645
FXUS63 KUNR 041920
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
120 PM MDT Thu Jul 4 2024

.KEY MESSAGES...

- Showers/storms and breezy winds will dissipate this evening
- Warmer Friday through Sunday with daily chances for storms
- Hot/dry weather develops next week

&&

.DISCUSSION...(This Evening Through Thursday)
Issued at 120 PM MDT Thu Jul 4 2024

An upper low spins over the northern plains, helping
to produce scattered showers/storms across the CWA. With a somewhat
tight pressure gradient at the surface, northwesterly winds are 15
to 25 mph with gusts around 35 mph. Temperatures early this
afternoon are in and around the 60s.

Showers/storms and breezy winds will gradually dissipate this
evening as the low shifts eastward. Temperatures will cool to the
50s and lower 60s this evening, then dip into the 40s some
places by early Friday morning.

With an upper ridge over the west coast, weak shortwaves moving
through northwest flow will cross the northern plains over the next
few days. Weak buoyancy and shear Friday afternoon will contribute
to more scattered, non-severe showers/storms. The main forcing
arrives in the evening, and with improving shear, some nocturnal
storms will be possible.

Another shortwave approaches Saturday afternoon/evening. Up to 60
kts of 0-6km shear across the southern half of the CWA would support
strong to severe storms, although buoyancy will be weak most places.
The best overlap of shear/CAPE/forcing in our area appears to be
south central SD, where there is currently a Marginal Risk.

Highs will be in the 70s to lower 80s Friday through Sunday. Warmer
and drier weather is expected early next week, as the western CONUS
ridge builds. Highs will be in the 80s on the plains Monday, with
temperatures increasing each day through next weekend. Probabilities
of reaching 100 degrees on the plains reach 50%+ next Friday and
increase to 70% for much of the CWA by next Saturday

&&

.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 954 AM MDT Thu Jul 4 2024

Chances for shower/storms through this afternoon with chances
diminishing toward the evening. Otherwise VFR conditions are
expected across the area. Breezy northwest winds, especially
across the western South Dakota plains, where gusts up to 35 kts
are possible.

&&

.FIRE WEATHER...
Issued At 120 PM MDT Thu Jul 4 2024

A pattern change to much drier and warm/hot weather
is foreseen for next week. Minimum afternoon relative humidities in
the 20s will be common by Wednesday, with some teens over
northeastern WY. Elevated fire weather conditions are
expected.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...Pojorlie
AVIATION...Wong
FIRE WEATHER...Pojorlie