NWS Las Vegas, NV wrote its last area forecast discussion before the first event at Jun 17, 7:40 AM PST, 4 hours 5 minutes earlier.
Area forecast discussion, Jun 17, 7:40 AM PST, 4 hours 5 minutes before
Area Forecast Discussion
National Weather Service Las Vegas NV
840 AM PDT Fri Jun 17 2022
.SYNOPSIS...Strong winds and critical fire weather conditions begin
this afternoon, lasting into Saturday for our Nevada and Arizona
areas. Cooler temperatures tomorrow and early next week, before
things warm back up. Calmer conditions next week.
&&
.UPDATE...Morning analysis features a 998mb surface low centered
near Esmeralda county as lee cyclogenesis takes form ahead of a deep
incoming Pacific trough. This surface low has set up an impressive
14.5mb surface pressure gradient between Bishop and San Fransisco,
which will manifest with increasingly gusty winds through the
afternoon - particularly across Inyo, Nye, and Esmeralda counties.
Blowing dust is a significant concern as winds increase in those
areas through the afternoon, though a veil of mid and high clouds
will hinder satellite detection capabilities.
Elsewhere, gusty winds with afternoon peak gusts of 40-50 mph still
look probable across San Bern, Clark, and Mohave counties and the
wind advisories in these areas look good. Dust could be a concern
here as well in the afternoon, especially near Dry Lake beds.
Aside from the wind, a thin layer of smoke has been noted across the
regional skies thanks to an ongoing fire in the Northern Baja. Most
of that smoke should tend to lift out through the day. Overall,
current forecast is in good shape but will be monitoring for the
need for any wind upgrades across our northern zones as well any
dust warnings if necessary.
-Outler-
&&
.SHORT TERM...Today through Sunday.
The main concerns in the short term will be the strong southerly
winds and subsequent fire weather conditions. An anomalously
amplified pattern is setting up across the western US, with a -2.5
sigma trough coming ashore on the West Coast and a +2 sigma ridge
dominating the central US. The resultant southwest flow over the
Sierra will produce lee cyclogenesis across northern Nevada,
inducing a N-S pressure gradient over our area. This will be the
driving factor behind the gusty south winds today. Hi-res guidance
shows widespread wind gusts in excess of 40 mph, with the potential
for gusts approaching 60 mph in Esmeralda, Nye, and Lincoln
Counties, as well as the eastern slopes of the Sierra. Strong winds
combined with low humidities are expected to yield critical fire
weather conditions across southern Nevada and northwest Arizona. On
Saturday, the pressure gradient relaxes a little, allowing wind
speeds to come down slightly. Gusts around 40-50 mph are still
expected, mainly across Lincoln, Clark, and Mohave Counties.
Critical fire weather conditions are expected on Saturday as well.
The winds finally begin to taper off on Sunday, with afternoon
breezes at a much more reasonable 15-20 mph, except in Mohave County
where gusts around 30 mph will linger.
If you manage to venture out into the wind, you'll notice cooler
temperatures, particularly on Saturday and Sunday. Highs today will
remain in the upper 90s and 100s for most of the area, near their
seasonal values. However, as the base of the trough moves in this
weekend, highs will fall to around 10 degrees below normal. Sunday
is shaping up to be the most pleasant day of the forecast period,
with a high in Las Vegas of 90F and light afternoon breezes.
.LONG TERM...Next week.
As we head into the work week, a calmer period of weather is
forecast. The system bringing the strong winds moves out, but a
broad trough will remain in place over the western US for a few
days. This should keep temperatures at or below normal for our area.
Afternoon breezes will be much more typical for this time of year,
with speeds around 10-20 mph. Later in the week, the upper-level
pattern becomes more zonal, allowing temperatures to warm a couple
degrees above normal. Models shows an elongated ridge building
across the south-central US later in the week, which may allow some
monsoonal moisture to creep into southeastern portions of our area
as southerly mid-level flow returns. Still a ways out, but ensemble
guidance show PWATs increasing at KIGM during this time.
&&
.FIRE WEATHER...Southerly winds ramp up today across the region.
Expecting widespread wind gusts in excess of 40 mph, with gusts
close to 60 mph possible in Esmeralda, Nye, and Lincoln Counties.
Combined with afternoon humidities of 5-10%, critical fire weather
conditions will occur across the area, with extremely critical
conditions possible in the areas of strongest winds. While not quite
as strong tomorrow, southerly winds will continue across the area.
Gusts over 40 mph are once again forecast for most of southern
Nevada and northwest Arizona, leading to another round of critical
fire weather. Afternoon humidities will be higher tomorrow across
the higher terrain of Mohave County, with values of 10-20%. There
is a small chance of an isolated shower/storm in Mohave County on
Saturday, which could produce dry lightning. Breezy winds
continue on Sunday in Mohave County, producing elevated fire
weather conditions. Winds finally subside on Monday. &&
.AVIATION...For Harry Reid...South winds will increase by 18Z
with gusts 25-30kts then become strong this afternoon from the
southwest with gusts up to 35-40kts at times and areas of blowing
dust into early this evening. Low level moderate turbulence can be
expected in the terminal area and PIREP solicitation is recommended.
Winds speeds should decrease after 04Z this evening with gusts
generally 20-25kts continuing overnight. Southwest winds gusting 30-
35 knots will redevelop Saturday late morning through the afternoon.
For the rest of southern Nevada, northwest Arizona and southeast
California...Widespread south-southwest winds gusting 30-40 knots
will develop late this morning through the afternoon and early this
with localized gusts of 45 kts and extensive blowing dust. Low level
moderate turbulence can be expected for all TAF sites. Winds speeds
will decrease to 15-25 knots this evening and overnight followed by
widespread southwest winds gusting 25-35 knots Saturday.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
DISCUSSION...Woods
AVIATION...Adair
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