Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 152126

Area Forecast Discussion
National Weather Service Reno NV
226 PM PDT Mon May 15 2017


Slow moving low pressure will bring a chance for showers and a
few thunderstorms today, mainly over Mono, Mineral and Southern
Lyon counties. Another area of low pressure will bring gusty winds
Tuesday and Tuesday night with a chance for light rain and snow.
Drier conditions then return by midweek. Temperatures will remain
below average through Wednesday, followed by a warming trend.



An upper low is moving eastward over the Mohave Desert this afternoon.
The low`s deformation axis is extending through central NV southwest
to near Bishop. This axis and daytime heating are the focus for
showers and thunderstorms, mainly south of Highway 50, this afternoon.
Convective activity should wane quickly around sunset with loss
of heating and with the deformation axis exiting into southern and
eastern NV.

Tonight, clouds will be on the increase late for northeast CA and
western NV as the next upper disturbance (currently near British
Columbia coast) moves to the Washington coast. Tuesday morning, a
brief period of warm air advection (WAA) is indicated in simulations.
With the stabilization effect of the WAA, significant downslope
drying in the lee of the Sierra is not expected so at least a brief
period of light rain and higher elevation light snow is likely for
much of the region near and north of Highway 50.

Late Tuesday afternoon and Tuesday evening, the upper low will push
into eastern Oregon and drive a strong cold front into the region.
This will bring breezy conditions with gusts 35-45 mph for many
areas, and wind-prone/local gusts to around 50 mph or so. As far
as precipitation with the front, the issue for precipitation
intensity and coverage will be that the main deep forcing will be
near and north of the Nevada-Oregon-Idaho border. For the northern
Sierra, orographic enhancement near FROPA should be enough to
bring light valley rain and pass-level snow there, with very light
accumulations possible in the high Sierra. If precipitation lingers
to near or after sunset, a light and slushy road accumulation is
possible over Tahoe area passes.

Out in the lee of the Sierra over far western NV, precipitation
amounts are likely to fall off rapidly as moisture shallows with
the lack of deep forcing and drying effects downwind of the Carson
Range. Farther out in the Basin and Range, less disruption from
lee of the Sierra drying should allow for higher precipitation
amounts (although still relatively light with the fast frontal

Wednesday and Thursday, an upper ridge will slowly build overhead.
With a chilly start Wednesday morning and northerly flow aloft, highs
Wednesday will remain below average. On Thursday, temperatures will
begin a moderating trend with above average temperatures by the
weekend. Snyder

.LONG TERM...Friday through Monday...

Going into Friday, the ridge widens over the Southwest U.S. and
then starts to become very amplified with the axis remaining offshore
for the weekend. With the ridge axis remaining generally offshore
a few waves could dig into the backside of the shallow trough over
the Rockies. This would keep temperatures from reaching 10 degrees
or more above average until the ridge moves more directly overhead.

A nice warming trend will take hold for the end of the week and into
the weekend. By the weekend temperatures should be in the low 80`s
for western Nevada and low 70`s in the Sierra, about 5-8 degrees
above average. By Sunday, and into Monday it`s possible we could
have enough instability and forcing from daytime heating, or a
passing shortwave, for afternoon thunderstorms to start to develop.

Early indications for the beginning of next week are for continued
warm temperatures and the potential for afternoon thunderstorms.
It`s possible temperatures could reach 10+ degrees above average,
but at this point it doesn`t look like it would be for an extended
period of time. -Zach



Low pressure in southern CA/NV has brought showers and isolated
thunderstorms to the region this afternoon, mainly from Highway 50
south. The greatest chance for stronger showers and reduced CIG/VIS
continues to be around KMMH and in eastern Churchill/Mineral
Counties where stronger convection is occurring. Shower activity
is expected to begin to dissipate by 04Z at KMMH.

A cold front moving through the region Tuesday will bring another
round of rain and mountain snow showers as well as an increase in
winds. Precipitation is expected to be relatively light but could
bring intermittent CIG/VIS restrictions and mountain obscuration,
especially to Sierra terminals. Winds could gust around 30-35 kts
Tuesday along the leading edge of the cold front, with the strongest
winds from hwy 50 north. Jet level winds could reach 100 knots on
Tuesday creating turbulence downstream of the Sierra. -Zach


.REV Watches/Warnings/Advisories...


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