056
FXUS65 KVEF 170828
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
126 AM PDT Thu Jul 17 2025

.KEY MESSAGES...

* An higher levels of monsoonal moisture today through Saturday will
  result in increased chances for afternoon showers and
  thunderstorms, some of which could produce locally heavy rains and
  gusty winds.

* Temperatures fall to below-normal levels today and Friday,
  followed by a gradual rebound to near normal levels over the
  weekend.

&&

.DISCUSSION...through Wednesday.

A cut-off area of low pressure off the coast of Baja California will
help to push monsoonal moisture into the region over the next few
days.  This increased moisture will allow for scattered showers and
thunderstorms to develop this afternoon and evening across southern
Nevada, northwest Arizona, and far eastern southern California.
PWATs continue to increase early this morning, and by this
afternoon, values around 1.5" are expected as far north as the Las
Vegas Valley.  Instability will also increase today, with afternoon
CAPE values expected to be around 750 J/kg in the Vegas area and
around 1100 J/kg over central and southern Mohave County. Scattered
showers and a few isolated storms are likely over southern Mohave
County this morning, and by early afternoon, convection should
develop further north into southern Nevada.  Given the high PWAT
values in place (approaching 200% of normal), heavy rainfall that
could produce flash flooding will be of concern in some of the
heavier storms, along with gusty winds exceeding 50 mph. Further to
the northwest over central Nye and Esmeralda counties, there will be
enough instability to trigger a few storms. However, given the lower
moisture levels that will be present, gusty winds will be the
primary concern. DCAPE values in this area will be around 1500 J/kg,
supporting isolated gusts exceeding 60 mph.  Similar conditions are
expected on Friday as the deep moisture remains in place. Over the
weekend, moisture levels are expected to decrease as the upper low
moves into southern Arizona and weakens.  A few scattered storms are
still possible on Saturday, but coverage will be less and mainly
confined to eastern areas of the CWA.  Mainly dry conditions are
expected from Sunday on with a few isolated storms possible over far
eastern portions of the CWA.


The increased moisture levels across the area today and tomorrow
will help to keep maximum temperatures below normal.  Some places,
including Las Vegas, are not expected to see highs exceed 100
degrees F on both days (there is a 60 percent chance that Las Vegas
will remain below 100 degrees F today). As the low mentioned above
weakens over the weekend, temperatures will rebound, but only to
near-normal levels. As of now, readings are expected to remain right
around normal through the middle of next week.

&&

.AVIATION...For Harry Reid...For the 06Z Forecast Package...The
primary aviation concern this forecast period will be
thunderstorms that could impact the Las Vegas Valley during the
afternoon and early evening. Gusty, erratic outflow winds and
lightning are expected, potentially impacting the terminal even
from distant storms, with brief downpours producing MVFR or IFR
conditions also possible. Timing details will be refined in later
issuances. Otherwise, southerly winds will prevail outside of
storms, with sustained speeds 10-12KT and gusts to 15-20KT late
morning through the evening. VFR conditions and ceilings around
12kft are expected away from convection, with improvement in
ceilings expected overnight with lighter winds through daybreak.


For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Las Vegas Valley
terminals generally follow similar trends to KLAS, with
thunderstorms expected to develop during the afternoon and early
evening. The main concerns will be lightning and erratic, gusty
outflow winds. Showers and storms look to impact the Lower
Colorado River Valley and Mohave County beginning mid to late
morning, with an uptick in convection during the afternoon.
Outside of storms, winds across the region will generally be
southerly to southeasterly, with gusts to around 15-25KT,
particularly during the afternoon. The exception will be across
the Western Mojave Desert, including KDAG, where westerly winds
tonight will veer to the east late morning, before returning to
the southwest after 03Z. VFR conditions will prevail away from
convection, with FEW-BKN clouds around 10-15kft.

&&

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

&&

$$

DISCUSSION...Planz
AVIATION...Phillipson

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