083
FXUS65 KVEF 011158
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
458 AM PDT Tue Jul 1 2025

.KEY MESSAGES...

* Hot temperatures continue Today but will be moderating
  thereafter.

* Increasing moisture will result in a return of thunderstorm
  chances through Thursday.

* Initial storms today across Northwest Arizona and the southern
  Great Basin will be quite dry and result in dangerous fire
  weather conditions.

&&

.DISCUSSION...through early next week.

Another hot day is in store today but the pattern will begin to
change with cooler conditions starting Wednesday through the
remainder of the week. Today`s afternoon highs will mirror values
seen Monday, topping out 3-8 degrees above normal. Meanwhile,
increasing moisture and the approach of a low pressure system will
result in temperatures cooling sharply Wednesday through Friday.
Highs will cool 4-8 degrees from their early week peaks during
this time, ending up closer to seasonal normal for early July, or
perhaps slightly below. As the low pressure system exists over the
weekend, heights will rebound and temperatures will resume an
upward trend, ticking back above normal by early next week.

As mentioned above, moisture will be on the increase especially
today and Wednesday. This is due to combination of the Four
Corners high setting up to our east, and a low pressure system
moving in from the west. This will induce a southerly flow across
the region, advecting deeper mid-level moisture into much of
southern Nevada and Northwest Arizona, and the eastern fringes of
the Mojave Desert across California. Storm coverage today will
favor Northwest Arizona as well as the Southern Great Basin, but
only very limited rainfall is expected due to the dry lower
atmosphere in place. With a hot and dry boundary layer,
atmospheric profiles will be quite conducive to strong outflow
winds which could potentially exceed 50 mph under the stronger
storm cores. As moisture transport increases Tuesday night into
Wednesday, storms will gradually trend wetter. The approaching
low pressure system will encourage nocturnal showers and isolated
storms across parts of Southern Nevada Tuesday night into
Wednesday morning that will spread slowly eastward through
Wednesday afternoon. Drier conditions will move in from west to
east Wednesday night into Thursday, with storm chances becoming
limited to Mohave County by Thursday afternoon.

The other concerning aspect with the thunderstorm activity,
particularly this afternoon and evening, is the risk for dry
lightning and strong outflow wind gusts. HREF probabilities paint
the greatest storm coverage across Northwest Arizona this
afternoon and evening, with a secondary corridor of weaker but
potentially gustier storms along the Nye/Lincoln County line.
Probabilities for outflow winds exceeding 30 knots range from
70-90% in these areas, with about a 10-20% chance for 50 knot
gusts. While coverage of lightning activity is uncertain,
especially across the Southern Great Basin, was inclined to issue
a Red Flag Warning for Dry lightning risk for Lincoln and Mohave
Counties given the seasonal peak in fuel danger, RH, outflow winds
and lightning risk.

&&

.AVIATION...For Harry Reid...For the 12Z Forecast Package...After
light winds this morning, another round of gusty winds is
expected this afternoon through early evening, with gusts expected
to top out between 20-25KT. The primary concern is potential for
thunderstorms to develop this afternoon and early evening along
the Spring Mountains, which could potentially send outflows across
the Valley. Of additional and more substantial concern is an
outflow boundary pushing westward into the Valley during the early
evening. Confidence is higher in this scenario, though
uncertainty remains regarding timing and precise magnitude and
direction of the winds. VFR conditions are expected to prevail,
with increasing mid-level clouds this afternoon onward.
Temperatures will exceed 100 degrees between 19Z-04Z, with a
maximum of 107 degrees around 23Z.


For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...Gusty southerly to
southwesterly winds will develop once again this afternoon, with
gusts to 20-25KT common at area terminals. Gusts will largely
diminish after sunset, with the exception of the Western Mojave
Desert, including KDAG, where westerly gusts look to persist
overnight. Additionally, thunderstorms across northwestern Arizona
could send an outflow boundary westward during the early evening,
potentially impacting locations across the Colorado River Valley
and Las Vegas Valley with a brief easterly to southeasterly wind
shift. Precise timing and magnitude remains in question, and
trends will bear watching. Otherwise, away from storms and outflow
boundaries, VFR conditions prevail with increasing mid and upper
level clouds through the period.

&&

.FIRE WEATHER...Increasing mid level moisture will bring a risk of
dry thunderstorms to much of Northwest Arizona and Lincoln County
this afternoon and evening. Storms which develop will produce very
little rain but strong outflow wind gusts over 50 mph are
possible. Incoming low pressure will also bring strong surface
winds to Esmeralda county. Surface RH will be quite low area wide
bottoming out in the 5 to 15 percent range outside of the highest
elevations above 10kft. All this while fuels are reaching their
climatologically most vulnerable levels. Given the above
concerns...a Red Flag Warning has been posted for Fire Weather
Zones NV460, 461, 462, and AZ101.

&&

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

&&

$$

DISCUSSION...Outler
AVIATION...Phillipson

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