Heat in Nevada, September 6 to 8, 2022

Area Forecast Discussion
National Weather Service Reno NV
236 AM PDT Tue Sep 6 2022

...RECORD-BREAKING HEAT CONTINUES ACROSS NORTHEAST CALIFORNIA AND
WESTERN NEVADA THROUGH WEDNESDAY...

.SYNOPSIS...

Record temperatures will continue through midweek with 100+
degrees for the lower elevations. Today will be the hottest day
with temperatures easing gradually during the second half of the
week. Shower coverage will be mostly isolated today, then
shower and thunderstorm coverage will increase Wednesday,
especially from the Tahoe Basin and Reno southward along the
eastern Sierra. Cooler and cloudier conditions arrive this weekend
with shower chances increasing early next week.

&&

.DISCUSSION...

* Seems like a broken record, but the unusual heat to continue for
  a couple more days, then ease late week as the ridge weakens and
  500 MB heights begin to fall. Today will be the hottest day as
  700 MB temps are forecast to peak near 18-19C. This would put
  most western NV sites close to 105 degrees and Sierra valleys in
  the low 90s - with more records likely to be broken. This
  includes overnight lows for some spots like Reno which is
  currently forecast to be at an all-time September warmest
  Wednesday morning. Daytime temperatures will ease a few degrees
  Wednesday afternoon but not enough to preclude moderate-to-high
  end heat health impacts. As the ridge breaks down late week,
  temperatures will ease further but still be quite warm Thu-Fri
  as there is no front to bring a more notable cooling.

* Isolated-scattered showers will develop along the Sierra into
  far western NV this afternoon and evening. Like Monday, cells
  will struggle to reach much vertical depth with a lot of virga
  away from the higher terrain. Gusty outflow winds may still
  accompany showers. Moisture increases slightly Wednesday with
  ECS PWATS rising a bit into the 0.5-0.7" range from the Tahoe
  Basin southward. Most CAM runs indicated an uptick in intensity
  and coverage for Wednesday afternoon and we have bumped the pops
  toward a more scattered coverage in these areas with isolated
  potential spreading farther north into northeast CA/northwest NV
  as a weak shortwave brushes by to our north. Stronger storms
  Wednesday will be capable of outflow winds to 50 mph along with
  brief heavier rainfall. Storm coverage backs off a bit Thu-Fri
  as the east-west ridge axis shifts southward over the area.

* For the weekend into early next week, we continue to watch a
  trough approaching the west coast and how the remnants of
  Hurricane Kay will interact with it as it moves inland. Medium
  range models continue to pump a lot of mid-high level moisture
  northward into our area over the weekend which would dampen
  daytime heating/instability (PWATS increase to 0.80-1.00").
  Given a lack of any large scale forcing, it may just be a lot of
  clouds and only isolated showers/storms. Certainly cooler than
  we've been experiencing. The 00Z deterministic GFS/ECMWF are on
  board with bringing a long wave trough into the west coast at
  some point early-mid next week which could finally bring a large
  scale lifting mechanism/more widespread showers. ECS meteograms
  are beginning to show quite a few wet members late Sunday-Tues.
  700 MB temps cool significantly... so more seasonal temps are on
  order!

Hohmann

&&

.AVIATION...

* Buildups and isolated showers will be confined mainly to the
  eastern Sierra south of Hwy 50 (TVL-KMMH) this afternoon/evening
  with the lightning potential remaining low (5-10% chance). A few
  showers could drift up into the Tahoe Basin and Reno-Carson City
  area. Any cells that develop will be capable of gusty outflow
  winds to 30+ kts.

* An uptick in shower/lightning activity (15-25% chance) will
  occur from the eastern Sierra to the Tahoe Basin/Reno-Carson
  City area Wednesday afternoon with isolated potential spreading
  to most other areas as well. Some storm cells will be stronger
  than today's with outflow wind gusts 40+ kts possible along with
  brief heavy rain.

* Otherwise, typical late day breezes with gusts to 15-20 kts for
  area terminals. The unusually hot conditions may create some
  density altitude issues today and Wednesday.

Hohmann

&&

.FIRE WEATHER...

Very hot temperatures, dry conditions, and typical late day
breezes will continue through Thursday.

Since the winds will be fairly typical much of the week, there
are no critical fire conditions forecast. Primary concern will be
the potential for isolated thunderstorms Wednesday and Thursday,
primarily from the Tahoe Basin and Sierra Front down into the
Eastern Sierra. If any storms do develop, they will favor being
dry in nature given the hot and dry sub-cloud conditions, although
a few stronger cells could still produce locally heavy rain.
Gusty outflow winds to 40 mph from any showers/buildups today with
an uptick in cell strength Wednesday, capable of gusts to 50 mph.

There is an outside chance for some remnant tropical moisture
making its way northward this weekend into early next week which
will bring more seasonal temperatures along with the potential for
more widespread showers.

Hohmann

&&

.REV WATCHES/WARNINGS/ADVISORIES...
NV...Heat Advisory until 9 PM PDT Wednesday for NVZ001-003>005.

CA...Heat Advisory until 9 PM PDT Wednesday for CAZ070-071.

&&