Area Forecast Discussion
Issued by NWS Reno, NV

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637
FXUS65 KREV 222138
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
238 PM PDT Wed Mar 22 2017

.SYNOPSIS...

Showers and isolated thunderstorms will diminish this evening with
dry conditions expected Thursday. Another storm system is likely
Friday into Saturday, with another possible early next week.
Neither storm looks very strong, but could produce some travel
impacts near the Sierra. Temperatures will remain slightly below
average through next Monday, then begin warming by midweek.

&&

.SHORT TERM...

The area of snow that produced some accumulations and travel
delays over I-80 west of Truckee this morning has weakened, with
mostly wet roads currently indicated on area web cameras. As
these showers diminish, the more favorable area for convection
this afternoon and early evening shifts to west central NV
southward to Mineral-Lyon-Mono counties. So far the cells have
not produced very much lightning, but with a little more heating
and slightly unstable conditions, a few thunderstorms will be
possible until around sunset. Additional light showers are
projected to develop and move across northeast CA-northwest NV and
into parts of the Tahoe basin this afternoon-early evening, with
a low potential for thunder. Precipitation amounts will be sparse
and generally less than 0.10 inch, while snow in the Sierra
(mainly in Mono County) will be limited to a couple inches. Little
or no additional precipitation is expected overnight into
Thursday as shortwave ridge moves across the region.

The next storm system is on track to reach the west coast by
Friday. This trough is expected to split as it moves onshore,
with the southern portion of the split tapping some moisture as it
moves rather quickly south across the Sierra during the daytime
and evening hours. With the bulk of the precip occurring during
the daytime, overall snow accumulations will be limited especially
in areas below 7000 feet. We are currently projecting a narrow
swath of 4-10" near the Sierra crest west of Tahoe, then dropping
off to 3-6" for western Mono County and higher elevations of
western Lassen/central Plumas counties, and maybe a slushy inch
or two in the Tahoe basin.

Compared to the previous storm systems this week, less instability
is expected east of the Sierra, which will limit the amount of
moisture spilling into far western NV. With shadowing more likely
around Reno-Carson City, the potential for gusty winds will
increase, with gusts 40-50 mph possible Friday afternoon and early
evening while Sierra ridge gusts could approach 100 mph. Farther
east into the Basin and Range, more upward motion is indicated on
the latest guidance, leading to a better chance for some rain
mainly from US-95 eastward. Even in these areas, rainfall amounts
are unlikely to exceed 0.25 inch.

For Friday night and Saturday, a weak secondary trough will keep
the possibility of light rain and showers going, with little or no
additional accumulations. Snow levels will generally range from
5500-6000 feet from US-50 northward, and 6000-7000 feet south of
US-50. High temperatures Saturday will edge downward a few
degrees, mainly in the 50s for lower elevations and 40s near the
Sierra. MJD

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

The next shortwave trough tracks across northern California Sunday
afternoon with the main push of moisture moving through the Sierra
and western Nevada Sunday night and Monday. Model agreement on the
trough`s arrival is good but differ on its departure. The GFS
recently develops a cut-off low over central Nevada on Monday while
the ECMWF quickly exits it with a more progressive solution. Do
think a cut-off solution is reasonable and will leave low end
precipitation chances in the forecast, but confidence is low end
with ensemble spread being quite large. Nonetheless, those with
travel plans should keep an eye on the forecast as accumulating
snowfall will be possible across the northern Sierra mainly above
6,000-6,500 feet Sunday evening into Monday morning.

Thereafter, the large scale pattern takes on a broad northwest flow
with the possibility of a few weaker embedded shortwave troughs
dropping through northern California and Nevada through the mid-
point of next week. Quite a bit of differences exist among
deterministic guidance in regards to precipitation, but overall
will look for a period of near seasonable temperatures with
periods of increased cloudiness. Fuentes

&&

.AVIATION...

-SHSN for KTRK and KTVL will diminish through late afternoon as an
upper level trough slides eastward. Best period of brief MVFR
conditions expected now through 00Z with most convection ending
after 03z. Areas east of KLOL and KNFL into central and eastern
Nevada will see convective activity through the evening as the
trough moves eastward.

VFR conditions and light breezes will prevail on Thursday before the
next storm arrives. Winds and turbulence will increase across the
Sierra ridgetops Thursday evening with peak winds expected by
mid afternoon on Friday. Surface wind gusts at the terminals
could reach 40-45 knots. -SHRASN possible for Sierra terminals
Friday afternoon/evening but with snow levels around 6,500 feet
accumulations may be limited on the runways. -SHRA and brief
periods of MVFR conditions possible for KRNO/KCXP on Friday.
Fuentes

&&

.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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