Area Forecast Discussion
Issued by NWS Reno, NV

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843
FXUS65 KREV 231035
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
235 AM PST Thu Feb 23 2017

.SYNOPSIS...

Periodic isolated to scattered snow showers will linger through
Friday along with well below average afternoon temperatures. Two
disturbances will move over northeast California and western
Nevada over the weekend, with the second one Sunday into Monday
having the best chance to bring significant snowfall.

&&

.SHORT TERM...

There is still potential for lake-enhanced snow south and
southeast of Pyramid Lake today. (Instability will be enhanced
over Pyramid Lake because of the relatively warmer waters.) A
lake-enhanced snow band could possibly create 2-3 inches of snow
especially if it develops this morning while surfaces are cooler.
Forecast confidence is low in this feature but it could create
dangerous and slick road conditions around Fernley and on I-80
west of Fernley.

Elsewhere today, a weak upper disturbance along with marginal
instability will be enough to create isolated to scattered
showers, with the best chances in the afternoon north of US-50.
Showers should taper off after sunset in western NV but may linger
until midnight in the Sierra and in the Tahoe Basin.
Accumulations on paved surfaces should be fairly minimal during
the daylight hours but after sunset there is a chance for roads
across the Sierra to become slick and dangerous again including
I-80, especially near the summit.

Latest model simulations are slightly slower with the next low-
pressure which drops south out of Oregon Friday night. It appears
most of the energy will track along the coast which means it
wouldn`t be a heavy snow producer for the Sierra or western NV.
Still, showers look to be numerous across the area and thus there
will be another threat for winter travel impacts Friday night
through Saturday night. JCM

.LONG TERM...Sunday through Wednesday...

Medium range model guidance is continuing the trend started
yesterday of bringing the upper level trough southeast across the
region Sunday and Monday much farther inland and never fully
developing a closed low.

These changes to the operational model guidance...largely supported
by the most recent GEFS ensemble member runs as well...leans toward
a colder solution with less access to the deep moisture tap that is
now pointed more toward southern California. This means significant
changes going forward with regard to QPF.

We did not really alter pops too much as we could see quite a bit of
coverage Sunday night into Monday morning with the wave...but total
QPF was reduced quite a bit. This means less snow cover for the
Sierra...but maybe not as much of a reduction from the previous
forecast as one might think for the lower valleys east of the
Sierra. The cold nature of the system supports high snow ratios so
even with lower total liquid precipitation amounts we could still
see several inches of snow in the western Nevada and northeast
California valleys and an inch or two in the basin and range. That
could make the Monday morning commute interesting. Of course...the
way this system is evolving...the bulk of the energy could still go
into northeast Nevada and our area may get even less precipitation.
We will see how this evolves over the next few days.

Showers linger into early Tuesday then a ridge starts to develop.
That signals drier weather by Wednesday...but temperatures should
stay below normal as we get into low to mid level north to northeast
flow.

&&

.AVIATION...

VFR conditions expected overall today but with increasing chances
for showers through the daylight hours capable of creating brief
vsby below 2 SM and cig blo 020 AGL conditions. Up to a few
inches of snow accumulation on runways is also possible during
heavier showers. Showers should taper off after sunset in western
NV but could linger through midnight in the Sierra including at
KTVL and KTRK.

After midnight a dry period is expected for the rest of tonight
through Friday morning before the next round of showers develops
Friday evening into Friday night. A stronger storm is expected to
arrive late Saturday night into Sunday. 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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