Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 060312 AAA
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
811 PM PDT Mon Jun 5 2023

.SYNOPSIS...Isolated convection will occur today over the high
terrain in Inyo, Esmeralda, Nye, and Lincoln counties which could
produce some gusty outflows in those areas. Elsewhere, partly
cloudy skies and above average temperatures continue with KLAS on
100-watch. After today, temperatures drop substantially to well
below normal and remain there through the next several days. Isolated
thunderstorm probabilities continue through the week, mostly for
the Sierra and central Nevada.
&&

.UPDATE...Scattered showers and isolated thunderstorms will likely
continue well past midnight across Inyo County and south central
Nevada as upper low stalls over southern California. Main impact
from the storms today as been gusty winds as several sites have
recorded peak winds of 50-55 mph. Will send out an update for the
rest of tonight.

Upper low will remain stationary over southern California tomorrow.
Models do show drier air getting wrapped into the low over southern
Nevada and northwest Arizona which should limit convection. The only
exception will be over the southern Sierra/Owen Valley. Cooler
tomorrow, highs some 5-8 degrees lower than today.
&&

.SHORT TERM...Today and Tomorrow.

Another day of isolated thunderstorms looks likely for the high
terrain areas of Inyo, Esmeralda, Nye, and Lincoln counties for
the most part. Synoptically, a weak but broad area of UL lifting
is overhead due to closed low off the coast of California. This,
coupled with marginal instability should again produce storms
through the afternoon in these areas. As of 18Z, GOES satellite
indicated cu in these areas, very much in line with the 12Z HREF
CI timing. Of note from the 12Z suite of hi-res model inputs, the
HRRR/FV3 both produced a stout outflow generated from a storm
originating in the White Mountains, that could come to impact KBIH
later this afternoon. Opted to make these modifications in the TAF
and grids as well for the Bishop area. The higher end estimates
were around 40 mph gusts, but this would all be due to one
particular storm, so tempered the deterministic forecast a bit to
account for that uncertainty. Elsewhere, QPF will be a bit hard to
come by given HRRR forecast soundings showed very little SB or
MLCAPE, meager mid level lapse rates, and only mid level moisture
to tap into. Inverted V profiles in some cases above 600 mb will
be very hard to rain through. Surface dew points should continue
to tank as low level dry air filters in from the south and
southeast this afternoon, hopefully scouring out any storm
potential for Clark County and south.

Outside of storm potential, the forecast high of 99 will be
closely watched by many as the prospect of 100 will be on the
minds of many. This is particularly interesting because...as
discussed in the long term...below normal temperatures are set to
stay through the end of the month, and that *could* mean that
today is the best probability for 100 for the rest of the month.
The current record for the latest first 100 for KLAS is June 30th,
so that might be in play if today doesn`t reach the century mark.
Per the 13Z NBM, the probability for 100 this afternoon is ~10%,
meaning 90% of the outcomes it produces kept the high at 99 or
below.

After today, much cooler temperatures will be in store compared to
today and the weekend as the low comes on shore and approached the
Great Basin. This will continue to keep the Sierra in focus for
additional thunderstorm development under the low with low top
convection expected. WPC has indicated the Sierra in a "marginal"
risk for heavy rainfall through Day 5 as a result, with even some
very high terrain new snow possible each day as well.


.LONG TERM...Wednesday through Sunday.

Not our typical June pattern forecast through the long term as
ensemble simulations continue to advertise a persistent trough over
the region. Lower than normal heights will keep temperatures some 5-
10 degrees below normal. Mid-level moisture and cooler temperatures
aloft will lead to daily convection primarily over the southern
Sierra and central Nevada mountains. However over the upcoming
weekend, its possible that threat could extent further south into
Spring Mountains and mountains of northwest Arizona. One benefit
from the cooler than normal temperatures is that snowmelt runoff
will stay reduced below what could be otherwise occurring at this
time of year.

Looking beyond Sunday. It looks as if the area will be locked in
this pattern well into the second full week of June as CPC shows a
higher chance of below normal temperatures and a higher chance of
above normal precipitation persisting through June 18.
&&

.AVIATION...For Harry Reid...Gusty southeast winds are expected
through much of the afternoon hours, with variability in direction
between 120-170 through sunset. Gust potential could reach as high
as 30 kts at times this afternoon as well. After sunset, winds are
expected to diminish below 10 kts and shift to a more south-
southwest orientation overnight. Southeast winds are expected to
return again by tomorrow morning, with lesser gust potential than
today...up to 20 kts.


For the rest of southern Nevada, northwest Arizona and southeast
California...Gusty afternoon winds are expected for all terminals
today, with isolated TSRA possible in the vicinity of KBIH. KBIH
may also experience some strong gusty outflow winds after 23Z this
afternoon due to vicinity TSRA. Elsewhere, winds are expected to
generally subside after sunset with similar conditions expected
tomorrow.

&&

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

$$

UPDATE...Pierce

SHORT TERM/AVIATION...TB3
LONG TERM...Pierce

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