Mallard, Iowa Weather Forecast Discussion

916
FXUS63 KDMX 251722
AFDDMX
Area Forecast Discussion
National Weather Service Des Moines IA
1222 PM CDT Thu Sep 25 2025
...Updated for the 18z Aviation Discussion...
.KEY MESSAGES...
- Above normal temperatures and dry Thursday through at least
  early next week.
&&
.DISCUSSION...
Issued at 215 PM CDT Wed Sep 24 2025
Visible satellite imagery early this afternoon shows plenty of
cumulus clouds over the state and these will persist until
shortly after sunset. Forecast soundings show a rather dry
column, but with the steep low level lapse rates and what
moisture there is, it may and has been enough to squeeze out
sprinkles or a fleeting shower over southern Iowa/south of I-80.
This chance of a sprinkle/shower is also shown in a few of the
high resolution models, namely the ARW cores and the HRRR. Any
showers will dissipate quickly after sunset. Into tonight, winds
will become quite light or calm as the boundary layer decouples
and surface high pressure pushes over the state. Moisture
trapped beneath the near surface inversion should result in fog
starting to form a few hours after midnight with the most
widespread fog coverage around sunrise. 12z HREF shows the
highest probability of visibilities under a mile over parts of
northern Iowa with those chances at 40 to 70% depending on the
location. While soundings do show that far south central into
southeast Iowa have lower chances of fog formation, have
broadbrushed the inclusion in the forecast. Areas of fog that do
form will dissipate by around 9am.
The main weather theme Thursday afternoon into early next week will
be mostly dry conditions with temperatures above normal for late
September in the upper 70s or low 80s. This benign pattern is being
drive by a somewhat slowly evolving upper level pattern, which will
see an elongated, positively tilted trough shifting eastward from
the central US leaving behind a closed low over the Deep South by
late this weekend. Upstream of Iowa, a ridge will be advancing
towards the state through the end of the week with another closed
low off the California coast that moves to the Four Corners region
by the end of the weekend. While a shortwave trough will ride
overtop the ridge sending a cold front into the state this weekend,
moisture from the Gulf will still be cut off with the forecast
remaining dry.
&&
.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1222 PM CDT Thu Sep 25 2025
VFR conditions with winds below 10 knots will prevail through
the period at all terminals. FEW to perhaps SCT FL035 have
developed or will develop at ALO/DSM/OTM this afternoon before
dissipating this evening. There may be a touch of high level
smoke overhead, but not enough to include anything prevailing.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
DISCUSSION...Ansorge
AVIATION...Ansorge

NWS DMX Office Area Forecast Discussion