-- Discussion containing changed information from previous version are highlighted. --
081
FXUS65 KVEF 211921
AFDVEF

Area Forecast Discussion National Weather Service Las Vegas NV 1212
PM PDT Tue May 21 2024

.SYNOPSIS...Moderate north winds and a few degrees of cooling
will occur today behind a low pressure system moving away toward the
Rockies. A mean trough will hold over the western states this week
into the holiday weekend resulting in near normal temperatures with
elevated afternoon winds each day.
&&

.SHORT TERM...
-- Changed Discussion --
through Thursday.

Broad upper level trough will sit over the region through the next
few days. No precipitation is expected through Wednesday night as
dry west to northwest flow dominates the weather pattern. A wave
embedded in the mean flow will dip down and pass through the region
late Wednesday into Thursday. The main piece of energy will only
brush the Southern Great Basin as it moves through central Nevada
Thursday so no widespread impacts are expected with this system. The
pressure gradient will tighten with the wave`s passage so increasing
south to southwest winds are expected Wednesday later afternoon and
on Thursday. Probabilities for impact wind gusts over 40 MPH are
little to none (<10%) across much of the region with the only hint
of potential wind impacts being in the Western Mojave Desert where
there is some low to moderate end (40%-50%) probabilities for wind
guts over 40 MPH per the NBM ensembles runs. Other ensembles such as
HREF and ECMWF Ensemble show lowed probabilities or limit the higher
probabilities to the higher terrain. Based on the overall synoptic
set up, this scenario with the low winds would make more sense.
Expected isolated wind gust impacts such as crosswinds and patchy
blowing dist at times Wednesday and Thursday late afternoons in
central portions of San Bernardino County, including around Daggett,
CA, where winds may gust up to 35 MPH at times...however widespread
wind impacts are not expected.

Other than the winds, expect mostly sunny skies son Wednesday before
some mid to upper level moisture works into the Southern Great Basin
on Thursday with the main piece of energy. Further south, it will
remain mostly sunny on Thursday. Temperatures Wednesday and Thursday
will warm slightly compared to today`s temperatures, with high
temperatures expected to be right around normal for this time of the
year.

.LONG TERM...Friday through Monday.

Lower 500 mb heights and general "troughiness" will linger across
the Desert Southwest through the weekend. Breezier afternoon
winds will continue through Saturday as shortwaves embedded in the
upper level flow continue to pass through the Great Basin. These
lower 500 mb heights combined with a series of passing
disturbances to our north will keep temperatures in the normal to
slightly cooler than normal range as we head into the weekend.

Long term guidance is hinting at the 500 mb pattern becoming more
zonal or potentially ridge-y Sunday onward. This would result in
warming temperatures and the continuation of dry and relatively mild
weather into early next week.
-- End Changed Discussion --
&&

.AVIATION...For Harry Reid...Breezy N/NE winds today, gradually
weakening weakening in the afternoon and evening hours. Probability
of 20+ knot gusts drops below 20% by ~20z this afternoon. Light NE
winds turn to the W/NW tonight, with speeds remaining below 10 knots
through tomorrow morning. S/SW breezes return tomorrow afternoon
with a 60% chance of gusts over 20 knots. Clear skies.

For the rest of southern Nevada, northwest Arizona and southeast
California...N/NE winds forecast at all the TAF sites this
afternoon, with the strongest winds in the Colorado River Valley.
Speeds gradually weaken through the afternoon and evening hours,
with most sites falling below 10 knots tonight. Most likely
exception to this will be KDAG, where west winds around 10 knots
persist through the night. Breezy W/SW winds return to the region
tomorrow. VFR conditions and clear skies prevail.

&&

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

&&

$$

SHORT TERM...Nickerson
LONG TERM...Stessman
AVIATION...Woods

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter