Calico Basin, Nevada Weather Forecast Discussion

225
FXUS65 KVEF 210927
AFDVEF
Area Forecast Discussion
National Weather Service Las Vegas NV
227 AM PDT Sun Sep 21 2025
.KEY MESSAGES...
* Slight chances for showers and thunderstorms persist each day
  through the forecast period, as anomalous moisture remains over
  the region.
* Today, best chances of showers and thunderstorms exist south and
  east of Interstate 15.
&&
.DISCUSSION...Today through Saturday.
A cut-off low off the coast of central California will slowly push
southward over the next few days. With the monsoonal high positioned
over north-central Mexico, this results in a southwest flow aloft,
as the Desert Southwest sits between these two systems. Over the
next few days, the cut-off low will continue to inch toward the
coast as it pushes southward. As it does so, several instances of
vorticity maxima will shred off of the low and move along the flow
aloft, allowing for enhanced instability over our forecast area.
This is relevant, because anomalous moisture will remain in-place
over our forecast area through the week, with PWATs between 150 and
200 percent of normal. As a result, there exist slight chances of
showers and thunderstorms each day through the upcoming work week,
favoring the higher terrain. There remains low confidence in the
forecast mid-to-late week, as shower and thunderstorm chances are
highly dependent on the exact trajectory of the aforementioned
closed low as it moves inland. Otherwise, temperatures will remain
at-or-slightly below normal, with generally light afternoon breezes.
Today, best chances of showers and thunderstorms exist south and
east of Interstate 15, as this is where the best instability exists
(with 85-100 kt winds at 250mb and modest vorticity advection).
Clearing skies this morning will allow for CAPE values between 250
and 500 J/kg and 500mb shear between 20 and 30 kts. Expect generally
light-to-moderate rainfall with occasional lightning in San
Bernardino, southern Clark, and Mohave counties today, but cannot
rule out locally heavy rainfall and more frequent lightning with
storms that form over the higher terrain.
&&
.AVIATION...For Harry Reid...For the 06Z Forecast Package...Light
southwesterly winds will continue through early tomorrow morning
when winds will become light and variable before transitioning to
the southeast around mid-morning. Breezy southwesterly winds will
pick up in the afternoon with sustained speeds of 10 to 12 knots
gusting to around 20 knots. During the early afternoon winds will
likely vary between southeasterly and southwesterly before
finally settling in from the southwest around mid-to-late
afternoon. These breezy southwesterly winds will continue into
the evening when wind gusts will drop off with winds continuing to
maintain a southwesterly direction through the evening. VFR
conditions will prevail with mid-to-high clouds pushing into the
area during the afternoon and sticking around through the evening.
For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Overall, winds will
remain relatively light, 12 knots or less, and will follow typical
daily directional trends through late Sunday morning/early Sunday
afternoon when breezy southerly to southwesterly winds will pick
up with wind gusts around 15 to 25 knots. Areas south and east of
the Interstate 15 corridor will see a band of showers move through
beginning tomorrow morning and continuing through early Monday
morning. The Colorado River Valley TAF sites are the most likely
to see vicinity showers with the potential for light rain showers
starting tomorrow afternoon. Low confidence as to whether showers
will get close enough to DAG to have any impacts, but if DAG were
to see impacts it would likely be between mid-morning and
afternoon. Increasing mid and high clouds aoa 10 kft will
accompany these showers.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...Soulat
AVIATION...Stessman
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NWS VEF Office Area Forecast Discussion