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This is Jim Wallmann with the National Weather Service in Reno with an online weather briefing
for the record high temperatures though Saturday and thunderstorm potential Sunday. These online
presentations will be updated for major weather events as time and staffing resources permit.
Strong high pressure will build over northern California and Nevada today and peak on Saturday.
With the high, very hot temperatures are expected with readings as much as 20 degrees above
normal. The image shows the temperatures forecast for the peak Saturday afternoon near 10,000
feet above sea level which is a useful forecast tool for high temperatures. The warmest temperatures
shown in red are above 60 degrees at this level, with a legend for the temperatures
at the right. Temperatures are expected to warm further
Friday and Saturday with records becoming more widespread, with all locations in the
table expected to exceed record highs Saturday. In fact, if Reno were to reach 100 degrees
either Friday or Saturday as forecast, it would be the earliest the mercury has reached
100 degrees in Reno. The previous record earliest 100 degree reading occurred on June 13th,
1940. On Sunday, the weak upper low off the Southern
California coast is expected to move northward toward the Sierra and Western Nevada. As it
does so, it will bring some mid-level moisture shown in the green shading. The forcing from
the low, the hot temperatures and added moisture are expected to fuel scattered thunderstorms
Sunday afternoon. This combination may create some fire weather concerns, as the thunderstorms
are expected to be dry initially before transitioning to wetter storms by evening. The timing of
this transition and exactly how widespread the thunderstorms will be are still in question.
Here is our confidence in the forecast. Confidence is very high with the record setting hot temperatures
through Saturday. On Sunday, our confidence is moderate on thunderstorm formation, but
it remains low for the thunderstorm mode being primarily wet or dry in addition to how quickly
the storms will transition to wetter storms. The impacts for the forecast will be the heat
for the next three days. Remember these safety tips when outdoors and please keep a closer
eye on the elderly, children, and pets. For the thunderstorms Sunday, dry lightning could
spark new wildfires and also produce wind gusts over 50 mph. The thunderstorms are expected
to become wetter Sunday evening when some brief heavy rainfall may become possible.
Check back at our website for updates as heat and thunderstorms impact our region through
Sunday into Monday. An update to the online briefing is expected by early Friday afternoon.