NWS Reno, NV wrote its last area forecast discussion before the first event at Jan 26, 1:19 PM PST, 10 hours 41 minutes earlier.
Area forecast discussion, Jan 26, 1:19 PM PST, 10 hours 41 minutes before
Area Forecast Discussion
National Weather Service Reno NV
119 PM PST Tue Jan 26 2021
.SYNOPSIS...
A major winter storm will bring very heavy snow and blizzard
conditions to the eastern Sierra tonight through Friday. Heavy
snow and local whiteout conditions are also expected for northeast
California and western Nevada. Quieter weather this weekend with
only some light snow in the Sierra before another significant
storm hits early next week.
&&
.SHORT TERM...
***MAJOR WINTER STORM FOR THE EASTERN SIERRA INTO EXTREME WESTERN
NEVADA***
Bottom line up front: Be where you need to be by sundown today
(midnight at the absolute latest)-you might be there for a couple
of days. Have a back-up plan for school/work/childcare/etc. Ground
travel could become impossible at times tonight through Thursday,
especially in the Sierra. This storm will be measured in feet for
the Sierra as well as portions of the western Nevada Sierra
Front.
A potent and long lasting winter storm will move in tonight with
moderate to heavy snow from the Sierra into some western Nevada
lower valleys. Heaviest snow tonight into Wednesday with a period
of thundersnow along the front, then somewhat less heavy snow
will continue into Thursday night. The heaviest snow will be in
the Sierra and adjacent lee side valleys with much less into
central Nevada with more wind there. The snow continues into
Thursday night for many areas before ending Friday morning.
Details to follow for each area: Eastern Sierra, Nevada Sierra
Front, Northeast California and West Central Nevada. Go to the
section for your area, or if you are a weather nerd like us, read
them all.
* EASTERN SIERRA: Snow will be very heavy tonight into Wednesday
afternoon with blizzard conditions for many areas. Snowfall
rates could reach 6"/hr briefly along the narrow cold frontal
rainband, but will be more consistently 2-3"/hr. Wind gusts 100+
mph over the crest with up to 50 mph in the valleys. Winds
aloft weaken Wednesday night into Thursday night with more
localized blizzard conditions, but the heavy snow will continue
as the front stalls and pivots overhead. Snowfall rates of
1-3"/hr are still likely for the latter half of the event. See
the Blizzard Warning for details on amounts, but as mentioned
above it will be measure in FEET. High confidence in very heavy
snow with a 60% chance of 3 feet or more for Truckee, South Lake
Tahoe, and Mammoth Lakes.
* NEVADA SIERRA FRONT: Heavy snow beginning after midnight tonight
and continuing through Wednesday morning with good agreement in
HREF ensemble. Snowfall rates up to 3"/hr possible. Localized
blizzard conditions tonight into Wednesday morning as well since
wind gusts could reach 50 mph at times. Then, as the front
pivots, moderate to heavy snow increases Wednesday night into
Thursday morning. There is also the possibility that the snow
doesn't stop in some areas at all. That is most likely to occur
in Carson and Douglas County from the HREF. Also, while the flow
does become more SSW and is normally less conducive to
spillover, the forcing also becomes quite intense Wednesday
night which should keep the snow going along the Sierra Front
into Thursday afternoon. Snowfall rates won't be as heavy,
closer to 1"/hr, heaviest in Douglas County which does better in
SSW flow.
We also looked at the potential for snow levels coming off the
valley floors and it looks unlikely. More likely is the snow could
become wet or briefly mix rain with little accumulation during
the afternoon/early evening. The most likely place this would
occur is in the Reno-Sparks area where HREF shows a better
possibility of a break. Anticipated snow totals in the warning for
Reno/Sparks may be slightly less if this occurs, but overall we
are still looking at a 70% probability of 12+" for Reno/Carson and
85% for Minden/Gardnerville.
* NORTHEAST CALIFORNIA (and northern Washoe County Nevada): Heavy
snow tonight into Wednesday morning with localized blizzard
conditions, but then it becomes more showery with a break
particularly northern Washoe County. As the front pivots back
north, snowfall will increase again Wednesday night into
Thursday, but not be as heavy then end Thursday night. Snowfall
up to a foot in the valleys with 18" possible along the 395
corridor in Lassen County. West of Highway 395 could see 2-4
feet of snow.
* WEST CENTRAL NEVADA: This will be much more of a wind event here
with occasional light snowfall. Wind gusts of 50-55 mph are
possible out here and the wind advisories look good. Any snow
amounts in the valleys along Highway 95 will be 3 to 4 inches or
less and it is more likely to mix with rain at times. Farther
west for Fernley and Silver Springs could see 6" or so. One area
where heavy snow is possible is in the mountains south of
Yerington and west of Hawthorne where around a foot of snow is
likely.
.LONG TERM...Friday onward...
Mesoscale bands with continued upper level forcing may keep snow
showers going through midday Friday. The Sierra is a safe bet for
several more inches, with higher resolution guidance and ensemble
data hinting at chances for snow continuing in western Nevada as
well. Even though the brunt of the major winter storm will be
through by Friday morning, the impacts could easily continue with
another messy morning commute. If an area ends up under one of
these nearly stationary bands for 6+ hours, we could see several
inches of snow Friday morning for localized areas of Western NV.
The upper low finally slides eastward by late in the day, with
things winding down. However, there is another fast-moving, weak
system is right on its heels for the weekend. This wave largely
fizzles out as it moves inland, but could bring another 3-6" of
snow in the Sierra, mainly from Tahoe north. Of course, after the
anticipated amounts this week, that will hardly seem like
anything. Even so, it doesn't take much to bring difficult travel
conditions.
Another winter storm is on tap for Monday-Tuesday next week. This
could potentially be another significant winter storm with heavy
snow possible in the Sierra. Atmospheric river detection probs are
increasing with a Pacific moisture feed into this system, yet we
remain on the cold side of the jet. There does appear to be good
spillover potential into Western Nevada with a cold front on
Tuesday. Some ensembles are putting another round of decent snow
down to valley floors, while others keep snow levels just off
valley floors, with lower valley rain and foothill snow. This
system is also likely to bring another round of gusty winds
region-wide early next week.
Beyond this, ensembles are hinting at drier conditions after
about February 4-5 as ridging starts to build over the Eastern
Pacific. However, with the ridge axis near 135W, it may still keep
the door open for colder system to come out of the north. Either
way, near to below normal temps are likely to continue into the
first week of February. -Dawn
&&
.AVIATION...
Flying conditions are going to rapidly deteriorate tonight and remain
poor through Thursday night, or possibly Friday, as a major winter
storm impacts the region. Expect widespread terrain obscuration and
long duration IFR/LIFR conditions. Winds will also be strong with
moderate/severe turbulence, mountain wave activity, and low level
wind shear expected.
For the Sierra terminals:
Snow begins 9 pm to midnight tonight and snowfall rates could
exceed 3" per hours for a short duration overnight. Snow will be
"lighter" during the day Wednesday with another intense wave
Wednesday night into Thursday. When all is said and done, 2-3 feet
of snow is likely to accumulate. We also could see periods of
thundersnow tonight and again tomorrow night. The heavy snow and
blowing winds is likely to create periods with near zero
visibility.
For western Nevada terminals:
Snow will push into the area between midnight and 3 am with gusty
southerly winds possible tonight, continuing once the snow begins.
The heaviest snowfall rates are likely to be overnight into the
early morning hours, tapering off somewhat midday, before another
round of heavy snow pushes in Wednesday night into Thursday. The
combination of wind and snow will yield very low visibility. Snow
totals for KRNO/KCXP could reach 10-16 inches (higher for KCXP),
with possibly 24+ inches for KMEV.
In northeast CA into far northern NV snow and wind impacts will be
similar to above. As you go farther east into Central NV, there
will be less snow, but conditions will still be dicey with low
ceilings/visibility and gusty winds. -Dawn
&&
.REV Watches/Warnings/Advisories...
NV...Wind Advisory from 4 AM to 10 PM PST Wednesday NVZ004.
Winter Weather Advisory from 4 AM to 10 PM PST Wednesday NVZ001.
Blizzard Warning from 10 PM this evening to 4 AM PST Friday
NVZ002.
Winter Storm Warning from 10 PM this evening to 4 PM PST
Thursday NVZ005.
Winter Storm Warning from 10 PM this evening to 4 PM PST
Thursday NVZ003.
CA...Blizzard Warning from 10 PM this evening to 4 AM PST Friday
CAZ072.
Winter Storm Warning from 7 PM this evening to 4 AM PST Friday
CAZ071.
Winter Storm Warning from 10 PM this evening to 4 PM PST
Thursday CAZ070.
Blizzard Warning from 10 PM this evening to 4 AM PST Friday
CAZ073.
&&
For more information from the National Weather Service visit...
http://weather.gov/reno