Box Elder, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

758
FXUS63 KUNR 112328
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
528 PM MDT Sat Apr 11 2026

.KEY MESSAGES...

-Warm and mainly dry this weekend with isolated showers possible
 this evening

-Critical fire weather conditions for parts of the area through
 Monday, mainly along and south of I90

-Upper trough will bring some precip chances to the region Tue
 with additional chances toward the end of the week

&&

.DISCUSSION...(This Afternoon Through Friday)
Issued at 1126 AM MDT Sat Apr 11 2026

Upper trough will continue to dig into the western CONUS, with
continued downstream ridging to the east. This will support warm
and mainly dry weather through Monday. Although a few isolated
showers will be possible tonight as a lead impulse crosses the
area. Dry SW flow is ongoing across the SW FA. As mixing and
pressure falls continue, expect flow to increase this afternoon
across the southern half of the FA. A lead impulse will shift the
lee-side trough into the FA later in the afternoon/evening. Enough
high level moisture and instability will be in place to force
isolated very high based showers and perhaps a few TS, esp over NE
WY and far SW SD. Gusty winds would be expected with any
convection that does develop given inverted V profiles in a deeply
mixed BL. Shower activity will carry northeast through the
evening. Sfc trough will push into the area and stall as the main
upper trough pushes east into the Rockies. This will support
another mild day across the region Sunday with highs in the 70s, a
few low 80s in scentral SD. Dry SW flow can be expected due to
continued very dry BL conditions. This process will repeat Monday
as the cool front will be delayed by the next sfc low ejecting
into region. Cool front starts to progress east into the area
Monday night with increasing upper level moisture. This could
support a few showers by afternoon into the overnight hours across
the NW third. As the main upper trough moves across the region
Tues, slightly better coverage is anticipated, but less than
previous model runs as the bulk of moisture remains south and east
of the FA. Hence trended pops down Tue, with Wed likely dry. Mild
weather will continue through Thur as WAA ensues ahead of the
next upper trough which will advect ESE in westerly flow out of
the Pac NW. This system will bring another round of precip chances
to the region toward the end of the week, although confidence in
chances and amounts remains low given the time period.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening)
Issued At 528 PM MDT Sat Apr 11 2026

Isolated to scattered thunderstorms will continue this evening
across northeast WY and far western SD. Local MVFR conditions and
variable/gusty winds up to 40 knots are possible with any stronger
precipitation. Otherwise VFR conditions are expected through the
TAF period. Breezy conditions will continue overnight into Sunday.

&&

.FIRE WEATHER...
Issued At 1126 AM MDT Sat Apr 11 2026

Gusty southwest winds, very dry air, and lack of appreciable
green up will support critical fire weather conditions through
Monday over portions of northeast WY and western SD, mainly along
and south of I90. In addition, there is a the potential for late
afternoon/early evening isolated dry TS, especially over northeast
WY and far SW SD today. A red flag warning remains in effect and
has been extended through Sunday, however, critical fire weather
conditions are likely again Monday as dry SW flow continues along
and south of I90 with another extension of the red flag warning
likely needed. A low pressure system will move into the region
early next week, potentially bringing some precipitation to the
area, although rain chances have trended down. Cooler and
unsettled toward next weekend.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning until 9 PM MDT Sunday for SDZ320>322-324>326-
     329-332.
     Red Flag Warning from 11 AM MDT /noon CDT/ to 9 PM MDT /10 PM
     CDT/ Sunday for SDZ331-333>335.
WY...Red Flag Warning until 9 PM MDT Sunday for WYZ314-315-317.
     Red Flag Warning until 8 PM MDT this evening for WYZ316.
&&

$$

DISCUSSION/KEY MESSAGES...JC
AVIATION...13
FIRE WEATHER...JC