Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 241851
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1151 AM PDT Fri Jun 24 2022

.SYNOPSIS...Isolated shower and storm activity will persist over
northwestern Arizona through the weekend as the region taps into
some early-season monsoonal moisture. Otherwise, temperatures will
hover a few degrees above seasonal averages, with general afternoon
breeziness expected through the forecast period.
&&


.DISCUSSION...Today through Thursday.

Another round of isolated shower and thunderstorm activity expected
this afternoon, but will be restricted to the southern Sierra Nevada
crest as well as Mohave County in Arizona. CAPE values in these
areas will range from 500 to 700 J/kg this afternoon. Greatest
anticipated impacts will be in Mohave County, where forecast HRRR
inverted-V soundings show over 1200 J/kg of DCAPE with around 0.75"
of PWAT. At least initially, rain that falls will struggle to reach
the ground, due to evaporation through the dry low levels. Gusty
outflow winds will be the primary concern. As showers persist and
the column moistens, the potential for small hail will arise, with
about 700 J/kg of mixed layer CAPE, though severe hail is unlikely.
As mentioned in the previous discussion, Saturday`s convection looks
to be very similar in nature to today`s as far as intensity, areal
coverage, and location, though there is an increased chance of an
isolated shower or thunderstorm in the panhandle of Lincoln County
with modest CAPE values.

Sunday, ridging builds over the area from the southeast Pacific,
pushing convection opportunities further east. Though chances of
isolated showers and thunderstorms persist for Mohave County through
the early part of next week, chances will remain on the eastern
fringes of the county, if initiating in Mohave at all. Meanwhile,
temperatures will increase to a few degrees above seasonal averages
across the Mojave and southern Great Basin deserts with general
afternoon breeziness returning each day. "Moderate" HeatRisk
expected below 5000 feet in elevation through midweek, meaning an
increased risk of heat-related illness.

Of note, Tropical Storm Celia persists in the southeastern Pacific
Ocean, anticipated to develop into a hurricane early Saturday
morning. Details will become more clear as we progress through the
weekend, but depending on the exact track that Celia takes, coupled
with the high pressure placement/eastward progression over the Four
Corners, there may be enough of a moisture flux to increase PoPs
over our forecast area mid-week. Though the NBM is not currently
sold, the ECMWF ensemble means favor measurable precipitation across
portions of southern San Bernardino County and up the Colorado River
Valley, with PWATs between 1.00 and 1.50 inches. Stay tuned!
&&


.FIRE WEATHER...Fire concerns remain concentrated to Mohave County
as well as the southern Sierra today. In the Sierra, the primary
hazard will be dry lightning strikes. Though gusty winds are
possible from area thunderstorms, afternoon RH values will range
from 30 to 40 percent, helping to mitigate fire concerns. Across
Mohave County, dry lightning as well as afternoon RH values in the
single-digits on the western side of the county - increasing to
lower 20s on the eastern fringes - will be present alongside gusty
outflow winds from storms that develop. Storm potential greatly
diminishes with sunset.
&&


.AVIATION...For Harry Reid...Breezy south to southwest winds are
expected this afternoon, with gusts 20-25KT expected. Winds will
dissipate after sunset, with typical overnight wind trends expected
tonight. Diurnal winds trends are likely for Saturday with wind
speeds of 8KT or less. Occasional afternoon clouds around 12kft are
possible, otherwise skies will be clear through the period.

For the rest of southern Nevada, northwest Arizona and southeast
California...Isolated convection is possible in western Arizona this
afternoon as well as along the Sierra ridgeline. Any thunderstorms
could contain lightning and sudden gusty winds. Elsewhere, it will
be dry today. Expected breezy south to southwest winds with gusts 20-
25KT this afternoon.

Any thunderstorms that develop this afternoon will dissipate this
evening. Mostly clear skies and typical wind trends return for
tonight and Saturday morning across the region.
&&


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

$$

DISCUSSION...Varian
AVIATION...Nickerson

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