095
FXUS63 KFSD 060142
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
842 PM CDT Fri Jun 5 2026

.KEY MESSAGES...

- Warm conditions Saturday with highs in the upper 80s and low
  90s. Southeast winds will be breezy, gusting 25-35 mph over
  central South dakota and decreasing as you move east.

- Low chances (<25%) for showers and thunderstorms along and
  south of Highway 20 Saturday evening and overnight.

- A system wraps north Sunday into Monday and will bring
  scattered showers and thunderstorms to the area. Severe
  weather chances are currently low.

- Temperatures heat up this weekend into next week. There is an
  increasing chance (30-70%) of highs exceeding 95 degrees
  mainly near and west of the James River by Tuesday and
  especially Wednesday. Be prepared to enact any heat related
  safety measures.

&&

.UPDATE...
Issued at 841 PM CDT Fri Jun 5 2026

Mostly clear skies along with light and variable winds will allow
for good radiational cooling tonight. Patchy dense fog is possible
as a result. The most likely areas to see fog are near and east of
Highway 81, and along the James River Valley. As you make your way
early Saturday morning, please ensure you are prepared for changing
driving conditions. Fog should burn off by mid-morning.

For the rest of Saturday mostly clear skies will prevail as highs
climb into the upper 80s and low 90s. For reference, average high
temperatures for early June are in the mid to upper 70s. However, we
will still be ten or more degrees off from breaking any high
temperature records. Overnight lows will be warm in the mid to upper
60s.

A lee trough develops late Saturday afternoon over eastern Montana,
Wyoming, and Colorado. As this pushes east the SPG will tighten and
the LLJ will intensify. Southeast winds are well aligned from the
surface through the 800-750 mb layer. Good mixing will tap into the
LLJ and we can expect increasing wind gusts at the surface. The
strongest winds will be for areas west of Highway 81, where 25-35
mph gusts are possible. East of there to I-29 gusts of 15-25 mph are
expected, and east of I-29 gusts will be around 15 mph or less.
Winds will remain on the gusty side overnight as cyclogenesis
slowly begins to work its way east.

A warm front associated with this feature will drape from eastern
Wyoming, through western South Dakota and southeast into Nebraska
and southern Iowa. As an upper shortwave works through the pattern
the front will move north into southeastern South Dakota. As it does
so low chances (<25%) for isolated showers and thunderstorms are
possible Saturday evening and overnight for areas along and south of
Highway 20. Moderate instability of 1000-1500 J/kg will be present,
but lapse rates of less than 6 deg C/km and 0-6 km bulk shear of
less than 20 kts are not supportive of severe weather. However, some
thunderstorms could still produce wind gusts of 45 mph. Showers may
linger into Sunday morning. As far as totals are concerned, they
should be very light. Ensemble guidance indicates only around a 35%
probability of measurable rain (0.01").

&&

.DISCUSSION...
Issued at 245 PM CDT Fri Jun 5 2026

Storms have developed over far western Minnesota and are
moving east-southeast this afternoon. This activity is associated
with an upper wave that will be moving across the northern Midwest
into the Great Lakes region through tonight. With the better upper
level support off to our northeast, the chance for thunderstorms is
low and the chance for severe weather is even lower in our southwest
Minnesota counties. If a storm were to sneak in (<20% chance), then
it will have around 1,000 to 1,500 J/kg of MLCAPE and around 35-40
kts of shear to work with, which could support an isolated 60 mph
wind gust or instance of half dollar hail. The main time frame for
this highly conditional threat is through 9-10 pm.

Otherwise, tonight will feature mainly clear skies with calm
winds, and thus patchy fog will be possible in spots. The NBM
favors areas near and east of I-29 for fog while the REFS favors
north of I-90. Would lean towards REFS on this one as there is
plenty of moisture north of I-90 left behind from recent
thunderstorms and these areas will cool the fastest towards the
dew point tonight. Clouds may also linger longer near and south
of Highway 20 as well tonight associated with storms to our
south, so this could limit fog potential there. Speaking of
those storms, they look to develop over eastern Nebraska and
southwestern Iowa through the evening hours, but this is
expected to remain south of the area through tonight. One thing
worth watching with these storms is any potential outflow
boundaries that are left behind that could affect weather for
Saturday. Some CAMs including the 05.12Z HRRR and RRFS-2 show
some storms developing over the Highway-20 corridor tomorrow
afternoon and evening, perhaps associated with one of these
potential boundaries lifting northward into our area, so that
will be something to watch. But when looking at overall chances
according to the REFS and HREF, the chance of rain is less than
20%. So otherwise, dry, sunny, and very warm weather is
expected on Saturday, and with ridging aloft, look for highs in
the upper 80s to lower 90s, hottest along the Missouri River
Valley.

On Sunday, guidance shows and upper low moving north across the
central Plains. To the west, a surface low will drag a cold
front into western South Dakota. The EC Ensemble shows an up to
60% chance of measurable precipitation as early as Sunday
morning over northwest Iowa associated with aforementioned upper
low but most other guidance brings better rain chances into the
afternoon. Cloud cover ahead of this system will mean poor
destabilization ahead of any thunderstorms over northwest Iowa,
so the severe weather threat potential looks low at this time.
The cold front off to our west will help fire off strong to
severe storms over the northern High Plains Sunday
afternoon/evening, and some of these will try to push into areas
west of I-29 into early Monday morning. However, waning
instability and storms potentially outrunning the best shear
will mean the chances for severe weather locally with this is
also fairly low at this time.

The main story heading into the next work week will be the
building heat, starting Tuesday. That`s when highs look to climb
into the 90s area-wide, with the potential for highs nearing
100 along the Missouri River Valley. Then Wednesday may be even
hotter as a front turns winds more southwesterly in south-
central South Dakota. The NBM has come down a little bit in
temperatures, but looking at the LREF, it has a 30-50% chance of
highs above 95 in south-central South Dakota and then a 40-70%
chance on Wednesday in that area. One limiting factor to this
heat being realized on Wednesday is that storms may form along
and ahead of the front and so that could affect heating. Either
way, keep up to date with the latest forecast and be prepared to
take heat related safety measures!

&&

.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 618 PM CDT Fri Jun 5 2026

VFR conditions are expected to prevail this period. Scattered clouds
will become clear skies and winds will become light and variable. As
a result, patchy dense fog may form across the region. Though the
best chances look to be near and east of I-29. Fog should burn off
by mid-morning.

Winds will become southeast through the morning and increase. Areas
west of I-29 will see gusts ranging from 15 kts to 28 kts, with the
strongest over south central South Dakota. East of I-29 gusts will
be less than 15 kts. Gusty winds continue through the end of the
period.

&&

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

&&

$$

UPDATE...AJP
DISCUSSION...Samet
AVIATION...AJP