480
FXUS65 KREV 042144
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
244 PM PDT Thu Jul 4 2024

.SYNOPSIS...

* A long duration heatwave is expected that will result in a
  moderate to major HeatRisk lasting through at least the middle of
  next week.

* Dry conditions continue into next week with chances of showers
  and storms remaining below 5% through the weekend.

* Breezy afternoon winds may produce elevated to locally critical
  fire weather conditions on Sunday.

&&

.DISCUSSION...

The latest RAP upper air analysis shows the CWA being underneath
the eastern portion of a large high pressure ridge this afternoon.
Current surface observations and satellite imagery report dry
conditions as well light and variable winds across most of the
region underneath sunny skies. Southern Mono County however does
have some high clouds forming as an exception to the previous
statement. Going through the rest of the day and through the
weekend, forecast guidance projects the ridge slowly moving
eastward where it continues to control the upper air pattern over
the western CONUS. Models then show the axis of this ridge passing
over the CWA on Tuesday afternoon along with a weak upper air low
moving off the coast of the Baja Peninsula. On Wednesday, model
guidance projects the CWA to be underneath the western portion of
the ridge as the ridge`s advance continues with the aforementioned
upper air low moving northward over the CA coast. What this upper
air pattern translates to down at the surface is that temperatures
are expected to continue to rise to above normal values going
into the weekend and into the beginning of next week. It does not
look that until the later half of next week that this heat will
break and it could be a slow decline at that.

While dry conditions are mostly expected to prevail, the main hazard
for the upcoming days will be the above normal temperatures and
heat. While the region expects to top off in the 80s and 90s for
high temperatures today, some areas of western NV including the Reno-
Tahoe International airport see around a 70% chance of hitting the
century mark today. The NBM probabilities of 100F or greater then
increase to between 70-90% with the coverage starting to expand a
bit on Friday. By Saturday, these NBM probabilities cover a good
portion of the western NV portion of the CWA along with portions of
northeastern CA while the upper limit raises to around 95%. As this
looks to remain this way going through next week along with the
expected moderate to high HeatRisk in the region, the Excessive
Heat Warning for western NV and the Heat Advisory for the CA
portion of the CWA continues for Saturday through Wednesday.
Please see the heat products for more detailed information on
these upcoming heat hazards. It is recommended to take precautions
during this time such as limiting outdoor activity, taking breaks
in a cool area, staying hydrated, and checking in on neighbors
and relatives that may be more susceptible to heat related
illness. For more heat safety tips, please visit
weather.gov/safety/heat. Near record to record high temperatures
and warmest low temperatures are also possible for this weekend
and going into next week.

While models show the CWA staying dry through the weekend, they
do show single probabilities of precipitation returning next week
which are still pretty low. There may be a chance that they
increase when the ridge starts to depart in the latter half of
next week. But for right now, the precipitation chances look to be
rather low. Will continue to monitor to see if these chances do
increase in future model runs or if there is a chance for some dry
lightning that may cause a fire weather concern. Also with the
ongoing CA wildfires, will be monitoring for potential smoke in
the area though for now there may be some slightly hazy skies in
some locations for a bit. -078

&&

.AVIATION...

VFR conditions continue at all REV TAF sites through the remainder
of the holiday and going into tomorrow. Models show clear skies over
the region with the exception of a few clouds over western NV
tonight during the overnight hours. Typical afternoon breezes are
also in the forecast across the region with KMMH possibly seeing
gusts up to around 20 kts between 20Z-03Z. Well above normal
temperatures through the weekend and into next week still look to
result in density altitude concerns across the whole area. -078

&&

.FIRE WEATHER...

No major changes from the previous fire weather forecast package
with well above normal temperatures, low daytime relative humidity
values, and dry conditions prevailing for the rest of the week and
into next week. However, winds look to a limiting factor as they are
generally light and unsupportive of critical weather at least
through the remainder of this week. Beyond this week, models are
hinting at some gusts near or above 30 mph starting on Sunday within
the Sierra and Sierra Front areas. So, will continue to monitor
these conditions over the next few days as this could lead to
periods of elevated to locally critical fire weather conditions for
those localized areas. There are also some very slight chances for
showers and thunderstorms starting on Sunday afternoon. However,
these chances remain at or below 5%. -078

&&

.CLIMATE...

Record High and Warm Low Temperatures for July 6th-9th
at Reno-Tahoe International Airport (KRNO)
-------------------------------------------------------

DateRecord High Record Warm Low
------          -----------             ---------------
July 6101F 71F

July 7102F 68F

July 8104F 71F

July 9104F 69F


&&

.REV Watches/Warnings/Advisories...
NV...Heat Advisory from 10 AM Saturday to 10 AM PDT Wednesday NVZ002.

     Excessive Heat Warning from 10 AM Saturday to 10 AM PDT
     Wednesday NVZ001-003>005.

CA...Heat Advisory from 10 AM Saturday to 10 AM PDT Wednesday
     CAZ070>073.

&&

$$