Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 270944
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
244 AM PDT Mon Mar 27 2017

.SYNOPSIS...

The ongoing storm will bring travel impacts to the this morning`s
commute but then quickly exit the Sierra and western Nevada by
this afternoon. Breezy northwest winds will create choppy lake
conditions, especially on Pyramid Lake. Another storm on Thursday
may bring additional rain and snow to the Sierra and western
Nevada.

&&

.SHORT TERM...
This current storm will continue to bring precipitation to the
Sierra and western Nevada through this morning. Snow will likely
impact the morning commute for locations above 6000 feet, with
mostly just wet roads below 6000 feet. Check road conditions
before you leave this morning as many locations as of 3AM have
chain controls. Even if the roads are "just wet" that will create
slick driving conditions, so leave extra time for your morning
commute today. The bulk of the precipitation will push through
before 5am this morning with only light residual showers expected
through mid morning.

Brisk and drier northwest flow behind the cold front today will
clear out much of the residual shower activity for the Sierra and
western Nevada. Northwest winds will also create choppy lake
conditions, particularly for Pyramid Lake.

Northeast to east flow on Tuesday along with shortwave ridging
will allow for a modest warm up for the region with temperatures
in the lower valleys in the mid 50s to low 60s and in the low 50s
for the Sierra. Wednesday temperatures will be noticeably warmer
as some lower valley locations may reach the high 60s. Tuesday
through Wednesday will also feature light winds and dry conditions
before another storm approaches the area. Remember when we said
it was starting to look warmer and drier for the end of March and
into early April? That may not pan out. -Edan


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

A few minor changes were made to the inherited forecast for the
Thursday time frame...mainly to adjust QPF...but also to raise low
temperatures a bit more Thursday morning over the southern CWA. Also
lowered high temperatures a little Friday.

Operational models continue to differ slightly in their timing and
placement of a vigorous upper low and associated surface front
dropping south-southeast across the Great Basin Thursday. The
leading edge of the precipitation starts to move into the northern
parts of the CWA Wednesday night...but the more widespread
precipitation develops Thursday.

The GFS is still farther east than the ECMWF with the track of the
upper low. The ECMWF also remains slightly faster dropping it south-
southeast. The ECMWF has been a bit more consistent...but has
virtually no support from the GEFS ensemble members. They
overwhelmingly support a track across northeast NV closer to the GFS
as opposed to the track through central NV the ECMWF depicts. With
differences remaining in the track forecast...the details remain a
bit up in the air. Confidence is increasing that Thursday will see
breezy winds early with daytime highs likely in the morning before
the cold front sweeps south-southeast. Snow levels fall through the
day. QPF is not very significant...but the convective nature of any
precipitation means isolated areas could see bursts of heavy rain or
snow. There is still enough forecast instability to support a slight
chance of thunderstorms in the eastern portion of the basin and
range Thursday afternoon. The track of the upper low will have a
larger affect on the western parts of the CWA. The GFS solution
would be a little drier west of Highway 95 while the ECMWF would be
wetter.

Behind the surface front and upper low...showers will linger over
far eastern sections of the CWA into Friday. A brisk north to
northwest flow develops behind the low. This will hold temperatures
down a bit for Friday so highs were lowered slightly. This could
also result in gusty lake winds for Pyramid.

Ridging develops by Saturday and persists into early Sunday. This
will lead to temperatures warming back above normal for the start of
April. Earlier forecast models were developing this ridge and
leaving it in place for a few days. Now the ECMWF is dropping
another short wave into the region with precipitation by Sunday
afternoon. The GFS is not as aggressive...but does have a trough
moving into the west coast by early Monday morning. For now we will
leave Sunday mainly dry and mild...but this could change with
subsequent forecasts.

The transition seasons...of which spring is one...can be notoriously
difficult for forecast models to handle beyond a few days. This is
the time of year when the extended forecast can see wide swings from
forecast to forecast. What we saw as a return to mild and dry
conditions for early April could now be transitioning to a period of
wet cool weather if the current model simulations are to be believed
beyond seven days. Keep that in mind when looking at any extended
forecast in the spring.

&&

.AVIATION...
Rain and snow showers will weaken and dissipate by this
afternoon, with the strongest periods of snow expected before
sunrise today. Still expecting brief MVFR conditions and mountain
top obscurations through the day. Brisk northwest to north winds
will develop behind the cold front today with afternoon and
evening wind gusts 25-30 kt, except a few stronger gusts up to 40
kt possible over southern portions of Mineral-Mono counties.

Tuesday and Wednesday will be dry with light winds, while another
system queues up for Thursday. Rain and snow showers with gusty
winds are expected with that next system, with a few thunderstorms
possible over west central NV. -Edan

&&

.REV Watches/Warnings/Advisories...
NV...Lake Wind Advisory from 11 AM to 8 PM PDT Monday for Pyramid
     Lake in NVZ004.

CA...None.
&&

$$

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



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