284
FXUS65 KVEF 150345
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
845 PM PDT Sun Jul 14 2024

.SYNOPSIS...Isolated to scattered afternoon thunderstorms will
redevelop around the region Monday then drier air gradually moves,
limiting thunderstorm activity primarily to northwest Arizona
Tuesday and Wednesday. Monsoon moisture may slowly spread back into
the region later in the week, leading to increasing chances for
thunderstorms over southern Nevada and southeast California.
&&

.UPDATE...Recent radar loops indicate thunderstorms have dissipated
across our forecast area this evening with only lingering isolated
light showers or virga. The latest HRRR/HREF support a fairly
tranquil night though we will need to keep an eye on influence of
large convective complexes in southwest Arizona. Moisture only
decreases slightly Monday and we lose some of the stronger southerly
convergent flow aloft as the coastal trough lifts over northern
California. There will still be fuel for afternoon thunderstorms,
with slightly less activity than today. The forecast trends detailed
in the previous discussion are supported by the latest NBM and no
immediate changes are needed. -Adair
&&

.PREV DISCUSSION...
228 PM PDT Sun Jul 14 2024

.SHORT TERM...Today and Tomorrow.

Anomalous monsoonal moisture remains in place over the region as we
continue to find ourselves under southerly flow aloft thanks to the
ridge of high pressure positioned over the Four Corners Region and a
low pressure system off the coast of California. Precipitable water
on this morning`s sounding remains around 150% of normal for this
time of year, which will help fuel another round of isolated
convection this afternoon and evening. As was the case yesterday,
the lack of moisture in the lower levels, as indicated by the
inverted V-shape in the lower-levels of the sounding, means that
strong gusty outflow winds will be possible with any storms that
develop today. Mesoanalysis indicates that DCAPE values across the
area are currently around 1,000 to 1,500 J/kg and are expected to
increase as we heat up this afternoon, a further indication of an
elevated convective wind threat. An increased threat for dry
lightning remains across the southern Great Basin and eastern Sierra
through this evening due to this drier air near the surface.
Isolated flash flooding will be possible in the southern and eastern
portions of our forecast area where moisture is more abundant. With
convection largely being driven by daytime heating, thunderstorm
activity will begin to die down a couple of hours after sunset.

Moisture will begin to slowly retreat back to the east on Monday
as the upper-level ridge flattens out. This will limit
precipitation chances with afternoon showers and thunderstorms
being even more isolated tomorrow. Eastern Mohave County and the
higher terrain of Clark and eastern San Bernardino counties will
have the best chances of showers and thunderstorms tomorrow
afternoon with a 20% to 40% chance of precipitation.

With the upper-level ridge remaining in place over the Desert
Southwest, temperatures will continue to run a few degrees above
normal.

.LONG TERM...Tuesday through Sunday.

Upper-level flow will continue to become drier through Tuesday,
limiting precipitation chances to high terrain over northwest
Arizona. Afterwards, ensembles seem to show moisture creep back
into the area as flow becomes more favorable again later in the
week. As of now the greatest precipitation potential later this
week is in northwest Arizona and southern Nevada over high
terrain. Temperatures remain above normal and increase by several
degrees through the week. Pockets of Major (Level 3) HeatRisk
appear again on Wednesday in low elevations along the Colorado
River.

&&

.AVIATION...For Harry Reid...Scattered areas of convection will
continue through the remainder of the afternoon. Direct impacts to
the airfield are possible although gusty outflow winds from nearby
storms have a high (greater than 70%) probability of causing impacts
to the terminal area. The convection is expected to end earlier
today than Saturday, with most storms dissipating by 02Z. Southwest
winds will develop this evening and become light and variable
overnight. Northeast winds will redevelop by late morning on Monday.
Isolated convection is also possible again on Monday, but coverage
should be less than what occurred this weekend and should be
confined to mainly the higher terrain.

For the rest of southern Nevada, northwest Arizona and southeast
California...Scattered thunderstorms will continue to develop across
much of the region today and persist through sunset before
diminishing. Any storms will be capable of producing lightning,
brief periods of heavy rainfall, CIGs less than 10kts that could
obscure areas of higher terrain, and sudden gusty outflow winds.
Away from areas of convection, south-to-west winds 10kts to 15kts
with occasional gusts to 20kts can be expected with winds overall,
diminishing after sunset and fall below 10kts across the region
overnight. Additional thunderstorms are possible on Monday, but
coverage is expected to be more limited, with most storms remaining
over northwest Arizona or the higher terrain of southern Nevada.

&&

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

&&

$$

SHORT TERM...Stessman
LONG TERM...Meltzer
AVIATION...Salmen

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