping to escape from the heat to the higher
elevations should still take precautions such as drinking plenty of
water and taking frequent breaks in the air conditioning.

Uncertainty persists regarding Friday`s forecast. There is good
agreement that a weak closed low will push into Baja California.
Disagreement lies in the strength and positioning of this low as it
moves inland. Temperatures on Friday will depend on the amount of
moisture (by way of cloud cover or isolated thunderstorms) that
moves into the Desert Southwest. A weaker and further south
trajectory of this low would result in persistent hot temperatures
and would increase the likelihood of extending excessive heat
products into Friday.

Regardless, this low will work to drop temperatures across the
forecast area through the weekend.
&&


.AVIATION...For Harry Reid...Light south to southeast winds are
expected through the afternoon. It is possible that winds could go
more easterly at times before shifting more definitively south
shortly before sunset. Similar winds are expected Monday, although
the shift to southerly could come a bit earlier than today. A shift
to a north or northeast direction is expected Tuesday morning, with
speeds remaining light. No operationally significant clouds or
weather expected through Tuesday, although high clouds are expected
to blanket the area late Monday before thinning out and dissipating
Tuesday morning.

For the rest of southern Nevada, northwest Arizona and southeast
California...South to southwest winds gusting 15 to 25 knots are
expected through this afternoon. Monday, winds will increase a
little areawide, with the strongest gusts of 25 to 30 knots over the
Sierra Nevada crest and in the Barstow area. For Tuesday, most of
the region will see lighter winds, but Inyo, Esmeralda, and central
Nye counties will see northerly winds gusting 20 to 25 knots. No
operationally significant clouds or weather expected through
Tuesday, although high clouds are expected to blanket the area from
north to south on Monday before thinning out and dissipating Tuesday
morning.
&&


.FIRE WEATHER...Minimum relative humidity values below 15% this
afternoon will increase to 10-20% Monday and Tuesday before
returning to the single-digits midweek. Wednesday and Thursday,
expect high temperatures 10-15 degrees above seasonal averages and
overnight relative humidity recoveries between 20 and 30%. South-
southwest afternoon breezes each day through the week with gusts
between 15 and 25 mph.
&&


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

&&

$$

UPDATE...Woods
DISCUSSION...Varian-Soulat
AVIATION...Morgan

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