Swansea, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

412
FXUS65 KVEF 121903
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1202 PM PDT Sun Jul 12 2026

.KEY MESSAGES...

*  Showers and thunderstorms with gusty winds and lightning this
   afternoon and evening in the Sierra as well as through Mohave
   County.

*  Monsoonal moisture remains in place through the week resulting in
   continued chances for showers and thunderstorms.

&&

.DISCUSSION...Today through Friday.

Mesoanalysis this morning shows moisture advecting northward as
PWATs over 1.00 inch have reached the I-15 coordidor. On satellite,
amesovort can be seen spinning over southern California. This
shortwave is expected to move north today which should trigger
precipitation in Inyo County. The best forcing will be over the
Sierra crest but hi-res models do show some precipitation drifting
into the Owens Valley. Limited instability and moisture in this
area could hinder thunderstorms as mainly showers develop today.
With dry low levels though, gusty winds would still be possible
with these showers. Further east, the HRRR and RRFS remains
consistent that an outflow from north central Arizona with gusty
winds will trigger showers and storms that push west this evening.
Other hi- res models are not as robust with this feature, but
given the instability and available moisture, leaned towards the
HRRR/RRFS for this evening`s and and early overnight`s forecast.
This would bring gusty east winds and scattered showers and storms
through Mohave County after 5PM, then through the Colorado River
Valley after 7PM. Some runs do bring gusty east winds and isolated
showers or storms into the Las Vegas Valley after 9PM. HREF shows
a 50%-70% chance of gusts over 30 MPH in Mohave County with this
outflow and the Colorado River Valley, and has even introduced a
10% chance for gusts over 50 MPH in northern Mohave County. With
dry low levels, moderate instability, and wind vectors
perpendicular to the potential line of precipitation- agree with
these probabilities. Boaters on Lake Mead, Lake Mohave, and Lake
Havasu should monitor the forecast and be prepared to take action
if these winds and storms do move through this evening. Once this
feature dissipates tonight, it will be dry with quiet weather
tonight. Showers and thunderstorms are expected again Monday
afternoon and evening, with chances across much of the region as
moisture becomes more widespread. While the terrain will see the
highest risk for storms on Monday, development may depend on if
this incoming outflow tonight lays down any boundaries (which
could trigger development with destabilization Monday afternoon)
or if it leaves debris clouds (which could hinder afternoon storm
development). Much like today, storms Monday will bring a risk of
lightning, sudden gusty winds, and brief heavy rain as the
atmosphere continues to saturate. Temperatures will moderate back
to near normal, but note that overnight lows will run above normal
as moisture and potential lingering clouds from daytime
convection prevents efficient cooling.

Chances for showers and thunderstorms continues Tuesday through the
week as moisture remains in place across the region. Gusty outflow
winds, lightning, and brief heavy rain will be the main concern with
storms through midweek as forecast soundings don`t show decent
saturation until after midweek. After Wednesday, better saturation
in low levels are noted, In fact, long range ensembles hint another
uptick in moisture as the flow potentially picks up some moisture
form distant tropical systems in Pacific. There is also an easterly
wave transitioning through the mean flow late week that may or may
not move in Thursday onward. These ingredients will be important to
watch as they could allow for more organized convection and/or higher
rainfall impacts. At the moment, WPC has at least portions of the
area in a marginal risk for excessive rainfall through the end of the
week. Confidence in precipitation chances and potential thunderstorm
impacts decreases after Monday as mesoscale set ups each day and
uncertainty in longer range features will influence daily
convection.

&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...The
primary aviation concern this forecast period will be potential
thunderstorm outflow winds to impact the terminal this evening.
Until then, winds are expected to be south to southwest through much
of the afternoon with speeds generally around 10 knots with
occasional gusts between 15-20 knots. At this point, thunderstorm
chances this afternoon are <10%, but if they do develop gusty and
erratic outflow winds will be possible. The main concern will be
this evening between 03-06Z with a strong push of easterly winds
from thunderstorms in Arizona. Gusts between 20-30 knots are
expected with the low potential of seeing gusts exceeding 35 knots.
Temperatures will remain above 100F through 05Z with a high around
108F.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Most of the area will
see southeast to south winds through this afternoon with speeds
around 10 knots with higher gust to around 20 knots at times. AT
KBIH, upvalley gusts to around 30 knots are possible this afternoon.
Across the western Mojave/KDAG, winds will be around 5-10 knots and
somewhat variable before becoming gusty out of the west by mid-
afternoon. Thunderstorms are expected to develop over northwestern
Arizona this afternoon and evening, accompanied by erratic gusty
winds and lightning. Outflow from these storms will move westward
through the evening, potentially impacting KIFP/KEED and Las Vegas
Valley TAF sites mid- to late evening, with thunderstorms generally
confined to the higher terrain.

&&

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

&&

$$

DISCUSSION...Nickerson
AVIATION...Gorelow

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