FXUS63 KUNR 151112
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
512 AM MDT Wed Apr 15 2026

.KEY MESSAGES...

- Elevated to near-critical fire weather conditions Wednesday and
  Thursday; a Fire Weather Watch is in effect Thursday.

- Cooler with rain/snow behind cold front late Thursday through
  Friday.

- Trending warmer Saturday through early next week.

&&

.DISCUSSION...(This Evening Through Tuesday)
Issued at 1256 PM MDT Tue Apr 14 2026

Active southwesterly flow continues across the central US. Water
vapor imagery shows a shortwave trough pushing through the
Northern Plains and an upper low ejecting out of the Central
Rockies along with an active southern stream as moisture streams
into the Southern Plains. Surface low pressure is centered over
southeastern NE with a weak gradient over the forecast area. Light
showers/sprinkles continue across southwestern SD into south-
central SD, although a dry boundary layer and lack of appreciable
mid-level moisture will limit precipitation amounts. Showers will
taper off this afternoon and early evening as subsidence
overspreads the region.

Warmer and dry tomorrow with temperatures in the upper 60s to upper
70s across the plains. Elevated to near-critical fire weather
conditions are expected with RH falling into the teens to low 20s,
particularly portions of NE WY and SW SD, although there is some
uncertainty regarding boundary layer winds/if frequent gusts > 25
mph will develop. Even warmer (along and south of I90 in SD) and
drier Thursday ahead of a cold front with critical conditions
possible; a Fire Weather Watch is in effect from the Weston County
plains through southern SD.

Cold front arrives Thursday evening bringing cooler air and
potential for rain and snow. Upper trough will eject out of the
Central Rockies, although recent guidance shows split flow
developing. Pacific moisture advects into the region ahead of this
trough, although appreciable moisture is lacking (precipitable
water values ~100-125% of normal). Best chance of measurable
precipitation across NE WY and the northern Black Hills (NBM prob
QPF >0.25" ~30-55%).

Warm air advection returns Saturday with temperatures trending
warmer through the weekend into early next week with elevated fire
weather conditions expected.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Thursday Morning)
Issued At 508 AM MDT Wed Apr 15 2026

VFR conditions are expected through the TAF period.

&&

.FIRE WEATHER...
Issued At 509 AM MDT Wed Apr 15 2026

Elevated fire weather conditions expected today across much of
the area as RH falls into the teens to low 20s. Best overlap of
low RH and stronger winds forecast across southern Campbell and
Weston Counties in WY through southwestern SD. Conditions should
remain below thresholds for any fire weather highlights today.

A Fire Weather Watch is in effect Thursday for the Weston County
plains through southern SD as stronger southwest winds will develop
ahead of a cold front. Daytime minimum RH will fall as low as 12-14
percent Thursday. Mid-level clouds ahead of the front and spotty
high-based showers may complicate things Thursday by keeping
temperatures a bit cooler and RH higher. However, plan for at least
elevated to near-critical conditions Thursday.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...Fire Weather Watch from Thursday afternoon through Thursday
     evening for SDZ321-322-325-326-332>335.
WY...Fire Weather Watch from Thursday afternoon through Thursday
     evening for WYZ317.
&&

$$

AVIATION...15
FIRE WEATHER...15