Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 200302

Area Forecast Discussion
National Weather Service Las Vegas NV
801 PM PDT Sun Aug 19 2018

.SYNOPSIS...Breezy southwest winds will develop across the region by
Monday afternoon. A weak push of monsoon moisture is expected late
Monday into Tuesday. This will bring a slight increase in
shower/storm chances through Tuesday for areas from Las Vegas east.
Breezy and drier conditions are expected through the remainder of
the week.

The remaining isolated showers and storms over Mohave County have
dissipated in the last couple of hours. Another day of above normal
temperatures is expected on Monday as the ridge remains situated
over the area for the first half of the day. Breezy, southwest winds
are expected on Monday afternoon as we become wedged between the
ridge, which will begin to shift eastward, and a deepening trough
over the Great Basin. The next influx of moisture looks to begin
late in the day on Monday and storms that do develop will likely not
get going until Monday evening into Monday night. Only minor changes
were made to the previous forecast.

.SHORT TERM...Today through Tuesday.

Just a few very isolated showers/storms have developed thus far
this afternoon. This is likely to continue through sunset before
quickly diminishing with the loss of daytime heating. Hot
conditions will continue into Monday. Increased southwest flow is
expected to result in breezy southwesterly winds across the region
by Monday afternoon. Gusts of 30-40 MPH will be possible across
portions of southern Nevada.

By Monday evening, a weak push of monsoon moisture will begin to
move into the area. A few evening/overnight showers will be
possible with this push.

The best chances for shower/thunderstorm activity will be on
Tuesday afternoon, generally from Las Vegas east. It currently
appears that a relatively sharp moisture boundary will be present
on Tuesday afternoon, which could act as a focus for initiation.
Storm motion will be to the northeast at 15-20kts which will
decrease the overall flood threat. The big question is will storms
be able to sustain development with the increased southwesterly

.LONG TERM...Wednesday through Sunday.

The latest medium range models indicate that monsoonal moisture will
be primarily confined to northwest Arizona from Wednesday on as a
south-southwest flow keeps moisture away from most of southern
Nevada and southeast California during the middle to latter part of
the week. This is due to a persistent trough over the Pacific
Northwest which will keep the mid level high over New Mexico and
Texas. The GFS is a little drier than the ECMWF and if it proves
closer to reality...there will not be sufficient moisture over
Mohave County to support thunderstorms by the weekend. Temperatures
will be near or slightly above normal during the period.

.FIRE WEATHER...Just a few isolated showers and stray thunderstorms
are expected this afternoon over northwest AZ. Otherwise hot and
dry conditions are expected through Monday. Increased southwesterly
flow is expected across the region Monday into Tuesday, with the
strongest gusts of 30-40 MPH across portions of southern NV. This
combine with dry air and drying fuels will result in near critical
fire weather conditions. A weak push of monsoon moisture will move
across the region late Monday through Tuesday, resulting in a slight
uptick in shower/storm potential, mainly from Las Vegas east. Breezy
conditions and slow drying are likely for the latter part of the

.AVIATION...For McCarran...Dry conditions with light winds
following close to typical diurnal trends are expected through
tonight. Speeds should remain around 10 knots or less for the
period. A few cumulus towers will be found over the mountains.
Gusty southwest winds are expected to develop Monday afternoon,
with speeds 15-20 knots and gusts up to 30 knots possible.

For the rest of southern Nevada, northwest Arizona and southeast
California...Light winds following diurnal trends are expected
through tonight. Gusty southerly winds will likely develop Monday
with speeds between 15-25 knots and gusts up to 35 knots possible.
The strongest wind speeds will be across Nye, Lincoln and the higher
elevations of Clark County. Similar gusty southerly winds are
expected again on Tuesday.

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


LONG TERM.................Adair

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