128
FXUS63 KUNR 291231
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
631 AM MDT Sat Jun 29 2024

.KEY MESSAGES...

-Cool today with temps in the 60s and 70s.

-Moisture returns Sunday with near daily chances for storms
 through next week.

-Seasonal temps next week, with some days on the cooler side of
 normal.

&&

.DISCUSSION...(This Afternoon Through Friday)
Issued at 631 AM MDT Sat Jun 29 2024

Semi-active northern stream will prevail next week with daily
chances for showers and storms as a frontal boundary wavers over
the region. Temps will be around seasonal norms with a few days on
the cool side of normal with highs in the 70s. Sfc high has built
into the region with a dry cp airmass in place. Stratus over NW
SD will linger through morning, supporting fall like conds there
as temps will only top out in the 60s. Elsewhere 70s are expected
with dry conds. Return flow will ensue tonight with pos theta-e
adv ongoing through Sunday. Isold TS are possible late tonight on
the SD plains as the LLJ advects moisture into the region aloft.
Staunch SE flow per pressure falls will support breezy conds with
near adv level winds on the SD plains. Much warmer temps can be
expected Sunday with highs in the 90s in the west, and upper 80s
east. Weak impulse will interact with the lee side trough/dryline,
supporting isold TS in the afternoon, with convection carrying
across NW SD overnight. Severe threat looks less impressive than
yesterday as moisture return, namely the depth of moisture is much
less robust in the west. Hence capping will tend limit storm
strength most places as CAPE profiles are not that impressive. Not
to say that an isolated stronger storm is possible given bulk
shear profiles with over 40 knots of shear. Main upper trough and
associated forcing will support a better chance for showers and
storms Monday, esp toward central SD where deeper moisture will be
in place. Expect unsettled flow the remainder of the week with
near daily chances for storms as some monsoon moisture and gomex
moisture interacts with passing impulses and a sfc front wavers
over the region.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Sunday Morning)
Issued At 511 AM MDT Sat Jun 29 2024

Low clouds and MVFR cigs will persist across portions of far NE WY
and NW SD this morning, although no impacts are expected at KGCC
or KRAP. Otherwise, VFR conditions are expected through the
forecast period.

&&

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

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...SE