Storm Lake, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

021
FXUS63 KFSD 290649
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
149 AM CDT Sun Jun 29 2025

.KEY MESSAGES...

- Ongoing thunderstorm activity will continue to bring primary
  hazards of 60-70 mph winds and lesser risks of large hail to
  portions of SE South Dakota, SW Minnesota, and NW Iowa through
  the morning hours.

- Isolated to scattered storms may redevelop later Sunday
  afternoon, mostly south of I-90. However confidence remains
  low on this potential, which may focus more over
  Nebraska/Iowa. Primary hazards would be quarter size hail and
  60 mph winds.

- Dry and only slightly cooler conditions return through
  midweek before our next low end risk for thunderstorms arrive
  Wednesday.

- The 4th of July holiday forecast remains uncertain, but
  potential for thunderstorms remains increased (30 to 40%) for
  Friday into Saturday.


&&

.DISCUSSION...
Issued at 146 AM CDT Sun Jun 29 2025

THIS MORNING:  Broad westerlies continue to push several lobes of
vorticity through the area early this morning.  Ongoing convection
over southwest Minnesota trailing into south central South Dakota
and northern Nebraska will continue to take an east southeast
trajectory over the upcoming 2-4 hours.  While a low end hail risk
will persist, the greatest severe weather potential will likely come
from downburst winds after brief upticks in reflectivity collapse as
effective shear remains rather weak along and south of I-90. The
greatest short term severe weather risk is likely in areas
south of I-90 towards the MO river valley and into far western
Iowa. We`re also keeping a closer eye on two other waves over
western South Dakota that will try to move eastward through mid-
morning Sunday.

SUNDAY:  Additional convection moves east over southern South Dakota
through mid-morning Sunday, though the severe weather risk remains
very uncertain.  While we`ll still be dealing with upwards of 1500
J/KG MUCAPE, low-mid lvl winds remain rather weak, and mid-lvl lapse
rates weakening, which should lower the threat eastward.  Behind
this wave, subsidence may take over though the middle of the day as
the likely poorly defined surface front sinks southward into central
Nebraska into north central Iowa. Convective temps may be reached by
early to mid afternoon over portions of southern Minnesota,
northwest Iowa, and northern Nebraska owing to the development
of widely scattered strong to isolated severe storms mostly
along and southeast of a line from Vermillion to Spencer.
Elsewhere temperatures rise into the low to middle 80s.

SUNDAY NIGHT: Models have congealed towards a solution that
brings another weak shortwave through the Dakotas Sunday night
into Monday. Instability should remain fairly weak, but forcing
with the wave could lead to widely scattered showers and a few
thunderstorms into Monday.

MONDAY-TUESDAY: High pressure moves into the Northern Plains for
Monday and Tuesday, producing high confidence in quiet conditions
and temperatures in the lower to middle 80s Monday, towards the
middle to upper 80s Tuesday.

WEDNESDAY-SATURDAY: Isolated to scattered showers and thunderstorms
may be possible early Wednesday morning on the nose of a seasonally
weak LLJ. Severe storms not anticipated at this time but activity
could linger well into the late morning hours Wednesday.

The forecast remains dry heading into the 4th of July, but
confidence is rising that temperatures will rise into the 90s in
most locations by the 4th.  Broad westerly to southwesterly flow
will again favor increasing PoPs towards the 4th and 5th. Though
shear remains weak, instability should be seasonally high leading to
some increased potential for a few stronger storms for the holiday
activities on the 4th and potentially through the 5th.


&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1209 AM CDT Sun Jun 29 2025

Scattered convection will remain possible through the overnight
hours and into Sunday. In convection, brief visibility drops to
2SM will be possible with MVFR ceilings. Northwest to north wind
gusts to 40 mph may be possible at FSD as convection moves east.

Considerable uncertainty remains on rain changes through Sunday.
If morning convection clears east, then a lull may take place
for scattered afternoon thunderstorms reform.

&&

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

&&

$$

DISCUSSION...Dux
AVIATION...Dux