141
FXUS63 KDMX 221914
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
214 PM CDT Wed Jul 22 2026

.KEY MESSAGES...

- Cooler temperatures will be in place through the work week
  before another warmup this weekend.

- Showers and storms are in the forecast Thursday evening into
  Friday morning. Rainfall totals from 0.5-1 inch with locally
  higher amounts are expected in southwest Iowa.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 210 PM CDT Wed Jul 22 2026

Northwest mid level flow continues today with the ridge positioned
far enough south and west to allow an extended period of cooler
weather. Enhanced flow riding the ridge has brought in additional
cloud cover as well, which should help to limit high temperatures
this afternoon. A few showers have formed over eastern Nebraska and
will attempt to work their way into our southwestern counties.
However, HRRR profiles this afternoon show a deep layer of dry air,
extending from the surface to 600mb, which will be quite an odyssey
for any raindrops hoping to reach the surface. Some returns may show
up on radar this afternoon, but these will mostly evaporate before
reaching the ground. Instability will be basically zero and chances
for thunder will be low. All that to say today will be an incredible
day to be outdoors across Iowa, with mild temperatures, light
breeze, and partly cloudy skies.

Thursday will again be mild as the surface high pressure continues
to sit over Iowa. There may be enough sunshine in the morning and
early afternoon to warm up a bit more than today, and perhaps hit 80
in a few locations. More impactful rain chances are forecast for
Thursday evening into Friday morning. Another shortwave rounds the
top of the ridge and provides the ascent needed for an extended
period of showers and storms. A deep layer of saturation in the mid
levels will form during the evening, and the strengthening nocturnal
LLJ over eastern Nebraska and southwest Iowa will help to replace
our low level dry air in place today with a moist gulf airmass.
PWATs over 2" and warm cloud depths from 4000-4500 will likely be in
place over western and southern Iowa during the overnight hours into
Friday morning. So, while not talking about strong thunderstorms
(MUCAPE is minimal), these showers and storms will be efficient rain
producers. Taylor county, for example, has a NBM mean/90th QPF of
1.2"/3.0". REFS is notably lower with 0.3"/1.2". WPC is
observing a similar trend and outlined southwest Iowa in a
slight risk ERO for the Thursday overnight period. This rain
will fall over areas with mature crops and dry soil, so overall
flash flooding risk is low. However, high-end scenario rainfall
amounts in an urban area would pose a flash flooding risk. In
summary, widespread rainfall appears likely, but there is
significant uncertainty in expected totals, and flash flooding
risk is low but possible.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Issued at 210 PM CDT Wed Jul 22 2026

Ensembles continue to suggest the central Plains ridge strengthens
and advances eastward on Saturday. This will bring in heat by
Saturday afternoon, and even warmer temperatures Sunday.
Temperatures near 90 appear likely Saturday, and perhaps mid 90s by
Sunday. Tropical storm Bertha will be nothing more than a breeze by
the weekend and should allow for an open gulf moisture stream.
Evapotranspiration is also near its peak at this point in the
summer. At this time, it looks like dewpoints will rise to at least
the mid 70s. This would adjust apparent temps up by several degrees
and give us potential for 100+ heat indices Saturday through Monday
in some locations. The position of the ridge and fairly strong mid-
level flow Sunday into early-week will put our area in ring of fire
position with potential for several rounds of strong storms.
High instability and potential for a decent nocturnal LLJ makes
Sunday into Monday the current best estimate for the next
chances at severe weather, but details are unclear at this time.
The jet pattern becomes less clear after Monday, and confidence
in storm chances is low beyond Monday.


&&

.AVIATION /18Z TAFS THROUGH 18Z THURSDAY/...
Issued at 1232 PM CDT Wed Jul 22 2026

VFR cumulus extend across the state currently and will likely
continue through the afternoon. Some sites are near MVFR criteria,
and though coverage will likely increase over the next two hours,
ceilings will also rise. Potential for patchy fog this overnight is
being monitored, particularly in northeast Iowa. At this time,
probability of any impacts to the terminals is <30%.

&&

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

&&

$$

SHORT TERM...De Bruin
LONG TERM...De Bruin
AVIATION...De Bruin