633
FXUS63 KUNR 041115
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
515 AM MDT Fri Apr 4 2025

.KEY MESSAGES...

- A weak system will bring chances for light rain and snow through
  this morning and early afternoon

- Warmer and drier pattern setting up for later this weekend into
  next week

&&

.DISCUSSION...(Today Through Thursday)
Issued at 307 AM MDT Fri Apr 4 2025

At this hour, current radar imagery shows a band of light to
moderate precip (mostly snow) associated with a cold front pushing
through northwestern SD. Meanwhile rain associated with an upper
level disturbance is moving northward into south central SD. These
systems will continue to converge through this morning and push
eastward with rain transitioning to snow as colder air moves into
the region. With the front moving faster than earlier model runs
have depicted, precip will end earlier across the CWA, tapering
off from west to east through this afternoon and being out of the
CWA by this evening. A few snow showers may form across the
southern hills convergence zone this afternoon as northerly winds
pick up behind the front. Snow accumulations expected to be minor
to light across much of the area with the northern slopes of the
northern Black Hills picking up an 1-2 inches this morning thanks
to upslope enhancement.

As for the winds, deterministic guidance depicts modest 3 hr
pressure rises of 3-4 mb behind the front this morning, which
should facilitate gusty north winds - especially across the
western SD plains. While much of the western SD plains may see
gusts of 30 to 40 mph this morning and afternoon, not anticipating
wind gusts to exceed 45 mph (0% probs per HREF grand ensemble),
precluding the need for any wind headlines today. With the light
accumulations, widespread blowing snow isn`t a concern but
visibilities may drop in the heavier bands of snow this morning.

As the upper level trough pushes east through Saturday, upper
level ridging builds over the west, bringing drier and warmer
conditions to the region. Deterministic model runs show 850 mb
temps steadily increasing through this weekend into next week,
rising to 5-10C by Monday/Tuesday. This will support sfc temps in
the 50s to low 60s. The next chances for precip look to be towards
the mid-week in the Tues/Wed timeframe as a shortwave crosses the
Northern Plains.

&&

.AVIATION...(For the 12Z TAFS Through 12Z Saturday Morning)
Issued At 512 AM MDT Fri Apr 4 2025

A cold front continues to push through the area. As the front
pushes through, snow (with some rain across south-central) will
continue to push off to the southeast, with IFR/LIFR conditions.
Precipitation will taper off from northwest to southeast after
13-15z this morning, pushing out of the forecast area after 22-00z
this afternoon with VFR conditions returning. Gusty NW winds will
persist behind the front, with gusts to 35kt possible.

&&

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

$$

DISCUSSION/KEY MESSAGES...Wong
AVIATION...SE