202
FXUS65 KREV 140851
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
143 AM PDT Tue May 14 2024

.SYNOPSIS...

Additional showers and isolated thunderstorms will be possible
this afternoon across portions of the E.Sierra mainly south of
US-50. Otherwise expect unseasonable warmth to persist into the
start of the weekend with slow cooling and a potential return of
afternoon showers and isolated storms by Saturday into next week.

&&

.DISCUSSION...

Our mid/late June-like temperatures continue today as W.Nevada
valleys warm into the mid-80s with low 70s across Sierra valleys.
The warmest days of the week are targeting Thursday-Friday where
high temperatures could touch the 90 degree mark across western
Nevada which Reno hasn`t seen since September. While not record
breaking, this early season heat could yield some moderate heat
risks for heat sensitive individuals.

Today`s heating combined with influence from an upper level low
offshore of S.California could provide additional chances of
showers and thunderstorms again this afternoon. Areas along the
Sierra crest across Alpine and Mono counties will see the best
chances for development today (15-25% chance) with initial
development after about 2pm. These storms could be capable of
small hail, lightning, and gusty outflow winds up to 45 mph. These
storms will be embedded in an easterly steering flow, so there
will be less chances for these storms to drift into W.Nevada.

Drier conditions will arrive on Wednesday as the eastern edge of a
high pressure ridge builds into the region. This will add a few
degrees of warming into the weekend along with weak humidity
recoveries across mid-slopes and upper ridgetops across the
western Nevada Tuesday and Wednesday nights.

Temperatures will begin a steady cooling trend from Saturday into
next week as an upper level trough drops across the Pacific
Northwest. Still some considerable uncertainty with how this
trough merges with an existing low off of S.California, but
overall things are looking cooler with a potential return of
afternoon showers and storms by late weekend into next week.
Fuentes

&&

.AVIATION...

* Afternoon showers and thunderstorms will be possible this
  afternoon across portions of the eastern Sierra mainly south
  US-50 through Alpine and Mono Counties. Overall, chances will be
  less than on Monday for western Nevada terminals.

* Expect shower/storm development across the Sierra from about
  21z-03z today with 5-10% chances expected for KTRK/KTVL and 25%
  chances at KMMH. Erratic outflows to 40 knots, along with
  lightning and brief MVFR flight categories will be possible.

* Drier conditions with unseasonable warmth will persist into the
  start of the weekend with some cooling and a potential return
  of showers and storms by Saturday. Fuentes

&&

.HYDROLOGY...

Unseasonably warm daytime temperatures and mild nights, combined
with higher solar angles, longer days, and limited cloud cover,
will continue to increase snowmelt rates this week. Even the
higher elevation deeper snow areas will begin to melt in earnest.
This rapid melt will lead to elevated flows with rivers and
streams running cold and fast, most notably in areas draining
significant terrain over ~7500 feet from Lake Tahoe south through
Mono County.

While these high and cold flows can be hazardous to recreationalists,
flooding is very unlikely. Remember the highest flows are
significantly lagged from the heat of the day and can often occur
at night.

More steady high flows will also continue along the Lower Humboldt,
with additional rises likely in very late May or early June.

Please use extra caution around local rivers and streams which
will be running fast and cold. Bardsley

&&

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

&&

$$