Forecast Discussions mentioning any of "ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 07/14/23

Area Forecast Discussion

National Weather Service Reno NV

 146 PM PDT Thu Jul 13 2023

...Dangerous Heatwave Peaks This Weekend...

.SYNOPSIS...

Temperatures begin to ramp up on Friday as a well anticipated
heatwave moves into the region, bringing widespread heat related
health concerns this weekend. Several daily record highs will
likely be broken and all time record highs could even be in
jeopardy. A slight chance of a thunderstorm or two will arrive by
Sunday into Tuesday.

&&

.DISCUSSION...

No significant changes to the current forecast. We remain on track
for the heatwave to make its arrival by tomorrow with highs creeping
near, or just inside the triple digits for western Nevada valleys.
The ridge really builds into the region by Saturday, with good
agreement on 500mb heights within the 598-600dam range centered over
the Silver State. It`s going to be hot. Blended guidance still shows
very high confidence in breaking daily record highs on Sat and Sun
for several locations, including Reno. In fact, there remains a 25%
chance we will tie the all time record high at Reno this weekend of
108 (previously reached 3 other times) and a 10% chance we`ll
break the all-time record high. All of this to say it`s going to
be dangerously hot out there. This includes the higher mountain
communities of California like South Lake Tahoe and Bridgeport for
example, where some homes may not be equipped for highs in the
mid-90s.

The ridge begins to shift back over the Four Corners region early
next week. Beginning on Sunday, high clouds will move into the area.
Given an intrusion of moisture and mid-level CAPE, we are still
expecting a low-end chance (10-15%) of high base and potentially dry
thunderstorms later in the day on Sunday. Thunderstorm chances (10-
20%) increase further Monday-Tuesday, but shift from the Sierra
Front eastward due to the increased southwest flow. While
comparatively not as hot, we will still run 5 or so degrees above
average next week so don`t expect a significant reprieve in the
near future...

While overall fuels have still yet to reach critical thresholds this
summer, enhanced west/southwest winds during the work week along
with low daytime humidity and poor overnight recoveries will
certainly usher in a fire threat. This will particularly be true in
portions of western Nevada where some of the (abundant) fine fuels
like cheatgrass have had the chance to cure. Be mindful of things
like parking or idling your car on grass, dragging trailer chains,
littering cigarette butts, etc.

Very hot temperatures this weekend will continue the rapid high-
elevation snowmelt and subsequent high flows on small streams, as
well as the forks and mainstem of the Walker River. Please use
extra caution when recreating around local rivers and streams that
continue to run fast and cold.

-Dustin

&&

.AVIATION...

* VFR conditions will persist through the weekend, with south-
  southwesterly afternoon breezes gusting to 20-25 kts. Some
  enhancement to these breezes is expected early next week with
  gusts to 25-30 kts. Late afternoon cumulus congestus will build
  over the higher terrain through early next week, with less than a
  5% chance of these developing into thunderstorms today through
  Saturday.

* Very hot afternoon temperatures regionwide will lead to
  vigorous thermal development and subsequent turbulence. These
  hot conditions will also lead to density altitude concerns,
  especially Friday through Monday when high temperatures in
  western Nevada push 100-108 degrees. Most naturally aspirated
  aircraft will have a power equivalent to taking off at an
  altitude of 8000+ ft MSL at KRNO (field elevation is 4415 ft
  MSL). Make sure to take this into account when planning your
  flights Friday through Monday.

* Afternoon and evening thunderstorm chances of 10-20% will return
  beginning Sunday along the eastern Sierra and Sierra Front, then
  moving eastward along the western Nevada Sierra Front into the
  Basin and Range Monday and Tuesday.

-Johnston

&&

.REV Watches/Warnings/Advisories...
NV...Heat Advisory from noon Saturday to 8 PM PDT Sunday NVZ002.

     Excessive Heat Warning from noon Saturday to 8 PM PDT Monday
     NVZ001-003-004.

     Excessive Heat Warning from noon Saturday to 8 PM PDT Sunday
     NVZ005.

CA...Heat Advisory from noon Saturday to 8 PM PDT Sunday CAZ070>072.

     Flood Watch from Friday evening through Monday morning CAZ073.

     Heat Advisory from noon Saturday to 8 PM PDT Sunday below 7000
     feet for CAZ073.

&&

$$