Area Forecast Discussion
Issued by NWS Reno, NV

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849
FXUS65 KREV 182136
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
236 PM PDT Tue Apr 18 2017

.SYNOPSIS...

Showers diminish this evening with a brief break in the weather
Wednesday afternoon. After a final weak system Wednesday night and
Thursday, a drier trend with a significant warm up is expected
heading into the weekend.

&&

.SHORT TERM...

Shower activity today has continued to shift south with mountain
snow and valley rain continuing south of Highway 50 this afternoon.
In Mono County where snow showers are continuing, the snow level
is hovering around 8500 feet. Showers should taper off completely
by late evening with a break in precipitation until Wednesday
night.

The final weather system of the week will brush by the area
Wednesday night into Thursday. Precipitation will be light as this
system moves quickly through the region with only around 0.2-0.3
inch along the Sierra crest from Tahoe northward. This system
does entrain some colder air than the previous system and since it
moves through overnight, snow may be able to accumulate down to
around 5500 feet around Truckee/Tahoe and around 4500 feet in NE
California. Snow accumulations will be light with around 1-3
inches of snow possible. Snow should melt off road surfaces
quickly during the day, but some snow covered roads should be
expected Thursday morning in the mountains.

A few areas of freezing fog will be possible tonight in fog prone
Sierra valleys as clearing skies allow temperatures to drop.
Winds will pick up Wednesday as the system moves in with gusts up
to 30-35 mph possible in the afternoon, especially in northwest
Nevada where temperature gradients will be stronger. 700 mb winds
increase briefly to 40+ knots Wednesday afternoon with ridgetop
winds potentially gusting to 75 mph. Temperatures will remain
below average Thursday before a quick warmup begins for the
weekend. -Zach

.LONG TERM...Friday and beyond...

Dry conditions with areas of cirrus are expected Friday and
Saturday as high pressure ridge builds across CA/NV on Friday, then
shifts to the east Saturday as another trough approaches the Pacific
Northwest. This will allow a decent warming trend with highs
around 70 degrees in some of the warmer valleys Friday, then
rising well into the 70s Saturday. For the Sierra valleys/Tahoe
basin, highs in the lower-mid 60s are expected both days. Light
winds Friday will become breezy Saturday afternoon (projected gusts
30-35 mph) ahead of the next trough, with this improved mixing
producing the additional warmup for lower elevations.

On Sunday, the trough passage across the Pacific Northwest will
bring a slight cooling with moderate breezes and possibly a few very
light showers near the Oregon border, but overall impacts on most
outdoor activities will be quite low.

For early next week, another trough is projected to quickly reach
the west coast Monday, then move inland to the Great Basin on
Tuesday. This is a faster progression than previous guidance, with
latest projections bringing increased clouds and winds by Monday
afternoon, and a chance for light precip to northeast CA-far
northwest NV.

The better chance for showers is indicated for Monday night and
Tuesday. Some cooling will occur as this low moves through, but
at this time the prevailing snow level still looks to range from
7000-8000 feet for the majority of this event. While current precip
projections are not very impressive, they have trended a bit wetter
compared to previous days.

Later next week, another trough within northwest flow aloft may
affect the area. However, there is more disagreement among the
medium range guidance as to whether a ridge near the west coast
builds inland or remains offshore. If the inland ridge scenario
occurs, we could see a decent warmup toward the end of next week,
leading to increased snowmelt runoff into area rivers and creeks.
MJD

&&

.AVIATION...

Lingering showers may produce brief MVFR cigs and mountain top
obscurations near KTVL-KMMH through the rest of this afternoon with
most activity diminishing by 01Z. Additional showers in west
central NV mainly east of US-95 should diminish after 00Z. Clearing
skies will then follow, leading to areas of FZFG with IFR/LIFR
conds around KTRK which could form before 06Z and persist through
16Z. Patchy FZFG is also possible around KTVL tonight, otherwise
VFR conds will prevail across the region thru Wednesday. The next
trough passage Wednesday night into Thursday morning will bring a
short period of rain and snow to eastern CA from the Tahoe basin
northward, and lighter showers across western NV mainly north of
I-80. Light slushy accumulations are possible around KTVL/KTRK
early Thursday morning along with MVFR and brief IFR CIGS/VSBY.

Surface winds will be fairly modest through early Wednesday, then
increase during the afternoon and evening, with gusts 25-30 KT
for the main terminals. Sierra ridge winds are expected to increase
Wednesday, with peak gusts 60-70 KT by Wednesday night leading
to increased turbulence and possible mountain wave activity. 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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