Moneta, Iowa Weather Forecast Discussion

358
FXUS63 KFSD 191950
AFDFSD
Area Forecast Discussion
National Weather Service Sioux Falls SD
250 PM CDT Fri Sep 19 2025
.KEY MESSAGES...
- Scattered showers and very isolated thunderstorms continue
  this afternoon. A very low chance of a weak funnel or two is
  possible across parts of southwest Minnesota.
- Temperatures warm slightly Sunday, bringing a risk for a few
  late day and nighttime thunderstorms. Severe weather risks
  remain low at this time.
- Chances for rain persist through the beginning of next week.
  The highest chances for rain will come south of I-90 though
  details can change over the next few days.
&&
.DISCUSSION...
Issued at 249 PM CDT Fri Sep 19 2025
Nearly vertically stacked low pressure continues to spin over the
area this afternoon. Northwesterly flow on its backside has kept
stratus blanketed across most of the area. This should keep rain
chances tied to light showers that develop beneath the stratus for
the rest of this afternoon and evening. The exception is portions of
southwest Minnesota which could see some slightly stronger showers
or weak storms IF breaks in the stratus can occur. While severe
storms are not expected, an isolated funnel or two is possible in
this area due to weak surface convergence along a surface boundary.
The enhanced stretching potential shows elevated values along with
the non-supercell tornado parameter showing a value up to 1, thus
weakly supporting this potential. The stratus looks to persist
across the majority of the area tonight. This will continue
drizzle/light rain chances for the overnight hours as well as a low
(20-30%) chance for patchy fog. Low temperatures are expected to
cool to the 50s tonight, though wouldn`t be surprised to see lows
only fall to the low 60s given the cloud cover in place.
The low pressure system will meander a bit more to the northeast on
Saturday. This will result in continued low level stratus and light
rain showers across the area. As of now, light rain showers are
expected mainly east of I-29. Just like today, rainfall amounts will
be quite light at a few hundredths to up to a tenth or two at the
most. High temperatures will remain near seasonable in the upper 60s
to low 70s. The low pressure system will finally wrap up to the
north of the area on Sunday. This will keep the main synoptic ascent
north and east of the forecast area. That said, a warm front will be
draped across part of the area at the surface. The location of this
front is a bit uncertain at this time but it could serve as a focal
point for initiating showers and storms. As of now, large scale
descent will be in place with only weak warm air advection (WAA) in
the low levels. Steepening mid level lapse rates thanks to the low
level WAA may result in instability values on the order of about
1,000 J/kg. At the same time, this WAA will result in a small cap.
If any storm was to break the cap, it would be during the late
afternoon to early evening hours. Still quite uncertain though given
the weak forcing in place. This uncertainty keeps severe storm
chances low at this time. Otherwise, Sunday will be a bit warmer
with highs in the mid to upper 70s to low 80s.
Rain chances look to persist into early next week as weak shortwaves
pass through the upper level flow. One shortwave could bring chances
for showers and storms with it Monday evening as this wave interacts
with the previously mentioned warm front. Sufficient instability
looks to be in place but vertical shear looks quite weak, even with
the locally slight increase in shear with this shortwave
approaching. The ensembles show a bit of a messy perspective but
generally show a 20-40% chance for exceeding a tenth of an inch of
rain south of I-90. Medium range guidance is in modest agreement in
a stronger shortwave trough passing near the area on Tuesday. This
could result in additional chances for showers and storms if this
wave passes through the forecast area. Tough to say at this point
but the ensembles again show a 20-50% chance for rainfall total to
exceed a tenth of an inch south of I-90 and especially south of
highway-20. Will keep an eye on this potential over the next few
days. Aside from rain chances, highs on Monday and Tuesday will
remain in the 70s to low 80s.
After this wave pushes through, the middle and end of next week
looks to be on the quiet side. The ensembles are in generally pretty
good agreement this far out. The agreement shows the forecast area
residing downstream of an upper level ridge. At the surface, they
show surface ridging to the northeast of the area with surface low
pressure across parts of the lower Midwest states. This will promote
easterly flow and dry conditions to end the week. High will remain
in the 70s, making for a nice way to end the work week.
&&
.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1237 PM CDT Fri Sep 19 2025
Latest satellite imagery shows low level stratus blanketing the vast
majority of the area. The stratus is sitting at MVFR/IFR levels
while visibilities remain largely VFR. Light rain is falling beneath
the stratus, most notably across portions of southwest Minnesota and
parts of northwest Iowa. With low pressure just north of the area,
think that the MVFR/IFR stratus will continue to sit over the area
for the rest of today. Trends will be monitored though. Ceilings may
lower back to LIFR levels tonight but confidence is not high enough
to include in a TAF at this time. Patchy fog is also possible
beneath the stratus as well, though again, confidence is not high
enough to include in a TAF at this time. The stratus and light to
very light rain showers will persist through the overnight hours
before ceilings lift back to MVFR levels to end the period. &&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Meyers
AVIATION...Meyers

NWS FSD Office Area Forecast Discussion