Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Las Vegas Nevada
300 am PST Thursday Dec 25 2014
Synopsis...gusty north winds are expected across the region today
along with much cooler temperatures. A few rain and snow showers
will also be seen over portions of the southern Great Basin. Drier
conditions and lighter winds are expected Friday...but cooler
temperatures will remain through the upcoming weekend. Another
system is expected to drop into the region early next week bringing
another shot of cooler temperatures along with gusty winds.
Short term...today through Friday night.
Strong cold front currently sweeping through southern Nevada and
northwest Arizona with strong gusty northwest winds behind the
front. Widespread Wind Advisory level winds have been occurring
across the region and a few locations have even topped 60
miles per hour...although brief. Hires models and numerical guidance continue
to show gusty winds occurring through much of today before
diminishing this afternoon. Have elected to extend the current Wind
Advisory from 18z to 22z this afternoon thinking that winds will
remain in the advisory levels for a little longer than initially
forecast...especially for Esmeralda and central Nye counties where
the winds will be the strongest. Main band of precipitation is
currently moving through Lincoln County where a few sites have
registered up to 0.03 inches of precipitation so far. Precipitation
has also developed further south across portions of Clark County
where Las Vegas received a trace of rain. Most of this
precipitation is associated with the main frontal band and will
continue to track east this morning...although a few showers will
remain in the mountains. The current Winter Weather Advisory for
Lincoln County still looks good and have no plans of changing that.
Most of the precipitation will be out of the area Friday...but a few
lingering showers will still be possible across far eastern Lincoln
and far northern Mohave counties.
Overnight lows tonight will be a bit tricky because there could
still be enough wind overnight to keep temperatures from falling too
far. Its possible that portions of the lower Mojave deserts will
see freezing temperatures its more likely Saturday morning with
lighter winds and generally clear skies.
Long term...Saturday through Wednesday.
The 00z medium range operation models were in quite good agreement
with the synoptic pattern over the western states through the middle
of next week. They indicate a broad trough allowing a cold air mass
to dive out of western Canada into the Great Basin Sunday and Monday
then it spins up into a closed low over southern Nevada/Southern
California Tuesday and Wednesday. They bring the system farther west
than previous runs and there is now enough moisture indicated to
mention at least a slight chance of precipitation over southern
Nevada and northwest Arizona. This system is cold enough that snow
could make it down to most of the desert floors. However...it is too
early to specify details. There are still some differences in the
track of the system and how far west it may go...but the main story
will be a cold week in store going into the New Year with nighttime
temperatures near or below freezing for all but maybe the lower
Colorado River valley Tuesday and Wednesday.
Aviation...for McCarran...gusty northwest winds are expected much
of today with speeds ranging between 20-30 kts...although some gusts
up to 35 kts will be possible. Broken-overcast ceilings around 6-7k feet through
15z with clouds becoming scattered-broken 08-100k feet through the afternoon.
There will be some showers in the mountains this morning. Wind
speeds will gradually diminish during the afternoon with northwest
winds under 20 kts after 23z.
For the rest of southern Nevada...northwest Arizona...and southeast
California...gusty northwest winds across the region today with the
strongest winds over Esmeralda and central Nye counties with speeds
up to 40 kts. Remainder of the region will see winds between 25-35
kts. Rain and snow showers mainly over Lincoln and Mohave counties
with ceilings between 3-5k feet. Elsewhere scattered-bkn060-080 feet. Winds
are expected to diminish late afternoon with dissipating clouds.
Spotter activation is not expected at this time. However...spotters
are encouraged to report any significant weather conditions
according to Standard operating procedures.
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