Area Forecast Discussion
Issued by NWS Reno, NV

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FXUS65 KREV 272121

Area Forecast Discussion
National Weather Service Reno NV
221 PM PDT Sat May 27 2017


Cold and swift flows along with areas of minor flooding will
continue near creeks, streams and rivers this Memorial Day weekend
as the spring Sierra snow melt continues. A warming trend will
continue into early next week as high pressure builds. Light winds
with some cumulus build ups are possible near the Sierra this
weekend, with a few showers and storms possible next week.


.SHORT TERM...through Tuesday Night...

Temperatures will continue to warm though the holiday weekend as a
ridge of high pressure strengthens across the region. High
temperatures are likely to peak on Monday/Tuesday 10 to 15 degrees
above normal, or around 90 for western Nevada valleys and in the
upper 70s in Sierra valleys.

Conditions will be dry today and Sunday with mainly some afternoon
cumulus development. By Monday, an approaching trough will begin to
weaken the ridge and destabilize the atmosphere, likely allowing for
isolated thunderstorms to develop mainly over the higher terrain of
the Sierra. With the overall flow still fairly light, storms should
remain fairly stationary. Additional storms are possible on Tuesday
as the trough begins to move inland and instability lingers. With
increasing southwest flow, storms are likely to be pushed off the
Sierra and possibly into Mineral, southern Lyon, and Churchill
counties. Any storms that develop will be short-lived and isolated
in nature.

The main concern through the period (and really for the next several
weeks) continues to be the snowmelt flooding that is occurring through
the region. The diurnal response on rivers, creeks, and streams
last night was less than in past days due to colder temperatures.
As temperatures warm, responses are likely to increase as well,
likely peaking the early or middle part of next week before a
cooler airmass works into the region. See the flood products that
are in effect for specific details. Please use extreme caution
near any bodies of water and stay safe! -Dawn

.LONG TERM...Wednesday through Saturday...

A weak splitting trough will move over California and Nevada on
Wednesday. This could bring a few showers to eastern California and
western Nevada into the evening. Instability for thunderstorms looks
limited as the upper forcing will be weak and surface temperatures
cool down between Tuesday and Wednesday. However, a slight chance
for thunderstorms was left in the forecast as very isolated
afternoon/early evening storms cannot be ruled out at this time. One
thing the trough is sure to do is bring considerably cooler
temperatures (10 degrees or so) for Wednesday.

The trough moves east for Thursday, which should bring an end to any
shower threat. Some ridging is expected behind the trough, but how
strong is the question. The 00Z ECMWF spaghetti plots and the 12Z
operational ECMWF indicate a moderate strength ridge into Saturday,
while the 12Z GFS has more zonal flow under a stronger Northwest
CONUS trough. Either way, the result may not be all that different
outside of temperatures and a slight increase in the thunderstorm
threat. If the ECMWF were to pan out, high temperatures would be a
few degrees warmer than forecast late next week, with isolated late
day thunderstorms possible in the favored areas of Mono and Mineral
Counties. Snyder



VFR with light winds (generally less than 10 kts) tonight through
Monday. Sunday, afternoon cumulus should develop over the Sierra
south of Highway 50 but no thunderstorms are expected. However,
there is a threat for isolated thunderstorms over the Sierra
mid-afternoon to early evening Monday. Snyder


.REV Watches/Warnings/Advisories...


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