882
FXUS65 KREV 052042
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
142 PM PDT Fri Jul 5 2024

.SYNOPSIS...

* Prolonged heat wave bears down on the Sierra and western Nevada
  today and continues into next week. Plan on major heat risk
  impacts, even in the mountains. Please take this one seriously!

* No major wind signals are in the forecast. Fire concerns remain
  with hot temperatures, very dry air and any remaining holiday
  weekend activities. Localized haze is also possible from ongoing
  California wildfires.

* Isolated afternoon thunderstorm chances may return next week
  within the region with the best chances seen on next Friday, but
  low confidence continues at this time.

&&

.DISCUSSION...

The latest RAP analysis shows an upper air high off the coast of
northern CA that controls a large ridge over the western CONUS.
Current surface observations and satellite imagery continue to
report light winds and dry conditions underneath sunny skies for the
region this afternoon. Forecast guidance predicts the upper air
ridge residing over the western CONUS going through the weekend
before moving slightly eastward and tilting in a positive
orientation so that the ridge`s axis passes over the CWA on
Tuesday. Models then have the ridge continuing eastward through
the remainder of the work week with an embedded weak upper air
trough passing over the CWA on Thursday and Friday though the latest
runs of the long term models show some uncertainty in the exact
timing. This evolution in the upper air pattern means that the
surface will continue to see well above normal temperatures and
dry conditions through the weekend and into the next week. But by
the tail end of the next work week, the region may see
temperatures starting a slow decreasing trend with precipitation
chances rising slightly (10-15%) south of US-50 on Friday.

While monitoring of the next week`s trend change will continue, the
main story continues to be the near record to record high
temperatures and warmest low temperatures in the forecast (See
Climate Section for some local records) due to the heat expected
this weekend and the beginning of next week. Overall, some areas
within the CWA expect to see triple digit daytime high
temperatures through the weekend and through next week at this
time. As the CWA expects moderate to major 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 Excessive Heat Warning and Heat
Advisory 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.

While models show the CWA staying dry through the rest of this week,
they continue to show single probabilities of precipitation
returning next week which are still pretty low. As mentioned earlier
in the discussion, the latter half of next week may see a slight
increase in precipitation chances. Will continue to monitor to see
if better confidence for precipitation seen in future model runs or
if there is a chance for some dry lightning that may cause a fire
weather concern. Hazy conditions are also possible in the CWA as
well with the ongoing CA wildfires, so 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 again today and are
expected going into the weekend. Typical afternoon breezes are also
in the forecast across the region with KMMH again seeing gusts up to
around 20 kts between 23Z-03Z. Well above normal temperatures
through the weekend and into next week still may produce periods of
density altitude concerns across all TAF sites in the Sierra and
western NV. -078

&&

.FIRE WEATHER...

No changes made from the previous fire weather forecast. High
confidence for well above normal temperatures, low daytime relative
humidity values, and dry conditions persisting through next week.
Winds will remain light with only late afternoon breezes up to 20
mph possible.

As for next week, our more typical afternoon/evening breezes may
return with gusts in the 30 mph range as models show the upper air
ridge shifting slightly eastward. Fire concerns will remain with the
hot temperatures and very dry conditions as well as any remaining
holiday weekend activities. There are also some very slight (<5%)
chances for showers and thunderstorms starting on Sunday afternoon
and going into the beginning of next week. -078

&&

.CLIMATE...

Record High and Warm Low Temperatures for July 6th-9th at Reno-Tahoe
International Airport (KRNO)
-------------------------------------------------------
Date     Forecast(High/Low) Record High(Year)Record Warm Low(Year)
------   -----------------   ----------------   --------------------
July 6  105/66   101F(2021+)71F (2007)

July 7  106/71   102F(2014)68F (2004++)

July 8  106/70   104F(2017)71F (2014)

July 9  106/69   104F(2021)69F (2021)

+ denotes record also seen in 2014

++ denotes record also seen in 2001

Current record for consecutive days of 100F or greater at KRNO is 10
days, set in July 2021 and July 2005. The record for consecutive
days of 105 or greater is only 2 days, which has occurred 6 times in
climate history, most recently July 2023. Both of these have the
potential to be broken with this heatwave.

&&

.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.

&&

$$