-- Discussion containing changed information from previous version are highlighted. --
093
FXUS65 KVEF 172032
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
132 PM PDT Mon Jun 17 2024

.SYNOPSIS...A transient weather system will bring gusty conditions
and cooling temperatures to the region today and Tuesday, with
afternoon highs dropping below 100 for all but the lowest
elevations Tuesday afternoon. Thereafter, high pressure will
gradually rebuild with increasing potential for major heat impacts
by next weekend for much of the region.

&&

.DISCUSSION...
-- Changed Discussion --
Through next Monday.

Mostly clear skies over southern Nevada and the Mojave Desert as an
upper trough/shortwave moves through northern Nevada. Associated
cold front running from near Ely-Beatty-Lone Pine with gusty
northwest winds filling in behind the cold front. Meanwhile, pre-
frontal gusty southwest-west winds are continuing throughout far
southern Nevada, eastern California deserts and northwest Arizona.
Still expecting FROPA in the Las Vegas Valley between 8 pm and 10 pm
this evening.

Those gusty northerly winds will linger through at this Tuesday
morning before they begin to subside during the afternoon hours.
Cooler air filtering in behind the front will give the area a brief
reprieve from the hottest start to a June since 2013. Temperatures
quickly rebound back to normal Wednesday.

Finally, we have been monitoring smoke from the Post and Hesperia
Wildfires in southern California. Latest HRRR Smoke output suggests
much of the smoke/haze will affect southern San Bernardino and
Mohave Counties the rest of this afternoon and tonight. If both
fires remain active the HRRR suggests more favorable trajectory for
smoke/haze to work back toward southern Arizona Tuesday.

For the long term we are monitoring the influx of `monsoon` moisture
into at least Arizona by weeks end and the return of `hot`
temperatures areawide. An inverted trough over the western Gulf of
Mexico, in the Bay of Campeche is progged to move west across
mainland Mexico reaching the eastern Pacific/Sea of Cortez Friday.
Lower level moisture progged to reach eastern Arizona Thursday and
continue west toward Mohave County Friday. Some guidance suggests
potential for a secondary influx from a gulf surge advecting
moisture up the lower Colorado River over the weekend. This will
need to be closely watched this week but for now NBM does have a
slight chance of thunderstorms over the higher terrain of eastern
Mohave County each day Friday-Monday.

Building heights under the subtropical ridge will lead to another
period of well above normal temperatures with highs approaching 110
degrees on Saturday. Highs at or greater than 110 degrees are in the
forecast Sunday through Tuesday. Las Vegas probabilities of 110
degrees or higher are at 50% or greater Saturday through next
Thursday. As such, expect widespread `Moderate` HeatRisk, while some
desert valleys return to `Major` HeatRisk on Saturday and beyond.
Excessive Heat products may be needed.
-- End Changed Discussion --

&&

.AVIATION...
-- Changed Discussion --
For Harry Reid...Gusty southwesterly winds will
continue through the afternoon hours with gusts to around 25 knots.
A cold front will move through the area this evening, causing winds
to shift to the northwest with gusts over 20 knots possible after
about 03Z. Wind will begin to diminish during the early morning
hours and become lighter around 10kt from the northeast Tuesday
afternoon periods of FEW to SCT high clouds will pass over the area
through the TAF period.

For the rest of southern Nevada, northwest Arizona and southeast
California...  Gusty southerly to southwesterly winds continue this
afternoon in the Las Vegas Valley and Colorado River Valley. Winds
at these locations will shift to the north to northwest this evening
with the passage of a weak front. Gusts accompany the frontal
passage but should subside later in the night. At KDAG, winds remain
gusty out of the west through the evening. Elevated smoke from
wildfires in southern California may spread over KDAG but should
have minimal impact on aviation. In the Owens Valley including KBIH,
winds maintain a northerly direction with an increase in gusts in
through the evening then decreasing overnight. FEW-SCT high clouds
will pass over much of the forecast area through Tuesday morning.
-- End Changed Discussion --

&&

.FIRE WEATHER...
-- Changed Discussion --
Very dry conditions will persist today with
minimum relative humidity dropping below 15% for most areas this
afternoon and evening. A Red Flag Warning remains in effect for
AZZ101-102 today due to the very dry conditions and persistent gusty
winds resulting in high fire start and spread risk. Sustained winds
in northwest Arizona will likely exceed 20 mph for much of the day.
Elsewhere, it will be dry but winds will struggle to jump to
impactful levels for an extended period of time and fuels remain
marginal. NVZ460 could reach Red Flag Warning criteria briefly this
evening and early overnight; however, due to the short-lived threat
held off on the issuance.
-- End Changed Discussion --

&&

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

&&

$$


DISCUSSION...Pierce
FIRE WX...Outler
AVIATION...Berc

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter