Fort Pierre, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

968
FXUS63 KUNR 201113
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
513 AM MDT Fri Jun 20 2025

.KEY MESSAGES...

- Hot and (mostly) dry through Saturday afternoon with near
  record/record high temperatures
- Cooler/near seasonal temperatures and unsettled weather
  Saturday night through Thursday

&&

.DISCUSSION...(Today Through Thursday)
Issued at 125 AM MDT Fri Jun 20 2025

07z surface analysis had broad low over WY with boundary into
central SD. Just north of boundary per 700mb theta-e advection,
isolated shra/TS traversing far northeastern WY/northwestern SD.
Rest of CWA quiet as upper level ridge dominates the
central/southern plains per water vapour loop. Heat and ridge-
riders the main forecast concern in the short term.

Today/tonight, shortwave currently over ID/NV swings
northeastward into the northern plains pushing aforementioned low
northeast with warm front/thermal ridge surging northeastward.
Deep boundary layer mixing south of warm front will promote gusty
southwest winds and near record/record high temperatures this
afternoon. Current heat headlines look good. Tongue of Td/s in the
60s/lower 70s wraps eastward ahead of low into far northwest SD
which may be sufficient to break rather stout cap in place this
afternoon. If cap breaks, strong buoyancy would be released with
enough shear supporting raucous thunderstorms. Most CAMs keep
severe thunderstorms in ND, but a couple members show a strong
updraft track near the ND border. Low pops warranted in the far
north late this afternoon.

Saturday looks dry with even stronger cap. Near record/record
highs in jeopardy again given thermal ridge/deep boundary layer
mixing. Upper trough lurking over the Rockies will allow a cool
front to slip into the CWA Saturday night/Sunday which may be the
focus for some shra/TS. Upper trough slowly moves across the
northern plains early next week with a series of weak disturbances
bringing chances for TSRA along with cooler/near seasonal
temperatures. Confidence is high for the pattern change, but low
for the details, and in particular PoPs given NBM consistently
overdoes PoPs for convective weather in the summer.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Saturday Morning)
Issued At 512 AM MDT Fri Jun 20 2025

VFR conditions are expected through the period. Isolated
thunderstorms may occur near the MT/ND/SD border late this
afternoon.

&&

.FIRE WEATHER...
Issued At 125 AM MDT Fri Jun 20 2025

Elevated fire weather conditions are expected today and Saturday.
MinRH today will bottom out around 10-15% for the southwest half
of the area this afternoon and then teens for Saturday across the
southern half of the area. Reports for land managers indicate
most fuels not conducive to large fire weather growth, but local
spots might be if recent precipitation was missed.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Heat Advisory from 1 PM this afternoon to 9 PM CDT Saturday for
     SDZ046-047-049.
WY...None.
&&

$$

DISCUSSION/KEY MESSAGES...Helgeson
AVIATION...Helgeson
FIRE WEATHER...Helgeson