298
FXUS65 KVEF 240311
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
811 PM PDT Sun Jun 23 2024

.SYNOPSIS...Hotter than normal temperatures will continue through at
least the middle of next week. Isolated showers and thunderstorms
will be possible this afternoon and evening for eastern Lincoln
County and areas south and east of the I-15 corridor. The anomalous
moisture responsible for today`s showers and thunderstorms will
gradually be pushed out of the area throughout the week, which will
result in gradually decreasing coverage when it comes to
precipitation chances.

&&

.UPDATE...Convective intensity continues to wane across eastern
Mohave County as the sun sets and meager lift persists along the
outflow boundary. Radar trends and CAMs suggest this activity will
diminish completely over the next 2-3 hours. Tomorrow, similar
conditions are expected, with most convection along and south of the
I-15 corridor, but the Sierra/White Mountains and eastern Lincoln
County may come into play as well during the afternoon. Main
concerns will continue to be gusty outflow winds, lightning, and
isolated flash flooding. Monsoonal activity lingers through
Wednesday until southwesterly flow scours out the moisture on
Thursday. Temperatures remain above normal through at least early
July.

&&

.SHORT TERM...through Tuesday.

Anomalous moisture combined with strong daytime heating will bring
the first taste of the monsoon to portions of our forecast are this
afternoon. Isolated showers and thunderstorms are expected across
Mohave County this afternoon and evening as well as portions of
Clark, Lincoln, and San Bernardino Counties. Convection will favor
areas of higher terrain for development with the potential for
isolated instances of flash flooding should thunderstorms remain
anchored to the terrain with continued redevelopment. Moderate to
heavy rain and flash flooding are not the only threats with today`s
storms. Relatively dry air near the surface will provide a favorable
environment for strong gusty outflow winds with any convection that
does develop. Additionally, lightning will pose a threat to those
without adequate shelter in the vicinity of any thunderstorms that
develop. Given that heating is the driver of today`s convection,
showers and thunderstorms will begin to slowly dissipate after
sunset this evening.

Another round of monsoonal convection will be possible tomorrow
afternoon and evening for Mohave County and southern San Bernardino
County as anomalous moisture remains in place overhead. The Eastern
Sierra and Spring Mountains will see a 15 to 20% chance of afternoon
showers and thunderstorms as this moisture attempts to push further
north before it gradually retreats back towards the east. As this
moisture begins to retreat, so will precipitation chances. By
Tuesday afternoon precipitation chances will be limited to the
eastern portions of Mohave County.

The aforementioned strong daytime heating partially responsible for
this first taste of the monsoon will also be responsible for hotter
than normal temperatures continuing through the middle of the week.
Afternoon temperatures will top out around 5 to 8 degrees above
normal for the next few days with overnight low temperatures up to
10 degrees warmer than normal.

.LONG TERM...Wednesday through next weekend.

By mid-week, a trough is forecast to move into the PacNW and begin
to flatten the ridge over the Rockies. As this occurs, flow aloft
transitions from southerly to southwesterly, resulting in the
advection of drier air into our CWA. However, moisture doesn`t
really get scoured out until Thursday, leaving overlap on Wednesday
of the monsoonal moisture and subtle cooling/jet dynamics from the
PacNW shortwave. This overlap may be enough to provide the most
widespread convection within this first taste of the monsoon. Latest
EPS and GEFS highlight southern Nevada and northwest Arizona, along
with the Sierra and White Mountains, with 30-80% PoPs on Wednesday.
Ensemble mean PWATs on Wednesday range from 0.75" in our
northwestern areas to 1.50" in the lower Colorado River Valley.
These values, roughly 200% of normal, should support this potential
for greater convective coverage.


&&

.AVIATION...For Harry Reid...Winds will be primarily from the south
today with gusts of 15 to 20 knots in the afternoon. There is a low,
but not zero, chance of thunderstorm outflow winds from the south or
east affecting the terminal this evening. If this does not occur,
typical south southwest winds are expected overnight. Similar
conditions are expected Monday.

For the rest of southern Nevada, northwest Arizona and southeast
California...Southerly winds gusting 15 to 25 knots are expected
over areas northwest of Interstate 15 this afternoon, weakening
overnight. Southeast of Interstate 15, scattered thunderstorms are
expected, likely producing outflows which will disrupt the winds and
possibly causing poor visibility in blowing dust. These storms will
also produce isolated ceilings below 8000 feet with associated
terrain obscuration. Slightly less thunderstorm coverage is expected
Monday, with similar conditions otherwise.

&&

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

&&

$$

UPDATE...Woods
SHORT TERM...Stessman
LONG TERM...Woods
AVIATION...Morgan

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