978
FXUS65 KVEF 221825
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1125 AM PDT Wed May 22 2024

.SYNOPSIS...Seasonal temperatures with periods of gusty winds
expected through the weekend. Most locations remain dry, but
isolated showers and storms will be possible in our northern areas
Friday and Saturday. High pressure builds in next week, resulting in
above-normal temperatures and dry conditions.

&&

.DISCUSSION...through Tuesday.

Persistent, long-wave troughing over the Western US with embedded
shortwaves will keep things mildly active through Saturday. The
first shortwave passes through the PacNW and Northern Great Basin
today, spurring breezy conditions across most of the CWA. Peak wind
gusts of 20-30 mph are forecast this afternoon as temperatures
remain close to seasonal normals. Zonal flow behind this system
brings a slight reduction in winds and temperatures Thursday, but
another shortwave makes its approach on Friday. Unlike its
predecessor, this trough is expected to extend down through our CWA,
bringing a greater likelihood of impactful winds. Latest NBM
probabilities paint the typical SW wind belt (I-15 and I-40
corridors) with widespread 40-80% chances of 40+ mph winds. When
bumping that threshold up to 48 mph, probabilities drop below 20%
outside of the high terrain, suggesting any wind impacts are likely
to be minor in nature. However, any boaters getting an early start
to the holiday weekend should be prepared for increased wave action
on Friday. Given the warm and largely dry weather of late, there is
also some concern for elevated fire weather conditions, primarily in
the lower elevations of the Colorado River Valley and NW Arizona
where fuels are beginning to cure.

In the areas not expected to see gusty winds with the late-week
system, we`ll be watching for scattered showers and isolated
thunderstorms to develop. Friday afternoon, 10-30% PoPs stretch from
Northern Inyo County to Lincoln County. Ensemble guidance has the
trough dragging just enough moisture into the Southern Great Basin
to spur this activity in conjunction with the colder air/forcing
aloft. While ensemble mean PWATs are 120-150% of climatology, that
isn`t saying much for late May around here. As a result, any impacts
from this convection would be gusty outflow winds and lightning. On
Saturday, this potential becomes focused in East-Central Nevada.

As Sunday rolls around, the aforementioned system will be east of
the Rockies. In its wake, 500mb heights rise rather quickly as
ridging begins to build over the Western US. WPC Cluster Analysis
suggests good ensemble agreement in a large-scale pattern shift
taking hold next week as the ridge dominates the regional weather.
ECMWF meteograms for Las Vegas show the entire ensemble temperature
distribution above the 50th percentile of model climatology by the
middle of next week, suggesting a high likelihood of above-normal
temperatures.

&&

.AVIATION...For Harry Reid...A period of moderate (8-15kts)
southeast winds (140-170) is possible through 21Z before becoming
southwest with gusts to around 20kts after 21Z. Expect the southwest
winds to persist into tomorrow morning before turning to the north
after 14Z. South to southwest winds should return after 22Z
tomorrow. VFR conditions will prevail through the TAF period.

For the rest of southern Nevada, northwest Arizona and southeast
California...Las Vegas Valley TAF sites will follow similar trends
to KLAS. KBIH will see south winds into mid-afternoon before turning
more westerly after 21Z.  North winds will return after 03Z and
continue through Thursday morning.  At KDAG, westerly winds will
continue through the TAF period, with gusts over 20kts developing
after 20Z.  TAF sites in the Colorado River Valley will have mainly
south to southwest winds through the period, with occasional gusts
to 20kts this afternoon and again Thursday afternoon.

&&

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

&&

$$

DISCUSSION...Woods
AVIATION...Planz

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