Area Forecast Discussion
Issued by NWS Las Vegas, NV
FXUS65 KVEF 241010
Area Forecast Discussion
National Weather Service Las Vegas NV
310 AM PDT MON OCT 24 2016
.SYNOPSIS...Showers and isolated thunderstorm activity will become
more scattered today and gradually diminish from west to east by
Tuesday early morning. Pleasant conditions will return Tuesday
through Thursday before more active weather returns Friday through
.SHORT TERM...Today through Wednesday Night.
A well-defined band of showers and embedded thunderstorms remains
stretched from Barstow to Pahrump to Pioche early this morning. This
band is being supported by stout upper level divergence courtesy of
left exit region dynamics associated with a 115kt jet streak off the
southern California coast. High-res guidance shows this band
weakening from south to north between 4AM and 8AM as focused upper-
level support diminishes. During this time, the band is not expected
to move significantly, drifting north slightly if anything. This
means that the threat of a messy morning commute in Las Vegas is
Overall, precipitation activity will become more scattered in nature
during the mid-late morning hours. This afternoon, some additional
instability should result in a slight uptick in scattered convective
precipitation across Lincoln, northern Mohave, and at least the
higher terrain of Clark counties, with isolated showers possible
elsewhere. As drier air begins to push in from the west, showers
should end from west to east late this afternoon through tonight.
For Tuesday and Wednesday, expect dry conditions with just a few
clouds and minor afternoon breezes. Temperatures will warm 1-3
degrees both days.
.LONG TERM...Thursday through Monday.
The medium range models are in good agreement that a broad trough
will be centered along the west coast Thursday which will produce a
dry southwest flow for most of southeast California and southern
Nevada. However, the ECMWF is now supported by the GFS model
indicating the potential for moisture to be drawn up ahead of this
trough over northwest Arizona and possibly southeast Nevada. The
origin of this moisture can be seen on recent satellite loops
associated with a circulation over west central Mexico. This
circulation, or inverted trough, is forecast to lift northward and
the western fringes of the moisture may spread over Mohave county
and eastern Lincoln county Thursday before being largely pushed
eastward Friday as the aforementioned trough progresses inland. Pop
values were increased slightly over Mohave and eastern Lincoln
counties...generally in the 15-25 percent range. Moisture spreading
into Clark county cannot be completely ruled out, but confidence is
too low to mention any weather for Clark county zones for now.
As the trough progresses inland...additional energy is forecast to
drop into its base Saturday and keep a weak mean trough over the
forecast area through Monday. This pattern will keep a dry southwest
flow over the region with slight cooling trend and breezy afternoons.
.AVIATION...For McCarran...Northwest winds will diminish through the
morning hours, likely turning to an east or southeast direction mid-
morning. Gusty southwest winds to 15-25kts will return this
afternoon. Isolated showers cannot be ruled out through this
evening, with the best chances between 16z-04z. CIGS should remain
in the 8-12kft range, resulting in periods of mountain obscurations.
Drier and calmer conditions are expected during the middle of the
For the rest of southern Nevada...northwest Arizona...and southeast
California...Well-defined band of precipitation stretching from KDAG-
KP38 will weaken somewhat by mid-morning, with shower activity
becoming more scattered after that time. CIGS generally 8-12kft,
with lower bases to 5-7k feet near stronger cells. Southerly winds
will increase area-wide once again this afternoon, gusting 15-25kts
in most areas, up to 35kts along ridgetops and across central
Nevada. Areas of mechanical turbulence and mountain obscurations
should be expected around high terrain. Drier and calmer conditions
are expected during the middle of the week.
.SPOTTER INFORMATION STATEMENT...Scattered showers and
thunderstorms are expected today. Spotters should report significant
weather according to standard operating procedures.
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