Lead, South Dakota 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

699
FXUS63 KUNR 261729
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1129 AM MDT Thu Mar 26 2026

.KEY MESSAGES...

- Critical fire weather conditions continue through this evening
  with a RED FLAG WARNING in effect for northeast Wyoming, the
  Black Hills, and southwestern South Dakota through 10 PM MDT.

- A few light rain showers and breezy conditions are expected
  Thursday with high temperatures 30 degrees cooler than today,
  only topping out in the 40s and 50s.

- A warming and drying trend returns for Friday through Monday,
  with low forecast confidence thereafter.

&&

.UPDATE...
Issued at 933 PM MDT Wed Mar 25 2026

Main change to the previous forecast was to raise pops tonight
into Thursday and lower temps the next couple days. Potent jet
streak will settle south overnight as a sfc cold front does the
same. Entrance region of the jet, ample Pac moisture, and strong
FGEN forcing will support bands of precip through Thur, esp across
NW SD. Rain will change to or mix with snow across NW SD and the
higher elevations of the BH Thur, with accums up to an inch
possible in those locations. Given precip and clouds, lowered
highs Thur a few degrees (in line with hires trends), esp across
the western third. Did the same for lows Thur night and highs Fri
as a decent batch of CP air will settle over the region.

&&

.DISCUSSION...(This Evening Through Wednesday)
Issued at 211 PM MDT Wed Mar 25 2026

A combination of record warm temperatures, gusty winds, low relative
humidities, and ongoing drought will continue to support yet another
period of critical fire weather conditions through this evening, and
the ongoing RED FLAG WARNING remains unchanged and in effect through
10 PM across northeast Wyoming, the Black Hills, and portions of
southwestern South Dakota. The highest confidence in these
conditions remains across southern Campbell and Weston counties in
Wyoming down across Custer and Fall River counties in South Dakota,
where a few stations have already reported wind gusts in excess of
30 MPH and RH values as low as 14 percent early this afternoon. Keep
in mind that even where humidity values remain closer to 20 percent,
it won`t make any meaningful difference in the risk of fire spread
with extremely dry fuels in place.

Cooler, more humid air takes hold of the region tonight and
Thursday, with breezy conditions and a chance of light rain showers
spreading in from north to south starting generally after midnight
tonight. Showers may reach as far south as Gillette, Rapid City, and
Philip through the morning, spreading further south during the
afternoon. Activity will be isolated to scattered for most areas. A
few models (such as the HRRR) have trended quite a bit wetter/more
impressive with this activity, but consensus across the full model
suite in both placement and QPF remains limited. Have blended in
some slightly higher QPF across roughly the northern half of the CWA
into the Black Hills, but our official forecast remains less than
one-tenth of an inch. Wouldn`t be surprised to see a few isolated
totals reach that 0.10" threshold, especially from the Black Hills
up across the northwestern South Dakota plains, with the driest
conditions across the counties bordering Nebraska.

Another feature we`re noting in today`s guidance is some sort of
secondary cold front/secondary push of cold air advection Thursday
evening into Friday morning. A few models such as the NAM and HRRR
are carrying NW wind gusts of 40 MPH for at least several hours with
this push, while most guidance does more universally show a notable
increase in winds aloft at 700mb (as high as 50kts off the GFS!).
This feature and attendant wind increase is washed out completely by
the various model inputs blended into the NBM, and not every model
brings stronger gusts to the surface. Simulated reflectivity off the
HREF members may be picking up on this feature as well. Confidence
is currently low in how much surface gusts may increase, but this
will be a period we`ll continue to evaluate in future
forecast updates.

Overall forecast confidence Friday through Monday is high with a
general warming/drying trend expected...supported by modest
amplification of a synoptic ridge of high pressure. Near-critical
fire weather conditions will be possible once again for some areas
each day. Confidence starts to waver by Monday night/Tuesday,
however, as multiple organized low pressure features of interest
invade Canada and the western US with large discrepancies across the
long-range deterministic models. A breezier and more active period
precipitation-wise seems possible, likely continuing through the end
of next week.

&&

.AVIATION...(For the 18Z TAFS Through 18Z Friday)
Issued At 1120 AM MDT Thu Mar 26 2026

Overcast conditions with local MVFR/Isold IFR cigs vsbys in light
rain/light snow are expected through 27/02z. Gusty northerly winds
will diminsih this evening. Cigs/vsbys will improve to VFR aft
27/04z as drier air moves into the region.


&&

.FIRE WEATHER...
Issued At 211 PM MDT Wed Mar 25 2026

A combination of record warm temperatures, gusty winds, low relative
humidities, and ongoing drought will continue to support yet another
period of critical fire weather conditions through this evening, and
the ongoing RED FLAG WARNING remains unchanged and in effect through
10 PM across northeast Wyoming, the Black Hills, and portions of
southwestern South Dakota. The strongest winds and lowest RH values
will overlap across southern Campbell and Weston counties in Wyoming
down across Custer and Fall River counties in South Dakota, where a
few stations have already reported wind gusts in excess of 30 MPH
and RH values as low as 14 percent early this afternoon. Winds will
be lighter across the western South Dakota plains, although
occasional gusts greater than 25 MPH are possible during peak
heating this afternoon. Keep in mind that even where humidity values
remain closer to 20 percent, it won`t make any meaningful difference
in the risk of fire spread with extremely dry fuels in place.

Winds shift into the northwest tonight with a much cooler, more
humid airmass in place for Thursday, although NW wind gusts of 20 to
30 MPH are expected much of the day across the region. While
confidence is low, a several hour increase in those gusts is
possible between Thursday evening and Friday morning as a
reinforcing shot of cooler air pushes into the region. The good news
is RH values should bottom out at 30-40 percent Thursday afternoon
despite the breezy conditions. A warming/drying trend returns for
Friday through Monday with afternoon RH values back to 10-20 percent
and afternoon wind gusts potentially approaching 25 MPH at times,
thus another period of near-critical fire weather conditions.

&&

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

$$

UPDATE...JC
DISCUSSION/KEY MESSAGES...KSmith
AVIATION...Hintz
FIRE WEATHER...KSmith