Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 180452

Area Forecast Discussion
National Weather Service Las Vegas NV
952 PM PDT Sat Mar 17 2018

.SYNOPSIS...Upper low moving through the area tonight will bring
a good chance of rain, and snow to elevations above 5000 feet in
Lincoln and Mohave Counties. Calmer, drier and warmer conditions are
expected Monday and at least Tuesday as high pressure builds over
the area. A plume of moisture off the Pacific will bring an
increasing chance of rain and high mountain snow to the area
Wednesday through Friday.

.UPDATE...Scattered to numerous showers were occurring primarily
across central and northern Mohave County this evening just ahead of
the center of the cold pool circulation and associated front
currently moving across southern Nevada. Lake Mead and northeast
Clark County were also seeing some light showers. 3 hour Rainfall
amounts in central Mohave County were generally 0.04-0.08" with a
few sites reaching 0.16-0.20". North winds have developed down
through Desert Rock and Indian Springs indicating that frontal
passage will occur across Clark County over the next few hours. Most
of the showers will focus over northeast Clark and northern Mohave
counties, but cannot rule our a few light showers brushing central
Clark as the upper circulation moves overhead. The going forecast
has the situation covered quite well and will only make minor tweaks
to weather and wind grids based on the latest observations and high
res winds. -Adair


.SHORT TERM...through Monday night.

Quite a mixed bag of weather across our expansive area, which covers
the southern Great Basin and Mojave Desert. Rain/snow showers
occurring primarily across Lincoln County currently. But, satellite
does show area extending as far west as Esmeralda/northern Inyo
Counties. Elsewhere, its a mix of sun/clouds, winds and cooler

Most favored area of dynamics will remain over northern Lincoln
County into early evening before shifting southeast over northeast
Clark and northern Mohave Counties tonight. Its been snowing off/on
at Pioche with only wet roads being reported. Expecting highest
accumulations of 1-3 inches, locally higher amounts in the Wilson
Creek and White Rock Mountains in the northeast part of Lincoln
County east of Pioche. As for northern Mohave County tonight, again
generally 1-3 inches populated areas along Highway 389 in far
northern Mohave County. Some of the higher plateaus/mountains may
see 3-6 inches.

Precipitation will taper off quickly after daybreak Sunday with an
isolated light showers possible around Mt. Trumbull and Mt. Logan
through 10 am MST. Elsewhere, region will lie under a dry northwest
as high clouds increase from the west. Temperatures running about
6-10 degrees below normal tomorrow.

Flat, dirty ridge will encompass the Intermountain West Monday.
Early week warmup will commence as temperatures edge upward closer
to normal.

.LONG TERM...Tuesday through Saturday.

Active weather pattern will continue through the long term, though
details related to precipitation timing remain unclear.  The weak
ridge will linger into Tuesday before the flow turns more
southwesterly in advance of an approaching trough midweek. Despite
the ridging, periods of mid and high cloud cover are likely for the
early part of the week thanks to an active Pacific flow aimed at the
West Coast and the low amplitude nature of this ridge.

Bigger changes will begin to move in as early as Tuesday evening
with increasing precipitation chances spreading into the Sierra.
Origins of the moisture source for this midweek storm system are in
the tropical Pacific, so this storm will be quite warm, limiting
snow accumulations to the highest elevations above 7-8k feet.  Model
agreement remains unclear with the timing of the best precipitation
chances, with the GFS about 12 hours faster than the ECMWF. But
general consensus is for precipitation chances to increase Wednesday
for areas north and west of I-15, and  then spread to the entire
region Wednesday night into Thursday before shifting east Thursday
night.  With these trends in mind, boosted PoPs slightly for the
above mentioned time periods, but further tweaks and enhancements
can be expected as model agreement improves over the coming days.
Improving conditions are expected Friday as the weather system
departs to our east.

.AVIATION...For McCarran...Breezy south to southwest winds will
continue through the evening with gusts from 20-25 knots. Only a
small chance of a shower at the terminal overnight with better
chances in the Peach Spring and Mormon Mesa approach corridors. CIGS
could lower to 6k or 7k feet after midnight during the best chance
for showers.

For the rest of southern Nevada, northwest Arizona and southeast
California...Breezy to windy south to southwest winds will continue
across most areas this afternoon into the evening with wind gusts in
the 20-25 knot range. Scattered showers primarily east and north of
Las Vegas with isolated embedded thunderstorms possible this evening
across mainly Lincoln and northern Mohave Counties. CIGS will lower
generally in the 5k-8k feet range across the area but could
temporarily lower to under 5k feet in areas of rain or snow.

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


LONG TERM...Outler

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