Area Forecast Discussion
Issued by NWS Rapid City, SD

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000
FXUS63 KUNR 130510
AFDUNR

Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
1110 PM MDT Tue Mar 12 2024

.KEY MESSAGES...
1254 PM MDT Tue Mar 12 2024

- Splitting upper trof brings precipitation as well as cooler and
  windy weather for Wednesday and Thursday

- Some snow accumulation expected in the Black Hills and higher
  elevations of northeast Wyoming

- Modified arctic front moves into the Northern Plains/Upper
  Midwest over the weekend with a glancing blow to our area

&&

.DISCUSSION...(This Evening Through Tuesday)
Issued at 1254 PM MDT Tue Mar 12 2024

Water vapor shows upper trof digging through the northwestern
CONUS. At the surface, frontal boundary bisects our zones with a
weak low along the front over far western SD. Early afternoon
temps are in the 50s/60s with cirrus streaming overhead.

Upper trof will continue to dig across the western CONUS tonight
while splitting. Main upper low will gradually form over the
Desert Southwest Wednesday and stall out for several days, while
the northern stream trof works slowly through the Northern Plains
late week. A lead short wave will cross the Central Rockies
tonight into Wednesday and push through the Central Plains on
Thursday. Light rain will become more likely on Wednesday in our
southwestern zones and gradually spread northeast Wednesday night
into Thursday before ending Thursday night or early Friday. While
the best lift/moisture is expected to remain to our south, some
beneficial moisture is likely in our southern half of zones. NBM
probs for at least 0.25 inches liquid are in the 20-40 percent
near and south of I-90, and closer to 50 percent across far
southern portions of northeastern WY and along the NEB border.
However, there is a good chance for a slightly higher bullseye of
precip in the Northern Black Hills/foothills due to upslope flow.
Accumulating snowfall will mainly be limited to the Black Hills
and northeast WY. NBM probs for an inch or more of snow are
generally greater than 50% across the higher elevations of the
Black Hills as well as far southwest Campbell county near Pine
Tree Junction. Probs greater than 4 inches are generally in the
15-30 percent range, but some of the higher resolution solutions
are suggesting higher amounts could creep into southern Campbell
county. Will need to see if those trends for higher amounts
continue.

Northerly winds will become quite breezy Wednesday afternoon as
surface low deepens over the Central Plains, and could approach
advisory levels on Thursday as the surface low ejects
northeastward. Gradually cooling temps can be expected through
Thursday.

Drier and slightly warmer air moves back in on Friday, but an
upper trof will dive into the Upper Midwest/Great Lakes over the
weekend. A modified arctic blast is expected with this upper trof,
but the main brunt of cold air should remain to our east with only
a glancing below for our area. Little to no precip is expected
across our area with this upper trof. Sunday will likely be the
chilliest day, with a warming trend for early next week.

&&

.AVIATION...(For the 06Z TAFS Through 06Z Wednesday Night)
Issued At 1110 PM MDT Tue Mar 12 2024

MVFR/IFR conditions will gradually develop from northwest to
southeast across mainly northeast WY, the Black Hills, and
southwest SD late tonight and Wednesday. Areas of light rain will
also develop across most of these areas, with some snow likely
across the higher elevations of northeast WY and into the Black
Hills, especially Wednesday afternoon and night.

&&

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

$$

DISCUSSION/KEY MESSAGES...Johnson
AVIATION...26


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