Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 212138
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
238 PM PDT Fri Apr 21 2017

.SYNOPSIS...

High pressure overhead into Saturday will bring drier and much
warmer afternoon conditions. A couple of weak systems will brush by
to the north Saturday and then Sunday with increasing winds and
periods of clouds; light shower possible towards the Oregon border.
Additional systems will bring breezy conditions with periods of
more consistent precipitation next week. Temperatures will ease
down to near or slightly below average next week.

&&

.SHORT TERM...

A Flood Advisory has been issued for the Truckee River from Lake
Tahoe to Squaw Creek. This was necessary since the regulated flow
rate was increased to 1600 cfs to account for expected snowmelt
from this past season`s near-record snowpack. Impacts from these
rates have typically included minor flooding over the bike path
next to Highway 89 and other low-lying areas. However, this is
the highest flow on this section of the Truckee River since 2006.
If any changes to, or around, the channel have occurred since
2006, there may be unanticipated impacts. This will also result in
very powerful, fast, and cold water that will be hazardous to any
that venture into or near the river.

Otherwise, very few changes were necessary to the existing
forecast which continues to verify well. Models remain mostly
consistent with previous runs. High pressure and warm temperatures
are still on tap into this weekend. Slightly breezy winds can be
expected Saturday through Monday as weak waves transit through
Oregon. Gusts will generally be up to 30 mph each afternoon.

Ridging rapidly flattens Saturday afternoon with mainly zonal flow
developing from the eastern Pacific through the western United
States. Very low chances of mainly rain showers will be possible
towards the Oregon border with each passing wave through Sunday
evening. Then chances increase into Monday as a more consolidated
system moves into the Pacific Northwest. However, precipitation
totals will be meager since the moisture core is more directed
into Oregon and southern Washington State, and since forcing
mechanisms will be lifting northward. This flow pattern favors
higher snow levels and will only drop briefly to around
7000-7500ft early Monday.

Expect temperatures to begin trending cooler Monday, as well,
while the pressure gradient tightens increasing area winds. Ridges
will become gusty with mechanical turbulence likely for aviation.
Boyd

.LONG TERM...Tuesday and beyond...

For Tuesday-Wednesday, cool and breezy conditions are expected as
Pacific moisture spreads inland. While a portion of the moisture
feed is directed into the northern Sierra and western NV, the best
forcing remains well to the north, resulting in widespread cloud
coverage but only light showery precipitation. The better precip
chances are anticipated for eastern CA from Tahoe northward, and
western NV north and east of Lovelock-Gerlach. Snow levels through
Tuesday night should remain relatively high in the Sierra, generally
between 7500-8000 feet, then possibly drop to near 7000 feet by
Wednesday morning as precip winds down. Farther north from Lassen
County to the Oregon border, snow levels are more uncertain as a
more notable push of cooler air could accompany the moisture. While
prevailing snow levels look to remain between 6500-7000 feet for
Tuesday, they may drop to near 5500 feet by early Wednesday.

For the Reno-Carson vicinity and southward to Mineral-Mono counties,
gusty winds are more likely to be the primary effect of this weather
pattern, with only sparse amounts of rain or high elevation snow due
to the lack of forcing or instability.

Later next week, the overall trend favors the storm track shifting
farther north as high pressure ridge edges closer to the CA coast.
Another shortwave may brush across far northern CA on Thursday but
overall the chance for precip will diminish, with Friday looking
generally dry. Winds will also slowly decrease toward the end of
next week, with temperatures possibly warming a few degrees by
Friday.

Looking ahead to next weekend, there is some agreement for mainly
dry and warmer conditions as a ridge builds into CA-NV. However,
this ridge is relatively flat with additional shortwave energy
reaching the west coast by early May, so any warmup will likely be
short lived. MJD

&&

.AVIATION...

VFR conditions are expected this weekend with light winds thru
Saturday morning. Surface winds increase Saturday afternoon with
peak gusts up to 25 kt. Similar wind speeds are expected Sunday
afternoon. Sierra ridge gusts increase to near 65 kt, leading to
areas of turbulence near the Sierra from late Saturday thru the rest
of the weekend.

For much of next week, gusty winds will continue with periods of
showers mainly affecting the Tahoe terminals, northeast CA and
portions of northwest NV. MJD

&&

.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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