High Wind in California, May 28 to 29, 2022

Area Forecast Discussion
National Weather Service Las Vegas NV
256 PM PDT Sat May 28 2022

.SYNOPSIS...Gusty winds and cooler temperatures continue each
afternoon this weekend as a trough of low pressure digs over the
western states. Temperatures will bottom out on Monday before
increasing again next week.
&&

.SHORT TERM...Today through Memorial Day.

As a broad trough digs over the western CONUS, gusty winds continue
over the Desert Southwest, resulting in high fire danger in southern
Nevada and northwestern Arizona and recreation impacts to those
spending time outdoors this Memorial Day weekend. Winds overachieved
this morning, with gusts exceeding 40 mph starting around 7am in the
higher elevations of San Bernardino County. As high resolution
models suggested, there was a brief lull before picking back up in
time for the Wind Advisory issuance for much of San Bernardino
County and the eastern Sierra Slopes / Owens Valley. Winds are
behaving on par with expectations, with observed gusts over 45 mph
along Highway 395 south of Olancha and gusts in excess of 50 mph in
the higher elevations of western San Bernardino County. No changes
were made to today's wind headlines.

However, several additions were made to Wind Advisories for Sunday
afternoon across the region. As the trough axis moves overhead
tomorrow, as will a 115 kt 250mb jet. The ECMWF EFI highlights an
area of anomalous (between 80th and 90th percentile) wind gusts over
the southern Great Basin as a result, with ECMWF Ensemble, GEFS, and
hi-res members following suit with a band of enhancement from
Esmeralda, central Nye, southern Lincoln, over to northern Mohave
County. Looking at KTPH in Tonopah, many of these ensemble means
hover right around 40 mph (Wind Advisory threshold). Went ahead and
issued Wind Advisories for these zones tomorrow due to (1) winds
having over-achieved the last 2 days (2) 115 kt 250mb jet, with
synoptic signals for gusty winds along this belt from 500mb down to
850mb per the HREF (3) additional impacts possible due to Memorial
Day weekend, and (4) coordination with NWS Elko. This Wind Advisory
will go from 7 AM until 8 PM Sunday.

In addition to the Wind Advisory expansion across the southern Great
Basin, the Owens Valley in Inyo County and the Mojave Preserve and
Morongo Basin in San Bernardino County were added later Sunday
afternoon. This decision was less 'border-line' as the
aforementioned one, as the newest suite of high resolution models
favored 40+ mph winds over Highway 395 south of Olancha once again,
and gusts to 45 mph stretching further south and east across San
Bernardino County. This Wind Advisory will begin at 2 PM Sunday, and
will expire at the same time as the existing western San Bernardino
County product... at 11 PM PDT Sunday night. Echoing the previous
forecast discussion, HREF guidance continues to show a stark drop in
winds as they approach the Colorado River Valley, so kept the region
out of any wind or fire products.

No changes were made to the Red Flag Warnings, as enhanced fire
danger persists each afternoon, today and Sunday. Recreation
involving flames or sparks is ill-advised due to the high likelihood
of fire starts and spreads.

Wind speeds will be greatly reduced Monday afternoon, with
northwesterly post-frontal winds across the area. Memorial Day will
also be the coolest day of the forecast period, as ridging sets up
quickly behind the exiting trough.

.LONG TERM...Tuesday through Friday.

The Tuesday through Friday time period should be relatively quiet
as temperatures steadily rise from around 8 degrees below normal
on Tuesday to around 5 degrees above normal on Thursday before
plateauing. Expect dry conditions to continue with occasional
breezes as a persistent southwest flow sets up.
&&

.FIRE WEATHER...Strong afternoon winds and low afternoon relative
humidities will result in high fire danger each afternoon through
Sunday for most of southern Nevada and northwestern Arizona. Red
Flag Warnings persist from 12 PM to 8PM today and Sunday as a
result. Higher humidity will move into the Spring Mountains and
Sheep Range today, with values between 20 and 30 percent, but will
drop once again on Sunday. Sunday, the wind direction should shield
the Colorado River Valley from critical winds, mitigating fire
concerns there. Monday, wind speeds drop below critical thresholds.
&&

.AVIATION...For Harry Reid...Breezy southwest winds will continue
through this afternoon with the strongest winds expected through the
evening. Winds will decrease somewhat, but stay elevated overnight
before a cold front moves through the Valley tomorrow morning and
shifts winds to the northwest to prevail through Sunday. Right now
it looks like that shift would occur between 13Z and 15Z. SCT to BKN
clouds AOA 15kft will continue to move across the area into this
afternoon but should decrease to FEW AOA 25kft by this evening.

For the rest of southern Nevada, northwest Arizona and southeast
California...Gusty conditions will continue for all sites today into
tonight. For KBIH, winds will mainly be northerly throughout the
TAF period, although a westerly component may be seen for a few
hours after 21Z. Winds should return to the north by tonight.
Winds at KDAG will be westerly through the period with gusts over
40kts likely this afternoon and evening. Winds will be mainly
southwest to south at the lower Colorado River sites. Smoke from a
nearby wildfire may reduce visibilities at times at KEED and
blowing dust will be possible at KDAG. SCT to BKN clouds AOA 15kft
will continue to move across the area into this afternoon and
early evening but should decrease to FEW AOA 25kft by late this
evening at all sites.
&&

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

SHORT TERM...Varian
LONG TERM...Salmen
AVIATION...TB3

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