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000
FXUS63 KFSD 221720
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1220 PM CDT Mon Apr 22 2024

.KEY MESSAGES...

- A Wind Advisory has been issued for locations along and east of a
Windom, MN to Canton, SD, to Yankton, SD line. Gusts up to around 45
mph are expected.

- Periods of elevated fire danger are possible today and Tuesday
where vegetation has not yet greened-up sufficiently.

- Showers and sprinkles are possible this afternoon and again
Tuesday afternoon, mainly near and east of I-29. Any rain amounts
will be minimal.

- Frost will be possible Wednesday morning with widespread low
temperatures in the 30s.

- Chances for rain arrive later Thursday into Friday and again later
over the weekend. There is a small chance of a few strong to severe
storms during this period as well.

&&

.DISCUSSION...
Issued at 353 AM CDT Mon Apr 22 2024

High level cirrus continues to push in aloft early this morning
ahead of an incoming upper level wave. This has held temperatures on
the warm side as temperatures remain in the 30s and 40s to even a
few spots remaining at 50 degrees F. Temperatures should still fall
a bit more down to the upper 30s to mid to upper 40s by sunrise. As
the sun begins to rise, mixing will quickly increase and lead to
strong southerly wind gusts east of I-29. These gusts are expected
reach up to around 45 mph but will be on a slow, downward trend
through the morning and early afternoon hours. As such, have decided
to issue a Wind Advisory for locations along and east of a Windom,
MN to Canton, SD, to Yankton, SD line. The Wind Advisory is in
effect from 9 am to 4 pm today. A cold front tied to the previously
mentioned upper wave will push through the area throughout the day
today. As the front moves through, strong southerly winds will
briefly diminish and then restrengthen out of the northwest. Gusts
up to around 35 mph are expected but stronger gusts are possible as
BUFKIT soundings show that there is little to no inversion at the
top of the mixed layer. The other aspect to this afternoon is
decreasing humidity behind the front. High temperatures will warm to
60s and 70s as the cold front pushes through. Dew points will jump a
bit up to the upper 30s to low 40s just ahead of the front but will
drop to the 20s and 30s behind the front. This will result in low
relative humidity (RH) values down to the 20-30% this afternoon,
lowest west of Windom, MN to Canton, SD, to Yankton, SD line.
Despite winds and RH meeting critical fire danger criteria, have
decided to not issue any fire related headlines as fuels have been
greening across the area. With moistening fuels in place, fire
danger will only be moderate to high this afternoon. The cold front
coming through will also spark a few light showers east of I-29 this
afternoon. Have kept a 15-25% chance for light rain showers in this
area along with keeping a mention of sprinkles. Rainfall
accumulations are expected to be minimal. Strong winds and rain
chances will come to an end during the evening hours. Low
temperatures will fall to 40s tonight.

Tuesday will continue to see gusty winds across the area as a cold
advective northwest flow regime remains locked over the area as the
base of the upper level wave pushes through the Northern Plains.
Northwest winds will continue to gust up to 30-40 mph. High
temperatures will be a bit cooler, only warming to the mid 50s to
mid 60s as 850 mb temperatures will reside to either side of 0
degrees C. With cooler temperatures in place along with slightly
higher dew points, RH will only fall to 30-45% along with moist
fuels in place. This will result in moderate fire danger across the
area. Wind will wane through the evening hours as a surface high
pressure system moves into the area. Overnight low temperatures will
fall to the cooler wise of things, down to the low to mid 30s. With
low temperatures approaching freezing, frost is possible.

Wednesday will be a quiet day with high pressure sliding through the
area. Light to marginally breezy winds are expected along with high
temperatures in the 60s and lows down to the 40s.

A stronger upper level wave begin to eject into the Plains on
Thursday. Warm southerly flow out ahead of the wave will push high
temperatures back into the upper 60s and 70s. Rain chances will
increase during the evening hours as warm air advection (WAA)
strengthens out ahead of the wave. Soundings do show some elevated
instability for overnight Thursday so elevated storms may be
possible. Low temperatures will only fall to the 50s thanks to the
WAA in place.

Friday has the highest potential for seeing storms across the area.
Some of these storms may have the potential to be severe if all the
ingredients come together. Medium range varies on how the
previously mentioned ejecting wave into the Plains will evolve. The
Canadian and Euro are further north and slower with the wave while
the GFS is faster and farther south with the wave. These trends are
also reflected in their ensemble counterparts. However, turning to
ensemble clustering reveals that the most favored cluster has a
further north and slower trough ejection, signaling the potential
for some strong to severe storms. Too early to say for sure of any
specific hazards at this point but will continue to keep an eye on
this system over the coming days.

Rain chances look to continue through the weekend as an active
pattern sets up aloft. Medium range guidance depicts another wave
ejecting into the Plains but show a large variance in the evolution
of this wave. Despite the models differences, chances for rain will
persist through the weekend.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1218 PM CDT Mon Apr 22 2024

VFR conditions will continue during this TAF period. Taking a
look at satellite imagery, upper level cirrus and some
altostratus continue to push across the area ahead of a cold
front along with a few embedded showers. While accumulations are
expected to be fairly limited due to dry air, coverage will
likely increase east of I-29 this afternoon and evening as the
LLJ continues overhead. Otherwise, breezy southwesterly winds
will shift back to the northwest this evening and gradually
diminish over areas south of I-90 overnight.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory until 4 PM CDT this afternoon for SDZ070-071.
MN...Wind Advisory until 4 PM CDT this afternoon for MNZ081-090.
IA...Wind Advisory until 4 PM CDT this afternoon for IAZ002-003-
     012>014-020>022-031-032.
NE...Wind Advisory until 4 PM CDT this afternoon for NEZ013-014.

&&

$$

DISCUSSION...Meyers
AVIATION...Gumbs