Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 040946

Area Forecast Discussion
National Weather Service Reno NV
146 AM PST Mon Dec 4 2017


Strong and gusty east winds are expected across the ridges today
into Tuesday morning with choppy conditions expected on Lake
Tahoe. High pressure amplifies over the region this week bringing
inversions, very cold nights, light winds, and reduced air quality
for valleys.



Weak trough across the Sierra and Nevada paired with high pressure
intensifying along the west coast will establish a strong east-west
temperature gradient across the Sierra tonight into Tuesday. High
pressure will build across the entire west coast for Tuesday and
Wednesday with strengthening inversions, very chilly nights, and
reduced air quality for the valleys.

Today - Tuesday: Gusty east ridge winds will develop with the
strong east-west temperature gradient in place, peaking late
tonight. Ridge wind gusts between 60 to 80 mph will be possible
from Lake Tahoe southward to Mono county. These winds will likely
mix down to Lake Tahoe and create choppy conditions this afternoon
into Tuesday morning. Winds should begin to decrease by midday

Wednesday - Thursday: Ridge intensifies over California and Nevada
which will strengthen existing temperature inversions and contribute
to air quality concerns for the valleys. Very dry air along with the
inversions will result in very chilly temperatures through the week
with many locations in the teens and lower 20s and coldest valleys
into the single digits or below zero. Ensure vulnerable communities
as well as pets and livestock have shelter from the cold. -Edan

.LONG TERM...Thursday onward...

An anomalously strong ridge remains in place across the west and
doesn`t look to go anywhere through at least the first part of next
week despite a few weak waves trying to impact it. With cold air
trapped at the surface and a warm air mass aloft, inversions will
remain in place. Mixing heights may only reach 800-1200 feet AGL
below the inversion with reductions in air quality and hazy
conditions likely. While the air mass will be extremely dry under
the ridge, there may be enough lingering moisture trapped under
the inversion due to snowfall the weekend prior to allow freezing
fog to develop in fog prone valleys.

A gradual warming trend will continue for the end of the week and
into the weekend, with mountain valleys possibly seeing warmer
afternoon high temperatures than lower elevation valleys below the
inversion. While overnight lows will moderate slightly, all valleys
will remain seasonably chilly in the teens to mid 20s. Mountain tops
will be in the 20s and 30s for lows with the warmer air aloft.

Looking ahead, there is no signal for any significant storms
through at least the middle of December. -Dawn



Easterly winds are increasing across ridgelines and can be observed
surfacing along western Sierra slopes. Sustained northeast to east
winds of 45-55 kts with gusts of 60-75 kts across Sierra ridges will
cause turbulence and mountain wave activity along and downwind of
the Sierra through Tuesday morning. For valley locations, peak winds
are expected to be 10-20 kts.

The winds are likely to mitigate widespread fog development, however
patchy fog is possible through the Martis Valley, including KTRK,
the next several nights/early mornings. -Dawn


.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory from 1 PM this afternoon to 10 AM PST Tuesday

CA...Lake Wind Advisory from 1 PM this afternoon to 10 AM PST Tuesday



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