159
FXUS63 KUNR 141109
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
509 AM MDT Thu May 14 2026

.KEY MESSAGES...

-Warm and windy this week with critical to near critical fire
 weather conditions the rest of the week

-Cooler early next week with some chances for showers

&&

.UPDATE...
Issued at 457 AM MDT Thu May 14 2026

Updated the wind advisory to start as the front moves through
northwestern South Dakota since wind gusts up to 55 mph will be
common along and behind the front.

Additionally, a low level jet has combined with decaying showers
across south central South Dakota. This has resulted in wind
gusts of 55 to 60 mph across much of Tripp County.

&&

UPDATE Issued at 1011 PM MDT Wed May 13 2026

Isolated showers and thunderstorms will continue to move across
northeast WY and western SD tonight as the surface-low over southern
AB continues to move east. Gusty winds (~40-50 mph) are associated
with these showers, with little to no precipitation reaching the
ground. Expect thunderstorms to continue to weaken throughout the
night as they push through western SD. The cold front associated
with the low will begin to push into the region early Thursday
(~7Z-9Z) and shift winds west/northwesterly. The strongest winds
behind the cold front will be over northwest SD, where a Wind
Advisory is in effect from 9 AM to 6 PM MDT for west winds of 25
to 35 mph, with gusts up to 55 mph. Thursday will bring
temperatures in the 80s across much of the SD plains ahead of the
cold front, with 70s behind it. RH values will drop into the low-
teens to single digits. Due to these conditions, the RFW will
continue to be in effect through 9 PM MDT for much of the SD
plains. Friday will be similar to Thursday, with comparable
temperatures, RHs, and gusty winds over northwest SD. However, the
stronger winds are not expected to overlap with the lowest RHs,
so a RFW currently appears unlikely. Cooler temperatures and
increased RHs will return by the end of the weekend and into the
beginning of next week with increased chances for precipitation.

&&

.DISCUSSION...(This Afternoon Through Tuesday)
Issued at 1121 AM MDT Wed May 13 2026

Western CONUS ridge will remain in place most of this week,
supporting warm and dry weather. Ridge topping impulses will
support weak cool fronts at times, with little to no precip with
each system. Breezy southeast winds have developed across western
SD in response to the advancing Pac NW upper trough. Associated
frontside impulse will shift east into NE WY later this afternoon
and evening. Sufficient LL moisture should be in place for
isolated high based showers/TS. If convection does develop, gusty
winds would be expected per inverted-V profiles. Any convection
will shift NE overnight in very isolated fashion. Retained low
pops for this. Sfc trough will shift through the FA tonight into
Thur morning, supporting gusty NW winds. Breezy winds can expected
Thur, esp over NW SD where adv level winds are expected with
gusts over 50 mph at times. Issued a wind adv for this. Breezy NW
winds will continue into Friday as another weak impulse advects
through westerly flow on the south side of the deeper southern
Canadian upper trough. Deeper upper trough will move into the
Rockies this weekend, leading to much cooler temps by Sunday, as
well as slightly better chances for showers into early next week.
However, the bulk of moisture stays east of the FA, with more
isolated to scattered activity expected in the FA. Expect highs
in the 50s and 60s most places Monday and Tues, with some 40s in
the west Monday, before things start to warm back up Wed. Some
frost will also be possible in this period, esp across northeast
WY.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Friday Morning)
Issued At 457 AM MDT Thu May 14 2026

A cold front will continue to cross the area this morning, pushing
through the Black Hills by 13Z and south central South Dakota by
18Z. Behind this front, gusty west to northwest winds of 30 to 45
kts are expected, especially across northwestern South Dakota.
Gusty winds will diminish around sunset tonight.

&&

.FIRE WEATHER...
Issued At 1121 AM MDT Wed May 13 2026

Warm, dry and, windy conds with receptive fuels will continue to
support critical to near critical conds to most of western SD
through the end of the week. A red flag warning remains in effect
through Thur, with a long duration of critical fire weather
conditions expected. Breezy SE winds today ahead of a trough of
low pressure. Very dry conds, with RH`s expected to fall to as low
as 10 percent both today and Thur afternoon (Friday as well). The
trough will move through this evening and support gusty NW winds,
with poor overnight recovery. Gusty NW winds will continue Thur
with continued very dry profiles. Dry and breezy through Sat. The
red flag warning will most likely need extended across southwest
SD Friday as critical fire weather conditions are forecast. Cooler
with shower chances early next week, leading to a break in fire
weather concerns although the best chance for wetting rains will
be east of the area.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 6 PM MDT this evening for SDZ001-002-012-013-
     078.
     Red Flag Warning until 9 PM MDT this evening for SDZ322>327-
     329>333.
WY...&&

$$

UPDATE...MLS
DISCUSSION/KEY MESSAGES...JC
AVIATION...MLS
FIRE WEATHER...JC