357
FXUS63 KFSD 090340
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1040 PM CDT Fri May 8 2026

.KEY MESSAGES...

- Near normal temperatures expected this weekend. Outside of
  Saturday morning sprinkles, no rain is anticipated.

- Temperatures begin to warm through the upcoming work week, and
  by the end of the week may be approaching the lower to middle
  80s with outside chances of 90 by the weekend.

- Rain chances for the week ahead will be focused on Monday
  night and again Thursday, though amounts will stay low. Severe
  weather risks also remain low.

&&

.UPDATE...
Issued at 848 PM CDT Fri May 8 2026

Now that we`re starting to lose our diurnal mixing, any elevated
fire concerns are waning this evening. Similar to last night, should
see relative humidity (RH) values gradually recover overnight as
temperatures fall into the mid to upper 40s. Otherwise, we`re still
on track for a few additional sprinkles to light showers as a cold
front tracks through the area to start the day on Saturday. While
mainly light accumulations are expected, some of the 00z high-
resolution guidance is starting to show more coverage than
originally anticipated so slightly tweaked our POPs to get more
coverage in there especially north of I-90. Nonetheless, should see
most of this developing activity exit our region by midday. Lastly,
another round of drier conditions is expected behind the cold front.
As a result, can`t rule out some locally elevated fire concerns in
the afternoon/evening as northerly winds strengthen.

&&

.DISCUSSION...
Issued at 1248 PM CDT Fri May 8 2026

THIS AFTERNOON: A warm, dry, and windy afternoon continues
throughout the forecast area this afternoon. As temperatures
rise into the 70s, we`ll continue to see RH values fall towards
the 20% range. As we reach peak mixing, gusts should begin to
top in the 20 to 30 mph range in the Tri-State area. While RFW
criteria may be met for a couple hours this afternoon, recent
greenup should prevent widespread extreme fire behavior.
Soundings continue to show the very low probability of isolated
showers popping up after 21Z in areas along but mostly southeast
of I-90. Severe storms not expected, but brief 30-40 mph wind
gust may be possible.

TONIGHT:  Winds settle down this evening, but will remain southwest
through the night.  This results in warmer overnight low
temperatures in most locations.

SATURDAY: By daybreak Saturday, confidence remains high that a
weak cold front will settle southward through the area. By 12Z
this front may be just north of I-90 bringing with it a change
to a northerly surface wind, but also a low probability for high
based sprinkles/showers/virga. Once this front clears the area,
temperatures slowly warm back to the mid-60s, with breezy
northerly winds into the early evening.

SUNDAY: Temperatures remain cool on Sunday under the influence of
Canadian high pressure.  With a light north wind continuing, high
temperatures stay in the middle to upper 60s.

MONDAY-WEDNESDAY:  We`ll begin to see a gradual rise in temperatures
as mid-lvl heights rise through the Plains. Despite a breezy
southeast wind Monday afternoon that could lead to elevated fire
danger, high temperatures return to the 70s in most locations with
20-30% probabilities of 80+ degree temperatures in south central SD.
A frontal boundary swings eastward Monday evening and overnight.
MLCAPE profiles suggest some potential for 500-1000 J/KG through
central SODAK, but moisture itself remains very limited and there is
also a bit of capping in place. This should limit the overall
developmental potential of any activity that tries to develop as the
front moves east overnight. Temperatures cool slightly on Tuesday as
low-lvl flow shifts to the northwest. The latest NBM suggests
potential for 30 to 40 mph afternoon wind gusts, which is a signal
within the EC/CMC deterministic and ensemble guidance. The GFS/GEFS
is quite a bit lower, but if these winds do develop, then fire
danger may be quite elevated through the region. Overall
probabilities of exceeding 30 MPH are greater than 80%, with
potential of 40+ mph around 10-20%. Winds again turn to the south on
Wednesday, keeping high temperatures in the middle to upper 70s.

THURSDAY-SATURDAY: While quite a bit of uncertainty remains in the
specifics for the end of the week, overall trends in ensemble data
suggest a warming trend continues into next weekend.  Mid-lvl
heights continue to rise through the end of the week, pushing 850mb
temperatures into the 20C range by Friday.  The presence of several
weak mid-lvl perturbations adds some uncertainty to the forecast in
regards to thunderstorm and cloud potential. This is partially
why the NBM 25/75th percentile temperature spread climb to
nearly 10-15 degrees by Thursday and Friday. However, the broad
synoptic pattern does seem to favor more convection risks
(perhaps even stronger convection) within the region by next
weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1035 PM CDT Fri May 8 2026

Mainly VFR conditions will continue this TAF period. Taking a
look at satellite imagery, mostly clear conditions continue this
evening. However, should see stratus and pockets of sprinkles to
light showers approach from the north with a cold front. With
this in mind, decided to go prevailing -SHRA for all TAF sites
for at least a portion of the TAF period. Nonetheless, any
accumulations should be minimal. Lastly, light southwesterly
winds will become more northerly behind the cold front with
breezier conditions expected during the afternoon hours.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

UPDATE...05
DISCUSSION...Dux
AVIATION...05