Area Forecast Discussion
Issued by NWS Reno, NV

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000
FXUS65 KREV 261015
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
315 AM PDT Mon Oct 26 2020

.SYNOPSIS...

Strong winds into Tuesday over and west of the Sierra crest with
breezy conditions elsewhere in the Sierra and for portions of
northeast California will cause continued fire weather concern in
those areas. Chilly temperatures again today will be followed by
much milder temperatures from midweek into next weekend. No rain
or snow is expected through at least next weekend.

&&

.DISCUSSION...

No significant change to the forecast this morning.

The long-advertised hard freeze for all areas is on track this
morning with even the warmest spots in the urbanized Reno-Sparks
area down to 29-31 so far this morning. Most valleys are currently
running in the mid-teens to mid 20s with some mixing holding even
the usually colder Sierra valleys up somewhat despite very dry air
(dewpoints mostly between -5 and 5).

Wind-wise, the real show is along and west of the Sierra crest
where earlier gusts reached between 95 and 119 mph at the crest
and 136 mph at Kirkwood (west slopes of the Sierra) as the pressure
gradient between Reno and Sacramento maxed out at over 10 mb. Away
from the tight pressure and thermal gradient packing along the
Sierra crest into the valleys of northeast CA and western NV,
winds are mostly less than 10 mph with gusts less than ~20 mph.
Stronger winds are on Lake Tahoe, on the west slopes of the
Carson Range, and in the Chalfant Valley (colder air spilling
downhill towards Bishop) where winds are gusting between 25-40
mph. Winds in these areas and over the Sierra crest are expected
to remain elevated into Tuesday. Therefore, expect hazardous boating
conditions on Lake Tahoe where a lake wind advisory continues
into Tuesday.

Temperature-wise, well below average high temperatures today will
modify back to a bit above average by Wednesday/Thursday as strong
high pressure builds overhead. With the initial cold punch early
this week, lows will also remain well below average through tonight...
but will modify substantially Tuesday and Wednesday nights.
Temperatures look to remain fairly steady-state from mid-week
through early next week under persistent high pressure.

Precipitation chances remain dismal through early next week. A
weak trough is projected to reach the West Coast by Friday and
may boost winds and cloud cover a bit. Unfortunately, this system
is expected to skirt by well to the north for little chance of
rain in northeast CA and western NV. -Snyder

&&

.AVIATION...

VFR conditions will continue through the week. This morning, minor
reductions to visibility are possible, mainly south of HWY 50, due
to blowing dust. Gusty north to east winds continue through the
tonight with periods of low level wind shear possible around the
Tahoe Basin. Mountain wave turbulence is likely to be moderate to
severe along and west of the Sierra Crest today due to the strong
jet stream overhead. Winds along the Sierra Crest are peaking out
this morning around 90kts. Expect those strong winds along the
Sierra Crest to continue through tonight and into Tuesday morning
before calming down. -Hoon

&&

.FIRE WEATHER...

* Red Flag Warnings remain in effect for the Tahoe Basin north to
  western Lassen County through noon Tuesday. A Red Flag Warning is
  also in effect for southern Mono County through Tuesday morning.

The extremely dry airmass is working into the region behind the
strong cold front that pushed through yesterday. Wind gusts along
the Sierra Crest of over 100 mph are occurring early this morning,
with the western slopes of the Sierra seeing the brunt of the high
winds. Besides the Sierra Crest, the rest of the Tahoe Basin and
northeastern Sierra, winds are gusty, but only gusting to around 30
mph as of early Monday morning. Valley winds will increase through
the morning hours, with relative humidity dropping to around 10-20%
this afternoon. Knox RAWS near Incline Village is already at 9%
with a dewpoint of -26F.

Yesterday, the Red Flag Warnings were extended into Tuesday, due to
models showing persistent winds continuing through Tuesday morning.
Winds won`t be as strong tonight as they are this morning, although
gusts up to 30-40 mph in wind prone areas and Sierra ridge winds up
to 70 mph will be likely. Poor overnight recovery is expected once
again tonight as the extremely dry airmass remains in place.

One other thing, it will be cold despite the very low humidity, and
the wind chill will be quite low in many of these areas tonight and
again Monday night. A quiet pattern does return for the second
half of the week. -Hoon

&&

.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory until noon PDT Tuesday for Lake Tahoe in
     NVZ002.

CA...Red Flag Warning until noon PDT Tuesday CAZ271-272.

     Red Flag Warning until 5 AM PDT Tuesday CAZ274.

     Lake Wind Advisory until noon PDT Tuesday for Lake Tahoe in
     CAZ072.

&&

$$

For more information from the National Weather Service visit...
http://weather.gov/reno


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