774
FXUS63 KUNR 182023
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
223 PM MDT Fri Apr 18 2025

.KEY MESSAGES...

- Areas of precipitation will diminish this evening

- Warming temperatures and dry through the weekend

- Active pattern will bring precipitation chances through next
  week


&&

.DISCUSSION...(This Evening Through Friday)
Issued at 159 PM MDT Fri Apr 18 2025

Current Water Vapor and upper air models show trough extending
from the northern plains down into southern NV/UT, upper ridge
building over the PAC NW. Surface chart depicts high pressure over
southwestern MT, with low to our east. Radar has isolated
precipitation over parts of the Black Hills and southwestern SD.
Plains areas receiving precipitation are generally seeing rain,
while parts of the Black Hills have seen some light snow
accumulations. Winds are currently breezy out of the northwest
with temperatures in the 30s and 40s.

Isolated rain/snow will diminish this evening and dry/warming
conditions are expected the rest of the weekend as the upper
ridge slides over the Rockies into the plains. Low level WAA will
bring temperatures into the upper 50s and low 60s for Saturday.
This dry air will allow for elevated fire conditions as RH values
drop into the upper teens for parts of northwestern SD down into
central SD. Shortwave swings into the northern and central plains
on Sunday, however models keep the bulk of the forcing and
moisture to the south of the FA. Last couple model runs have been
in agreement showing the better chance for precipitation coming
around Monday/Tuesday as upper trough swings over the northern
Rockies into the region. Warmer temperatures will likely mean bulk
of precipitation will be rain, except for higher elevation Black
Hills areas with some light snow or a mix. Models diverge the
latter half of the week, with some deterministics pointing towards
a dry and warming trend, and others showing more unsettled active
flow.



&&

.AVIATION...(For the 18Z TAFS Through 18Z Saturday)
Issued At 1102 AM MDT Fri Apr 18 2025

Areas of MVFR/IFR conditions will persist across the area today,
especially from northeast WY to the Black Hills and southern SD.
Chances for snow showers can be expected across most of the area,
becoming rain and snow showers this afternoon. Conditions will
gradually improve late today and this evening, with VFR
conditions expected later tonight through Saturday

&&

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

$$

DISCUSSION/KEY MESSAGES...Dye
AVIATION...13