Scientific Forecaster Discussion
fxus65 kvef 270350
Area forecast discussion
National Weather Service Las Vegas Nevada
850 PM PDT sun Mar 26 2017
Synopsis...a vigorous low pressure system will then slide over the
Great Basin and Four Corners region Monday through early Tuesday
leading to strong winds along with some showers and slightly cooler
temperatures for our area. This will be followed by an even stronger
system Thursday into next weekend.
Update...its the calm tonight before the strong wind event on
Monday/Monday night, continuing at least down the Colorado River
valley on Tuesday. Current wind headline timing and placement looks
good with strongest wind expected across the western Mojave Desert.
Although once all 00z data arrives need to take a closer look at
potentially upgrading Esmeralda/central Nye to a warning as very
tight surface pressure gradient is forecast between Las Vegas and
Reno. No update this evening.
Aviation...for McCarran...southwest wind expected
overnight with northwest winds developing during the day Monday.
Speeds through late Monday afternoon should be between 6-12 knots
with occasional gusts over 15 knots. Stronger northwest winds
expected after 01z with gusts over 30 knots possible for much of the
For the rest of southern Nevada, northwest Arizona and southeast
California...increasingly strong west winds expected across the
western Mojave Desert near kdag and knxp by Monday morning. Wind
gusts of 40 - 50 knots will be possible from Monday morning through
Monday evening. Otherwise, breezy conditions out of the southwest or
northwest direction can be expected elsewhere, with a strong push of
north winds expected near kbih and across southern Nevada Monday
afternoon and evening where gusts over 35 knots will be possible. A
few showers are also possible east of a ktph-kigm line Monday
afternoon and evening.
Previous discussion...230 PM PDT sun Mar 26 2017
short term...through Wednesday night.
After a very tranquil Sunday, the weather will turn more active
tomorrow as a shortwave trough dives south towards Arizona through
Tuesday morning. The biggest impact we will face with this feature
will be strong winds, while a few showers and slightly cooler
temperatures are expected as well.
As far as the winds go, high resolution guidance as well as MOS
guidance suggest strongest winds Monday will be focused across the
western Mojave Desert near Barstow where wind gusts to 60 mph will
be possible. Pockets of blowing dust are likely as well and i've
posted a High Wind Warning for this area through Monday evening.
Strong west winds are likely further south impacting the morongo
basin and Yucca Valley as well but will be a notch weaker compared
to the winds near Barstow and will linger longer into the night, so
a Wind Advisory has been posted for that area through Tuesday
Meanwhile, a push of strong northwest winds are expected for most of
southern Nevada and across Inyo County starting midday (in
Esmeralda/northern Nye counties) and spreading southward to
encompass much of the region by Monday evening. Wind gusts with
this push may locally exceed 50 mph and after the initial push of
north winds during the evening...the strong winds will linger into
Tuesday morning. For the Las Vegas Valley, strongest winds will be
favored over the northern portion of the valley (centennial hills,
North Las Vegas, nellis) with somewhat weaker winds expected across
the southern half of the Metro. All in all, a gusty evening and
overnight are expected Monday into Monday night.
As far as precipitation GOES, best chances will be limited to
Lincoln and northern Mohave County where some showers and a few
thunderstorms are a good bet as the trough dives south. A few
showers may develop as far west as Las Vegas but probabilities are
fairly low. Any showers that do form are likely to enhance localized
Calmer weather is in store Tuesday afternoon and Wednesday after the
winds relax, with mostly sunny skies and seasonable temperatures.
North winds will linger near Laughlin through midweek however and
wind gusts over 30 mph can be expected each day.
Long term...Thursday through Sunday.
Models are in agreement that a strong upper low will move into the
Great Basin Thursday but the European model (ecmwf) continues to be a bit farther
southwest with the center of the low and therefore farther southwest
with precipitation development. I went with more/less a compromise
between the European model (ecmwf) and the GFS with precipitation chances Thursday
basically north of Las Vegas. As with monday's storm, the main
threat for any decent precipitation amounts once again will be over
Lincoln County. Elsewhere the main concern will be wind with strong
west to southwest winds possible across much of the Mohave desert
and strong northwest winds working into the southern Great Basin.
The upper low will move to somewhere near the Arizona/Utah border Thursday
night with precipitation chances mainly east of Las Vegas with the
best chances over eastern Lincoln and northern Mohave counties.
Strong northerly winds will likely spread down into most of the
forecast area. With the low near The Four Corners area Friday, most
of the area will be dry although there is still a chance of showers
over Lincoln County and portions of Mohave County. Gusty north winds
are likely to persist over much of the area with temperatures
roughly 10 degrees cooler than Thursday. The upper low is not
progged to move very quickly Friday night and Saturday with a few
showers possibly hanging on in eastern Mohave County. Temperatures
will rebound a little Saturday but northerly breezes will continue.
There is little agreement with the overall pattern for Sunday.
Ridging is indicated by the GFS while the European model (ecmwf) brings some
shortwave energy down in a persistent northerly flow with
precipitation clipping Lincoln and Mohave counties. The Canadian
model also indicates ridging with dry conditions. For now I kept the
forecast dry with slight warming.
Spotter information statement...reports of wind damage or low
visibility due to dust are encouraged. Otherwise...spotters are
encouraged to report any significant weather or impacts according to
Standard operating procedures.