Weather alerts for the NWS Des Moines IA forecast area

000
FXUS63 KDMX 281131
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
631 AM CDT Wed Oct 28 2026

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

- Patchy to locally dense fog ongoing across northern and west
  central Iowa. This is expected to burn off after sunrise.

- Low shower chances through the early part of the day before 
  more widespread strong to severe thunderstorms develop later 
  today into the overnight. There is a Marginal (Level 1 of 5) 
  Risk for severe weather.

- Widespread rain chances move back into Iowa later Thursday
  night into Friday and Saturday leading to mild and perhaps 
  damp conditions for trick-or-treating. Rumbles of thunder also
  possible on Friday.

- Temperatures remain seasonal if not above normal through the
  next week.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 229 AM CDT Wed Oct 28 2026

Patchy to locally dense fog is ongoing across parts of west-central 
and northern Iowa. A look around various webcams show isolated 
pockets of poor visibility around Mason City, with less impacts to 
visibility elsewhere in places like Denison, Fort Dodge, and Algona. 
All of this jives with the visibilities being reported on METARs. A 
complexifying factor with this is that the fog is in a relatively 
narrow ribbon of higher dewpoints ahead of an area of stratus. 
Regardless, the fog is expected to burn off after sunrise this 
morning.

Other notable conditions around the state include that we are in 
southerly flow, which is going to aid in warming the state up to 
much above-normal temperatures through the day before a cold front 
sweeps through closer to sunset - more on that later. The southerly 
flow is noted both at the surface and at 850mb (albeit, with a slight 
southeasterly component to it), which leads to decent moisture 
transport into the region. Up at 500mb, flow is a lot more easterly, 
leading to less moisture transport in the upper levels. Also noted 
at 500mb is a fairly potent shortwave that will move through the 
region, which is the feature tied to the aforementioned cold front. 
While the impacts of the shortwave will be a little spicier north of 
Iowa where the parameter space is better, strong to severe 
thunderstorms will still be able to form across portions of western 
and northern Iowa later today. Additionally, ahead of any convective 
activity, a tightened pressure gradient will lead to breezy winds 
gusting as high as 30mph at times throughout the state.

As far as the expectations for any severe weather, sounding profiles 
around Iowa show that capping could be an issue, with the 00z HRRR 
and NAM showing a mid-level cap at around Algona and Estherville, 
while at sites farther south and west (i.e. Fort Dodge, Mason City, 
and Iowa Falls), mid-level capping is not as much of an issue. The 
other elephant in the room demanding to be addressed is CAPE. 
Aforementioned sounding profiles show fairly skinny CAPE profiles, 
especially farther to the east. This, combined with a low freezing 
level (~8500ft) and dry air in the mid- to upper-level will support 
decent hail growth with more robust updrafts. The drier air will 
also aid in the potential for severe wind gusts. At the same time, 
lapse rates look fairly low, at around 6.5 degC/km across the 
state which will help balance how widespread severe storms are 
able to be. Finally, while there is plenty of low-level turning,
capping will keep storms in check across Iowa, making it very 
difficult for surface-based convection in the area.

As the cold front moves through, it should be clear of the area 
around or just after midnight, signaling the end of this round of 
showers and storms. Thursday looks to be largely with temperatures 
still above normal for this time of year. High pressure will attempt 
to set up across MN/WI which will influence much of Iowa leading to 
light winds and calm conditions with fairly clear skies. The next 
system that will impact the area looks to arrive Thursday night into 
Friday as another low lifts into the area from the south.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 246 PM CDT Tue Oct 27 2026

While it will not rain continuously, showers are expected from 
Friday through a good portion of Saturday across many portions of 
Iowa with peals of thunder likely on Friday as well. There is 
variability in the models whether this rain will last all the 
way through Saturday or if Saturday starts to turn drier or if 
Sunday morning will have lingering showers as well. Regardless, 
trick or treaters will encounter mild conditions and perhaps 
damp ones as well Friday or Saturday evening depending on when
the festivities are held. Quickly following this southern 
stream wave will be a more pronounced mid-level trough or closed
low that will push over the Rockies by the start of next week
and into the central part of the country by the middle of next 
week. While there is uncertainty in the exact mid-level pattern
evolution early next week, confidence is increasing in another 
round of showers and thunderstorms in this timeframe. With this 
being one of several rounds of rainfall spread out over the next
week with total rainfall between 1.5 and 2.5 inches over the 
state from the grand ensemble, some within bank rises are
possible on mainly smaller streams and tributaries to the larger
rivers according to recent runs of the National Water Model 
forced by the NBM and GFS.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 631 AM CDT Wed Oct 28 2026

Isolated showers are moving across Iowa this morning, with a
small cluster near KMCW at 1130z. These will be around
through the morning but should miss most TAF sites due to their
widely scattered nature. South winds become breezy this
afternoon at 10-15 kts with gusts of 20-25 kts. A front moves
across Iowa from NW to SE through the evening with a line of
storms expected as it moves across. KFOD/KMCW will be impacted
first around 00z with -TSRA. The line weakens as it moves SE 
and included prevailing -SHRA at KDSM/KALO with prob30 for 
thunder. The line reaches KOTM by 06z but should be diminishing,
so only included -SHRA at this time. Winds shift to out of the 
north west, then north, behind the front. 

&&

.DMX WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SHORT TERM...67
LONG TERM...Ansorge
AVIATION...Hagenhoff