645
FXUS65 KREV 132108
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
208 PM PDT Thu Jun 13 2024

.SYNOPSIS...

One more hot day today, then our attention turns to a dramatic
pattern shift this weekend into early next week. A couple dry cold
frontal passages bring a significant cooling trend through early
next week, with temperatures bottoming out well below average on
Monday. These systems will also bring increased afternoon winds,
with periods of elevated fire concerns Friday through Monday.

&&

.DISCUSSION...

The closed low off the coast of southern California tracks inland
today, introducing diffluent flow aloft over the region which will
support increased instability this afternoon. Model soundings
indicate greatest CAPE values (300-500 J/kg) for areas south of US-
50, generally between the Eastern Sierra and the US-95 corridor. As
such, today`s convective activity will favor these areas, mainly
during the 2 PM-8 PM timeframe. Forecast DCAPE values in these areas
are between 1400-1600 J/kg, indicative of the chance for some
isolated storms to produce strong to severe wind gusts. Other
threats include small hail, localized heavy rainfall, and new fire
starts from lightning strikes.

Otherwise, after another record-setting day for temperatures, we
have one more hot day in store today. High temperatures approach the
100 degree mark again across lower western Nevada valleys and top
out in the low-mid 80s for Sierra communities.

A major pattern shift looks increasingly likely this weekend into
early next week, with a couple upper-level shortwave troughs digging
into the western US. The first in the series drops into the Pacific
Northwest Friday into Saturday, introducing increased west-
southwesterly winds on Friday afternoon and evening. Widespread
gusts 25-35 mph are likely, with localized areas 40+ mph possible.
Winds stay elevated into the weekend as a general troughy pattern
remains over the western US. A secondary shortwave drops farther
south into northern California and Nevada on Monday. The trajectory
of this system promotes the potential for even stronger winds than
those observed on Friday. These strong winds, in conjunction with
widespread low daytime relative humidity, will support several
hours of critical fire weather conditions where fuels are cured.
Please refer to the Fire Weather section below for more details.

Ensemble cluster analysis supports a general weak troughing pattern
persisting through the remainder of next week, supportive of
seasonably warm temperatures and low shower and thunderstorm
chances. Whitlam

&&

.AVIATION...

VFR conditions with typical afternoon westerly breezes expected for
all regional terminals today. Showers and thunderstorms are expected
to develop over the Eastern Sierra this afternoon with coverage
expanding eastward into southern Lyon/Mineral counties this evening.
There is a 15-25% for thunderstorms to impact KCXP, KMEV, and KMMH
between 22-03z. Otherwise, expect mostly dry conditions to
prevail with some cumulus buildups through this evening. Whitlam

&&

.FIRE WEATHER...

A multi-hour period of critical fire weather conditions is likely
for the Sierra Front and Basin & Range on Friday afternoon.
Sustained west-southwest winds 15-20 mph with gusts to 25-35 mph,
coupled with daytime relative humidities of 10-15% will create a
3-6 hour window of Red Flag conditions across the aforementioned
areas. Due to increasing confidence, Fire Weather Watches have
been replaced with Red Flag Warnings, in effect 2-10 PM on Friday.
Note that the Churchill/northern Lyon county areas have been
added to this product -- recent fuels intel from cooperators in
the northern Lahontan Basin indicate fuels have reached critical
levels in this area.

Winds remain elevated into the weekend, yielding elevated to locally
critical fire weather conditions on Saturday and Sunday. Confidence
is increasing in another dry cold frontal passage on Monday, with
widespread critical conditions possible once again.

Avoid activities that could cause a spark! We`ve had multiple 100+
acre fires in the Truckee Meadows over the past few days, even with
sub-critical fire weather conditions. Whitlam

&&

.REV Watches/Warnings/Advisories...
NV...Red Flag Warning from 2 PM to 10 PM PDT Friday NVZ420.

     Lake Wind Advisory from 2 PM to 10 PM PDT Friday NVZ001>004.

     Red Flag Warning from 2 PM to 10 PM PDT Friday NVZ423-429.

CA...     Lake Wind Advisory from 2 PM to 10 PM PDT Friday CAZ071-072.

&&

$$