Blowing Dust Advisory 1, NWS Reno, NV

Area Forecast Discussion
National Weather Service Reno NV
243 AM PST Tue Jan 19 2021

.SYNOPSIS...

Strong northeast winds will continue this morning in the Sierra
with lighter winds in the lower elevations. Winds will diminish
this afternoon and evening. Temperatures will cool closer to
seasonal averages today before warming as quiet weather returns
Wednesday and Thursday. The pattern shifts to a more active one
Friday through next week.

&&

.SHORT TERM...

Not much change to the going forecast this morning with Sierra
ridge gusts well over 100 mph this morning. In the lower
elevations, winds are gusting to 45 mph out of the northeast. We
still expect these winds to continue through the morning before
weakening this afternoon as the upper low moves south and away
from the region.

After today, short wave ridging will be present over the Sierra
and western Nevada with temperatures a few degrees above average.
Winds will also be light, but clouds will start to increase
Thursday as another upper low approaches from the north-northwest.
While there could be a few light snow showers with it near the
Oregon border Thursday night, most precipitation won't arrive
until Friday. X

.LONG TERM...Friday through the end of January...

No significant changes made to the long term forecast this morning,
besides for some tweaks here and there to the POP and QPF regarding
the storm system for Friday and Saturday. The main highlights in the
long term are that a wetter and colder pattern is expected to set up
over the west beginning Friday and possibly continue to close the
month. This means periods of breezy winds and snow across the region
along with colder (below average) temperatures are possible, if not
likely, at this time.

With the Pacific ridge of high pressure positioning itself just
north of Hawaii and amplifying into the Gulf of Alaska by early
Friday, this synoptic pattern opens the door for low pressure
systems (originating from western British Columbia) to migrate
southward, tracking along the east side of the ridge. A series of
storm systems looks likely at this time to take advantage of this
potential pattern set-up and impact much of the western United
States.

*Storm 1...Friday and Saturday:

Both deterministic and ensemble guidance are in good agreement with
a low pressure trough diving southward and generating impacts to the
Sierra and western Nevada region for early Friday into Saturday. As
the positively-tilted trough digs southward with its base hugging
the California coast, much colder air will be able to funnel in from
the north allowing snow levels to drop to all valley floors. Since
upper-level support is lacking over the Sierra and western Nevada,
this storm shouldn't be a big wind producer with most (at least 75%)
of the ECMWF ensemble members showing 20-25 mph gusts across western
Nevada/northeast California and the Sierra in the 30-40 mph range.
Of course the ridges will be a bit stronger, but nothing impressive
at this time. Peak winds look to take place on Friday ahead of the
trough's front becoming breezy, post-frontal thereafter.

With much colder air accompanying the trough as stated
previously, snow showers are possible down to all valley floors
during this time. Since winds look to be not as strong with this
system, there could be some leftover warmer air from earlier in
the weak out in portions of Pershing, Churchill, and Mineral
counties which could see a mix of rain and snow on Friday before
that warmer air mixes out once the cold front sweeps through by
early Saturday. Precipitation looks likely mainly with the frontal
passage on Friday, but chances could extend well into Saturday
all depending on the trough's progression. The GEFS and the
deterministic GFS this morning show show the trough digging a bit
farther south into southern California/western Arizona while as
the ECMWF tries to stall the center of the low just south of Mono
and Mineral counties. If the ECMWF scenario were to pan out, then
deformation snow bands could form across western Nevada (mainly
along and south of I-80) allowing more snowfall to take place
Friday night into Saturday. The GFS is similar, but farther south
into southern Nevada/western Arizona.

While there is still time to figure out the details regarding snow
amounts, here are the most recent snowfall probabilities from the
National Blend of Models (note that the NBM is favoring the GFS
outcome a tad more):

Susanville: 15% for >2" and 25% for >1"

South Lake Tahoe: 25% for >4" and 75% for >1"

Reno: 15% for >2" and 45% for >1"

Lovelock: 15% for >1"

Mammoth Lakes: 15% for >4" and 70% for >1"

If you didn't notice, the overall NBM trend has been down from
yesterday in regards to total snow amounts.

*Storm 2...Late Sunday into Tuesday:

Another, but wetter system remains on the table with confidence
increasing in another round of widespread snow chances across the
region. As of now, the good news for us forecasters regarding this
storm is that any precipitation that does take place will most
likely be in the form of snow as snow levels are forecast to be
below 4000 ft. None of this rain/snow line, pockets of warm air
shenanigans...hopefully. Snow amounts vary greatly at this point in
the game due to model discrepancy. Having said that, we feel
confident enough to say that snow and travel disruptions are
becoming more likely to start next week.

-LaGuardia

&&

.AVIATION...

Strong northeast winds continue over the Sierra with 100+ kt wind
gusts over the crest. Turbulence and LLWS will continue in the
Sierra valleys with it worst around Lake Tahoe (KTRK/KTVL).
Wind gusts at the terminals generally to 25 kts, but locally
stronger at KTVL at 40-45 kts. Expect the worst conditions to
continue through 18Z with gradual improvement thereafter.

Quiet VFR conditions Wed and Thur before another upper low drops
in Friday into Saturday with some MVFR CIGS/VIS possible in -SHSN.
Some runway accumulations are possible, but which locations to be
favored is unknown as the system is small. X

&&

.REV Watches/Warnings/Advisories...

NV...High Wind Warning until 7 PM PST this evening NVZ002.

CA...High Wind Warning until 7 PM PST this evening CAZ071>073.

&&

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE RENO NV
1015 AM PST TUE JAN 19 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0657 AM     NON-TSTM WND GST 2 S MAMMOTH MOUNTAIN    37.63N 119.03W
01/19/2021  M108 MPH         MONO               CA   MESONET

            MESONET STATION MTH03 1.7 S MAMMOTH MOUNTAIN
            (MAMMOTH).

0120 AM     NON-TSTM WND GST 1 ESE MOUNT ROSE SUMMIT 39.31N 119.88W
01/19/2021  M79 MPH          WASHOE             NV   MESONET

            MESONET STATION SLIDE 0.9 E MOUNT ROSE
            SUMMIT (DRI).

1014 PM     NON-TSTM WND GST 8 WSW WADSWORTH         39.59N 119.43W
01/18/2021  M75 MPH          WASHOE             NV   MESONET

            MESONET STATION DBYNV I-80 AND DERBY DAM.

0500 AM     NON-TSTM WND GST 3 SE DOLLAR POINT       39.16N 120.07W
01/19/2021  M47 MPH          PLACER             CA   MESONET

            MESONET STATION JPL04 3.1 SE DOLLAR POINT
            (JPLNASA).

1240 AM     NON-TSTM WND GST 1 E LOYALTON            39.68N 120.22W
01/19/2021  M45 MPH          SIERRA             CA   MESONET

            MESONET STATION LIB22 CEM41-GARAGE PIT RD.

1053 PM     NON-TSTM WND GST 3 N MEYERS              38.90N 120.00W
01/18/2021  M44 MPH          EL DORADO          CA   ASOS

            ASOS STATION KTVL SOUTH LAKE TAHOE AP.

0414 AM     NON-TSTM WND GST 2 NNE ZEPHYR COVE       39.02N 119.94W
01/19/2021  M42 MPH          DOUGLAS            NV   MESONET

            MESONET STATION SKYN2 SKYLAND.

1240 AM     NON-TSTM WND GST 5 SE TOMS PLACE         37.51N 118.64W
01/19/2021  M41 MPH          MONO               CA   MESONET

            MESONET STATION SE392 5.1 SE TOMS PLACE
            (SCE).

0850 AM     NON-TSTM WND GST 1 SSE SOUTH LAKE TAHOE  38.92N 119.97W
01/19/2021  M40 MPH          EL DORADO          CA   MESONET

            MESONET STATION LIB19 MEY3500-STPD OFFICE.

1050 PM     NON-TSTM WND GST 1 NNE HOLBROOK JUNCTION 38.75N 119.54W
01/18/2021  M40 MPH          DOUGLAS            NV   MESONET

            MESONET STATION NV020 NORTH TOPAZ LAKE.

0955 AM     NON-TSTM WND GST 11 SSW SAND MOUNTAIN    39.16N 118.48W
01/19/2021  M39 MPH          CHURCHILL          NV   MESONET

            MESONET STATION GHG44 GLENDALE-GRANDVIEW.

0740 AM     NON-TSTM WND GST 4 NW SPANISH SPRINGS    39.67N 119.77W
01/19/2021  M38 MPH          WASHOE             NV   MESONET

            MESONET STATION DESN2 DESERT SPRINGS.

1220 AM     NON-TSTM WND GST 1 WNW FLORISTON         39.40N 120.03W
01/19/2021  M37 MPH          NEVADA             CA   MESONET

            MESONET STATION LIB21 WSH201-FLORISTON.

0150 AM     NON-TSTM WND GST 4 S BECKWOURTH          39.76N 120.37W
01/19/2021  M36 MPH          PLUMAS             CA   MESONET

            MESONET STATION LIB10 4.2 S BECKWOURTH
            (LIBERTY).

0340 AM     NON-TSTM WND GST HEAVENLY VALLEY         38.97N 119.89W
01/19/2021  M35 MPH          DOUGLAS            NV   MESONET

            MESONET STATION NV027 SOUTH DAGGETT PASS.

&&