Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 280230
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
730 PM PDT TUE SEP 27 2016

.SYNOPSIS...An area of low pressure will slowly move up the Gulf of
California and into southeast California by tomorrow afternoon
before lifting into the Great Basin on Thursday. Scattered showers
and thunderstorms will be possible across the area through Thursday
before becoming more localized later in the week. Temperatures will
generally be within few degrees of normal into Saturday.
&&

.UPDATE...Upper low to our south continues to throw moisture across
the southern part of the forecast area with a few showers and a
thunderstorm or two this evening. Coverage is still fairly limited
however. Cannot really argue too much with inherited forecast based
satellite/radar and latest model output. Slight chance to chance
pops still look okay across a good portion of Mohave County along
with eastern San Bernardino County and portions of Clark County as
the upper low continue to move slowly north into southern
California. No updates anticipated this evening. -Harrison-
&&

.PREV DISCUSSION...
249 PM PDT TUE SEP 27 2016

.SHORT TERM...through Thursday Night.

Little change in forecast thinking, thus have made only minor tweaks
to the ongoing forecast.

An area of low pressure near the northern tip of the Gulf of
California will continue drifting north and likely a bit west as
well for tomorrow. As it does so, it should draw additional moisture
into the region. When combined with decaying cloud deck, this should
result widespread weak to modest instability. Flow will be
transitioning from easterly to weak flow (except for southwest flow
in Mohave county) as the low moves into southern California and
begins to shear apart. This will result in weakening dynamics.
Overall, expect scattered showers with a few thunderstorms. Areas
that are able to get more sun and/or any boundaries that develop
would be the focus for any stronger/heavier thunderstorm activity.
Expect the heaviest rainfall amounts in Mohave county.

The low will continue to shear and lift out thursday, with generally
decreasing coverage of shower chances. Some additional moisture may
make it into Mohave county, but will likely stay well to the
southeast.

.LONG TERM...Friday through Tuesday.

The latest indications from the medium range models are that
moisture will be swept out a little more quickly Friday as a dry and
stable southwest flow develops ahead of a broad trough centered off
the Pacific Northwest Coast. Pops were trimmed accordingly with only
a few showers possibly hanging on over Lincoln and Mohave counties
Friday afternoon. A progressive pattern will then lead to the broad
trough moving across the Great Basin Saturday and Sunday followed by
a west-northwest flow early next week. The primary effect this will
have on our region is increasing southwest winds with breezy to
windy conditions Saturday and Sunday along with a modest cooling
trend. There are some differences between the GFS and ECMWF
solutions on the progression and depth of the trough...with the
ECMWF slower than the GFS. Little change was made to the wind and
temperature grids which are weighted toward the ECMWF.
&&

.FIRE WEATHER...A low pressure system moving in from the south
today will increase moisture for most of the area by Wednesday.
Shower and thunderstorm chances will initially enter northwest
Arizona and southeast California today...overspread the area
Wednesday...then decrease as the area dries out from west to east
through the end of the week. Some easterly breezes remain possible
across the far western Mojave Desert. There is the potential for a
stronger wind event over the weekend and will be monitoring for
potential fire weather concerns.
&&

.AVIATION...For McCarran...A circulation moving from southwest
Arizona over southern Nevada tonight and Wednesday will produce SCT-
BKN clouds with bases 8-12 Kft. Occasional light showers will be
around the terminal area...primarily Wednesday. There will be the
potential for showers to produce erratic winds at times with speeds
up to 20 knots but prevailing winds are expected to be from the east
or southeast less than 10 knots.

For the rest of southern Nevada...northwest Arizona...and southeast
California...A circulation moving from southwest Arizona up over
souther Nevada and surrounding states will produce SCT-BKN clouds
with bases 8-12 Kft. Scattered light rain showers and isolated
thunderstorms can be expected Wednesday.
&&

.SPOTTER INFORMATION STATEMENT...Shower and thunderstorm chances
will increase in Mohave County today, overspread most of the area
Wednesday and begin decreasing the rest of the week. Spotters are
encouraged to report rainfall amounts and any other significant
local weather.
&&

$$

Short Term...........Steele
Long Term/Aviation...Adair
Fire.................Czyzyk

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