Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 121214
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
514 AM PDT Thu Oct 12 2017

.UPDATE...

Update to discuss smoke potential (no forecast update):

The potential for another significant influx of smoke today from
northern California fires is low based on the latest HRRR and NAM
simulations. Flow aloft at the fire sources is projected to be
north to northwest for today per the 06Z NAM...and the HRRR shows
all smoke/haze well west of the crest. Still, current air quality
reading remain degraded in the Tahoe area and less so in the Mono
Lake Basin and Mammoth area...and residual particulates could
keep air quality degraded this morning in the Sierra. Mixing
should be sufficient this afternoon to allow the airmass to dilute/mix
out the particulates enough for improved air quality. -Snyder

&&

.SYNOPSIS...

Below average temperatures are on tap through Saturday as a trough
moves over the West. Much stronger easterly winds are likely at  the
Sierra crest Friday night and Saturday as more intense surface high
pressure builds into the Great Basin. Warmer temperatures and dry
conditions are expected next week.


&&

.PREVIOUS DISCUSSION... /Issued 322 AM PDT Thu Oct 12 2017/

SHORT TERM...

Modest surface high pressure will remain over northeast California
and western Nevada today, bringing generally light winds (below 10
mph) for valleys and modest north to east winds (~10-20 mph) in the
high Sierra. Temperatures will top out 10-15 degrees below average
for this afternoon.

A shortwave will dive through the Pacific Northwest and into extreme
northern Nevada Friday and Friday night, bringing a chance of light
showers north of Susanville and Gerlach with snow levels falling
to around 5000-5500 feet across far northern Washoe County.
Precipitation amounts will be very little as the main upper forcing
remains well north and east of the region; therefore, any snow
accumulations north of Gerlach Friday night are expected to remain
~1/2" or less.

Elsewhere, the shortwave will push a dry cold front through that
will bring north-northeast winds into the forecast for Friday night
into Saturday morning as strong surface high pressure builds into
the Great Basin. This will bring a very tight temperature/pressure
gradient to the Sierra, with easterly winds blowing 60+ mph
(possible to 80 mph) over the immediate high Sierra crest.
-Snyder/Hoon

LONG TERM...Sunday through next week...

No significant changes were made to the long term forecast because
latest computer guidance is still showing a ridge over California
and the Great Basin Sunday-Monday and then the next dry cold front
arriving Tuesday. With high pressure aloft Sunday-Monday, clear
skies, light winds, cold mornings, and near or above average
afternoon temperatures are expected.

On Tuesday another dry cold front arrives, bringing a cool down and
breezy southwest winds with peak gusts 20-35 mph expected. Chances
for precipitation Tuesday are less than 10 percent. On Wednesday
there could be a few light showers north of Susanville-Gerlach but
the chances for any wetting precipitation look to be low.

Increasing westerly wind speeds are likely Wednesday-Thursday and
possibly through the rest of next week as a strong upper jet shifts
south over northern CA/NV. Computer simulations differ on the
strength of a trough dropping south out of the Pacific Northwest,
making it uncertain when and where the strongest winds may occur.
Nonetheless, Wed-Fri next week is a period to keep an eye on for
possible strong winds along with dry conditions. JCM

AVIATION...

Expect VFR conditions today with breezy westerly surface winds
this afternoon. Stronger west to northwest winds will develop
Friday afternoon with peak gusts 25-35 kts at Sierra Terminals and
15-30 kts at western NV terminals. Surface winds will trend towards
north to east Friday night with strong easterly winds at the Sierra
Crest level in the 50-75 kt range. JCM

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$

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



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