Scientific Forecaster Discussion
fxus65 kvef 221657
Area forecast discussion
National Weather Service Las Vegas Nevada
857 am PST Mon Jan 22 2018
Synopsis...breezy conditions will persist for the next couple
of days along the Colorado River valley with dry conditions and
seasonal temperatures expected across the region. A quick moving
weather system will move through the area late Wednesday and
Thursday bringing chances of light snow over the southern Sierra and
the southern Great Basin as well as breezy to locally windy
conditions to much of the area.
fairly quiet weather is expected to start the work week as a weak
ridge settles over the area. Breezy conditions down the Colorado
River valley will prevail today through tomorrow; becoming gusty
each day. Speeds should remain around 15 knots gusting 25 knots with
isolated gusts up to 30 knots possible around the Bullhead
City/Laughlin area. Below normal temps this afternoon will warm back
up to seasonal norms tomorrow. No significant changes needed to the
current near term forecast.
Short term...today through Wednesday night.
Ridging will continue over the area through Wednesday morning before
the next system sends the ridge axis east and brings increasing
southwest flow aloft Wednesday and Wednesday night.
Gusty north winds are expected along the Colorado River valley today
through Wednesday morning before they turn back to the south during
the day Wednesday in response to the next incoming system. The north
winds are not expected to be significant and no wind hazard products
will be needed. It could be a different story by mid week as a
potent shortwave moves to the West Coast Wednesday night. There is
plenty of time to watch the forecast unfold before any need to take
Dry weather conditions are expected through Wednesday with an
increasing chance of showers Wednesday night.
Temperatures will remain cool across the area today, remaining
several degrees below normal before moderating with a warmer airmass
in place. However, light winds and poor mixing of the boundary layer
will lead to valley inversions and daytime temperatures struggling
to warm each day. MOS temperature guidance for Tuesday and Wednesday
is likely overdone in valley locations except over the northwest County Warning Area
on Wednesday where gusty afternoon winds should help mix warmer air
aloft to the surface.
Long term...Thursday through Monday.
A fast moving Pacific trough with limited moisture is expected to
move across the region Thursday, but impacts will be minor and
confined mainly to the southern Sierra and south central Nevada
zones. The latest medium range models depict that this trough will
be slightly less amplified than indicated the past couple days and
most of the moisture will be intercepted by the west slopes of the
southern Sierra. It is a relatively cold trough and the cold pool
will brush central and southern Nevada Thursday with possibly a few
snow showers across central Nye and Lincoln counties. Widespread
southwest winds will develop ahead of the trough axis, but the
latest National and local wind models indicate gusts will generally
be in the 25-35 mph range except higher in the mountains. There will
be some strong downslope potential for the Owens Valley early
Thursday, but confidence is low at this time.
Temperatures will drop 5 degrees or so Friday on the back side of
the trough then a ridge will build over our region through the
weekend allowing temperatures to rebound back a little above normal
with highs generally in the 60s across the Mojave Desert zones.
Sustained north north winds 15-25 mph can be expected down the
Colorado River valley from Laughlin-Bullhead City to Lake Havasu
through the weekend.
Aviation...for McCarran...variable winds generally less than 7
knots can be expected today and tonight under occasional high clouds.
For the rest of southern Nevada, northwest Arizona and southeast
California...most of the region will see variable winds less than 10
knots today and tonight under occasional high clouds. The exception
is along the Colorado River valley from Laughlin-Bullhead City
southward where gusts of 20-25 knots can be expected late morning
through the afternoon.
Spotter information statement...spotters are encouraged to report
any significant weather or impacts according to Standard operating