437
FXUS63 KDMX 261121
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
621 AM CDT Wed Aug 26 2026

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

.KEY MESSAGES...

- Breezy winds out of the northwest today with gusts up to 25
  mph. Highs in the 80s through Friday.

- Shower/storm chances return late Friday night into Saturday
  morning with additional chances later in the weekend and into
  early next week.

- Warming temperatures into the weekend with heat indices in
  the 90s on Sunday.

&&

.SHORT TERM /THROUGH THURSDAY NIGHT/...
Issued at 213 AM CDT Wed Aug 26 2026

Meager flow with a subtle reflection of a boundary was evident
across central Iowa overnight. Calm winds were reported over most of
southern Iowa where dew points remained in the 70s. This has allowed
for the development of fog, especially in the Nish Valley. Looking
behind the front, dew points were dropping into the 50s. The front
should sink to the I-80 corridor by morning, the dry air advection
eating into the fog north of it. Areas of fog under 2 miles will be
possible in southern Iowa for the morning commute. It may
potentially be dense (1/4 mi or less) close to the Missouri border
and in the Nish Valley where the winds are lightest. The need for a
Dense Fog Valley will be assessed through the morning. Fog will burn
off and lift to low clouds, these eventually being pushed south with
the front through the morning. We`ll be left with mostly sunny skies
and highs in the low 80s. Northwest winds will increase in the
afternoon with gusts up to 25mph possible north of Highway 20.

Temperatures will be similar on Thursday, but with high pressure
dropping the winds.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Issued at 231 PM CDT Tue Aug 25 2026

The upper ridge starts to move eastward on Friday as the eastern
trough deamplifies flattening out the flow a bit into the weekend.
The surface high pressure also moves off to the east during the
daytime Friday. Several rounds of shortwave energy pass through the
flow with moisture returning late Friday night into Saturday morning
on the nose of the low level jet (overnight Friday night). This will
bring the return of shower and storm chances (20-40%) especially
west/north. Although there will be dry periods, active weather
continues the later part of the weekend into early next week as well
with several additional chances for showers/storms. Temperatures
begin an upward climb again Saturday into Sunday with heat indices
in the 90s on Sunday at this time range.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 617 AM CDT Wed Aug 26 2026

A round of dense fog is likely at KOTM in the immediate term as
Oskaloosa has dropped to 1/4 mile. Satellite has the dense fog
extending up towards I-80 and moving southeast, so have a tempo
group for LIFR and prevailing IFR. A wind shift is ushering in
dry air which may burn off some of the dense fog, hence TEMPO
for dense fog. KOTM remains AMD NOT SKED. MVFR fog will hang on
only briefly for KDSM and become VFR within the first hour.

Terminals north of KDSM will have prevailing VFR through the
period. Gusts to around 20kts possible in the afternoon.

&&

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

&&

$$

SHORT TERM...Jimenez
LONG TERM...05
AVIATION...Jimenez