306
FXUS65 KREV 090852
AFDREV

Area Forecast Discussion
National Weather Service Reno NV
152 AM PDT Sun Jun 9 2024

.SYNOPSIS...

The early season heat continues to decrease a bit today and
tomorrow before rebounding on Tuesday and Wednesday. Chances for
showers and thunderstorms are anticipated this afternoon and
evening, with best chances near the Oregon border and lesser
chances in southern Mineral and Mono Counties. Otherwise, near-
record or perhaps record breaking temperatures are expected to
develop again during the work week before conditions cool down
closer to normal going into the weekend.

&&

.DISCUSSION...

Upon looking at the latest RAP analysis early this morning, the CWA
has a southwesterly upper air flow being between a trough to the
west and a ridge to the east. Current radar imagery and surface
observations report some lingering isolated showers in western NV
with dry conditions in northeastern CA. Going through today,
forecast guidance projects the axis of the upper air trough to move
over the CWA by the late afternoon/evening hours while an upper air
low develops off the coast of southern CA. This upper air pattern
will cause a surface low to pass from the ID/OR/WA border into
southern ID through the day allowing for a cold front to set up near
northern portions of the CWA closer to the OR border. With this
surface setup, daytime temperatures are still expected to be above
normal though highs look to be around 5 degrees cooler compared to
yesterday`s highs. Northern portions of Lassen and Washoe
counties will see around a 20-40% chance for isolated showers
during the afternoon and evening (higher chances near the OR
border) that diminish going into the night. Models also depict
around a 15-25% chance for isolated showers in Mono and southern
Mineral Counties during the afternoon and evening. When looking
at the latest model convective parameters for the area, there
appears to be SBCAPE values up to around 500 J/kg in these
locations with some 0-6 km bulk shear around 30-40 kts making an
isolated thunderstorm or two possible. These storms look to stay
sub-severe though there may be some breezy outflow winds at times
associated with them. Otherwise, the typical afternoon zephyr
winds continue in the afternoon with gusts around 20-25 mph.
Western NV expects to see overnight lows in the 50s to lower 60s
range while the Sierra portions of the CWA look to have lows in
the 40s and 50s.

For Monday, models forecast an upper air ridge moving over the CWA
during the day with a cutoff upper air low moving off the coast of
the Baja Peninsula. Mostly dry conditions are anticipated at the
surface throughout the day as a result with daytime high
temperatures similar to those on Sunday. Forecast guidance shows
this pattern continuing through Tuesday and Wednesday allowing for
daytime high temperatures to rise to near-record to record values
once again around 15 degrees above normal. As these highs may rival
the records set during a heatwave in 1940, it is recommended to be
prepared once again for hot conditions on these days. While the
upper air ridge is forecast to stay over the CWA on Thursday, the
southern low is projected to move across southern CA by Thursday
night as a trough moves into the Pacific Northwest. Dry conditions
and above normal daytime conditions expect to persist for another
day though the temperatures may be a few degrees cooler than those
of the previous two days.

While the upper pattern looks mostly unsettled on Friday and going
into the weekend, long term ensemble guidance depicts the
aforementioned trough progressing over the northwestern CONUS.
This will allow temperatures to begin to gradually cool closer to
normal by the weekend. As for precipitation chances, models
currently show very low chances across the region this weekend.
Will continue to monitor this in case models start to change their
long term solutions. -078

&&

.AVIATION...

* Density altitude concerns will continue today as high
  temperatures remain around 10 degrees above average. Westerly
  winds prevail for all regional terminals beginning around
  20-21Z, with gusts generally 15-25 kts before winds diminish
  around 04Z Monday.

* Portions of the region near the OR border see a 20-40% chance
  for isolated showers and thunderstorms during the afternoon and
  early evening today while Mono and southern Mineral Counties
  see a 15-25% chance between 18-03Z. -078

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$