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621
FXUS65 KVEF 252004
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
104 PM PDT Tue Jun 25 2024

.SYNOPSIS...
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Moisture influx will return showers and thunderstorms to
the forecast area today. Highest flash flood threat will be in
northwestern Arizona and highest damaging wind gust threat will be
in southeastern California. Precipitation chances will dwindle
and above-average heat will continue as we move through the week.
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.SHORT TERM...
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Today.

Another round of isolated showers and thunderstorms expected this
afternoon as anomalous moisture pushes northward deeper into our
region coupled with CAPE values between 500 and 1000 J/kg. PWATs
will approach 200% of normal by the end of the day. This moisture
coupled with very hot conditions will be enough for isolated
convection across southern Nevada and northwestern Arizona today.
The 12Z Las Vegas sounding indicated a convective temperature of
104. As of 11:45am, the temperature in Las Vegas was 108 and
isolated thunderstorms have already been noted across Mohave County
this morning. Mohave and Lincoln counties will have the highest
threat of flash flooding, while Inyo, Esmeralda, and Nye counties
will have the highest threat of damaging wind gusts.

Continuing to see a strong signal in Convection-Allowing Models
(CAMs) of an outflow boundary kick off from storms in central
Arizona later this afternoon, which would push northwestward into
Mohave County and southern Nevada. This outflow will bring with it
gusty winds, moist air, and is likely to perpetuate shower and
thunderstorm chances into the evening as storms form along its
boundary.

.LONG TERM...Wednesday through Monday.

Shower and thunderstorm chances return Wednesday afternoon but with
less areal extent as a shortwave trough originated from the Pacific
Northwest pushes moisture eastward out of our area. This shortwave
will increase southwest winds in the Mojave Desert Thursday and
Friday afternoons. Winds will remain sub-advisory, but will work to
increase fire danger. Precipitation chances linger in far eastern
Mohave County on Thursday before the remainder of the week dries out
beneath a dry northwesterly flow.

Meanwhile, heat remains a persistent impact in the Desert Southwest.
Temperatures will remain above-average through the entire forecast
period with HeatRisk remaining "Moderate" or higher for desert
valleys through the week and weekend.
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.AVIATION...
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For Harry Reid...The latest model guidance indicates an
increased risk of thunderstorm development near the Vegas Valley
this afternoon, mainly over the higher terrain south and east of
the valley. Development is not expected before 20Z, and the main
impacts to the field would be outflow winds from 130-190 degrees
and speeds up to 40kts. If thunderstorms do not develop, winds
should remain southerly with occasional gusts up to 20kts. There
is also the potential for outflow winds from 110-160 degrees after
02Z from distant thunderstorms expected over northwest Arizona.
Winds return to a more typical diurnal overnight and Wednesday,
with only a slight chance (10-15 percent) of convection affecting
the valley. Maximum temperatures of 109F to 111F are expected both
today and Wednesday.

For the rest of southern Nevada, northwest Arizona and southeast
California...Scattered thunderstorms are expected over northwest
Arizona, southern Nevada, and southeast California this afternoon
and early evening, with KBIH having the highest probability of being
directly affected by thunderstorms. The main concern will be gusty,
erratic winds, along with brief heavy rainfall and CIGs below 8kft
AGL occasionally obscuring terrain. Away from convective activity,
south to west winds with occasional gusts of 20 to 25 kts are
expected.  Similar conditions are expected tomorrow, although
convection should be limited to northwest Arizona and areas north
and east of Las Vegas in southern Nevada.
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.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.

&&

$$

DISCUSSION...Soulat
AVIATION...Planz

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