Severe Thunderstorm Warning 12, NWS Reno, NV

Area Forecast Discussion
National Weather Service Reno NV
215 PM PDT Wed Jul 19 2023

.SYNOPSIS...

Another round of typical July heat and afternoon showers and
thunderstorms is on tap today. Drier and hotter conditions return
Thursday into the weekend, in addition to typical westerly afternoon
breezes. Heat health risk peaks Friday and Saturday as temperatures
soar to near record territory.

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.DISCUSSION...

Current satellite and radar depicts a cluster of fast-moving,
elevated showers and thunderstorms tracking east out of our region.
These storms impacted areas generally south of US-50 yesterday
afternoon and overnight, producing frequent lightning and localized
heavy rainfall. One portion of southern Lyon county saw training
storms that produced up to 4 inches of rain yesterday, which led to
a road closure on NV-338 due to flash flooding. Similar conditions
are anticipated today, with storms already firing over the high
Sierra in Mono County early this afternoon. Coverage will once again
mainly remain confined to areas generally south of US-50, with a 30-
45% chance of thunderstorms. Forecast soundings indicate inverted-V
profiles with DCAPE values between 1500-1800 J/kg which are
variables conducive to outflow gusts between 40-50 mph, perhaps even
in excess of 50 mph in stronger storms. PWATs around 0.8 inches will
provide ample moisture to produce brief heavy rainfall, but faster
storm motions today lessen chances for flash flooding.

There are still low-end chances (10-15%) for isolated showers and
thunderstorms Thursday afternoon over Mono and Mineral counties as
we squeeze out the last of the Pacific moisture. A ridge building
back into the southwestern US will squash additional precipitation
chances from Friday into the weekend, in addition to bringing much
warmer temperatures to the region. Peak heat looks to occur on
Friday and Saturday, with widespread moderate risk heat health
impacts and areas of major risk, especially across western Nevada
valleys. High temperatures will peak in the 100-105 degree range in
western Nevada valleys, and upper 90s to near 100 across Plumas,
Lassen, and E. Modoc counties.

Looking into early next week, temperatures moderate closer to
seasonal averages as a trough impinges on the PacNW coast. This
trough may also lead to enhanced west-southwest winds early next
week, especially for northern areas of the forecast area, generally
north of I-80. Whitlam

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.AVIATION...

Showers and thunderstorms are ongoing across portions of Mono,
Mineral, and southern Lyon counties this afternoon. There is a 30-
40% chance for a thunderstorm to impact KMMH/KHTH through 00z.
Expect brief periods of MVFR/IFR conditions for these terminals.
Main impacts from these storms include frequent lightning, gusty
outflow winds, small hail, and brief heavy rainfall.

Elsewhere, VFR conditions prevail today with typical west-southwest
breezes of 15-20 kts and cumulus buildups along the higher terrain.
Whitlam

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.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
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