Flash Flood Warning 329, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
102 PM PDT Sat Oct 15 2022

.SYNOPSIS...Widespread showers and thunderstorms, some with gusty
winds and heavy rain, can be expected through tonight across the
Mojave Desert and Northwest Arizona, generally south of Las Vegas.
Drier conditions will resume by Sunday afternoon with the
exception of a stray shower in Northwest Arizona. Dry and warm
conditions will dominate most of next week until the next weather
system arrives Friday.

&&

.SHORT TERM...through Sunday night.

Thunderstorm event for our southern zones is underway this
afternoon as a dynamic cut-off low pressure system creeps inland
near the northern Baja coastline. Most of the activity through the
morning hours has been concentrated across Mohave County, though
with continued destabilization and easterly wrap around flow on
the northern periphery of the cut-off low, expect activity to
spread into San Bernardino County in the coming hours. With 25-35
knots of deep layer easterly shear, cool mid-level temps, and
strong diffluence aloft, the stage is set for multiple rounds of
thunderstorms, some of which could be severe with strong wind
gusts and hail. Thunderstorms will tend to focus south of a
Barstow-Las Vegas-Peach Springs line, with the best chances for
severe weather and flash flooding generally south of I-40.

Widespread rainfall and embedded thunderstorms will persist across
our far southern zones and Northwest Arizona much of the night
tonight, though activity will tend to become more showery through
the morning in Mohave county as the low pushes eastward, with
improving conditions likely through the day. Elsewhere, dry
conditions are expected but temperatures will drop closer to
seasonal normal thanks to the widespread precipitation overnight
and reduced heights with the low pressure system in the vicinity.
Any remaining shower activity will quickly die off by sunset
Sunday.

.LONG TERM...Monday through next weekend.

Most of next week will be dry and mild with a a gradual warming
trend as afternoon highs return to several degrees above normal.
This will be thanks to an expansive western conus ridge that will
build across the area through midweek. By Thursday and Friday, yet
another cut-off low pressure system will be lurking off the
Southern California coast, and most model guidance suggests it
will slowly creep inland by Friday into Saturday. Current
indications are that this cut-off system will be slightly weaker
than the one moving through today, but may still provide enough
dynamic forcing for some a stray shower or two as it moves
inland, along with a modest cooling trend. Beyond Saturday,
ensemble model agreement degrades though there is some hints that
northern stream energy may attempt to clip through the Great
Basin, which could bring with it some gustier winds and a shot of
more fall- like temperatures.

&&

.AVIATION...For Harry Reid...Increasing clouds expected through
the afternoon and evening with thunderstorm activity expected
south of the Las Vegas Valley. While thunderstorms are not
expected at the terminals, south or southeasterly outflow winds
remain possible, and gusts up to 20 knots would be possible.
Storms south of Vegas may impact air traffic in the Peach Springs
and Daggett corridors. Conditions will gradually improve overnight
with light winds and just a few clouds expected Sunday,

For the rest of southern Nevada, northwest Arizona and southeast
California...Sierra and Great Basin region will enjoy peaceful
flying conditions today with light winds and few clouds expected
at KBIH. More challenging conditions exist across the Mojave
Desert and Colorado River Valley where afternoon and overnight
thunderstorm activity is likely along with CIGS in the 7-10kft AGL
range. Locally strong winds gusts exceeding 30 knots are possible
through the early evening. Conditions will gradually improve from
west to east overnight.

&&

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

DISCUSSION/AVIATION...Outler

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