Area Forecast Discussion
Issued by NWS Reno, NV
FXUS65 KREV 021006
Area Forecast Discussion
National Weather Service Reno NV
306 AM PDT MON MAY 2 2016
Warmer temperatures are expected today with a slight chance for
showers and a few thunderstorms this afternoon. Thunderstorm
chances increase Tuesday and Wednesday with a few strong storms
possible by Wednesday. More widespread rain and high elevation
snow, with possible thunderstorms Thursday may continue into next
weekend as low pressure moves slowly across the region.
Several days of active weather remain probable across the eastern
Sierra and western Nevada as a large low pressure system slowly
approaches the California coast by midweek. A gradual warming
trend is expected for the next couple of days with a few valleys
possibly reaching 80 degrees Tuesday, before some cooling arrives
by Wednesday especially west of US-95.
Today appears to be the least active weather day for the upcoming
week. A weak shortwave brushing across northern CA will lead to
some shower and isolated thunderstorm activity mainly across
northeast CA and near the Sierra this afternoon and early
evening. Most of these cells will move to the north or northwest.
Eastward progression of convection will be limited as a layer of
warmer air aloft should cap much of the activity across western
NV, although some brief late day showers can`t be ruled out.
For Tuesday and Wednesday, a large low pressure over the eastern
Pacific moves slowly east, reaching the California coast by
Wednesday. The increased upper level divergence ahead of this
low, along with an influx of moisture will bring increased chances
for showers and thunderstorms across the region. For Tuesday, the
better shower and thunderstorm potential favors northeast CA, the
northern Sierra, and far western Nevada with some activity
continuing overnight. On Wednesday, higher precip chances will
spread across much of western Nevada as well.
Wednesday could be interesting as upper level jet streak rotates
around the low with the favorable left exit region possibly
providing enhanced lift over parts of eastern CA and western NV.
Some uncertainty remains with the eventual location of this
enhanced lift, but areas between US-395 and US-95 could be
targeted for more organized and stronger storms with potential for
heavy rainfall, if sufficient instability is present. A limiting
factor would be if instability is reduced due to widespread cloud
cover, then the strength of the convection would be somewhat
inhibited due to the increased wind shear aloft. In this less
unstable scenario, areas of light to moderate rain may still occur
with more isolated thunder. We will continue to monitor guidance
trends as slight changes in timing and location of the upper jet
could bring either scenario Wednesday afternoon-evening. MJD/Dawn
.LONG TERM...Thursday through Sunday...
Not too much change this morning as a cool and wet pattern is on tap
for the end of the week. Model simulations continue to show lower
than average spread in track for an upper low that is cut off from
the main westerlies, taking it slowly eastward across srn CA/srn NV
and to AZ/UT during this period. Model QPF continues to be quite
impressive Thu-Sat with model averages indicating 0.50-1.00"
across western NV and 1.00-2.00" along the eastern Sierra. While
it is still too early to determine where heavier bands of showers
will develop, locally heavy rain could result in some rises of
small creeks and streams. Snow levels will generally run between
7000-8000 feet although they could dip a bit lower in heavier
bands of showers. So impacts from snow accumulations should remain
confined to the highest passes and mainly at night. In addition to
the rain and snow, thunderstorms will be possible each day with
lightning and abundant amounts of small hail possible.
By Sunday, the effects of the upper low itself will move out of
the region. However, abundant moisture and warmer surface
temperatures will keep showers and thunderstorms going with model
soundings indicating plenty of CAPE for a few strong slow moving
storms. After highs in the 50s and 60s Thu-Sat, temperatures will
warm back to 60s and 70s by early next week. Hohmann
Scattered showers and isolated thunderstorms will stay confined
mainly to the Sierra crest this afternoon/early evening although a
stray shower could drift to the Hwy 395 corridor. So KTVL/KTRK will
see the best chance of a shower/storm, probabilities at 30%/10%
respectively. Otherwise, light winds and VFR through 18z Tue.
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