323
FXUS63 KDMX 231940
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
240 PM CDT Thu Jul 23 2026

.KEY MESSAGES...

- Cooler temperatures will be in place through Friday, then
  increase through the 90s this weekend into early next week.

- Showers are expected to increase in coverage overnight tonight
  into Friday, with pockets of heavy rain possible in southwest
  Iowa.

- Additional showers and storms are possible later this weekend
  into early next week, with some potential for severe weather.
  Timing and location will be better determined in the coming
  days.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 240 PM CDT Thu Jul 23 2026

Surface analysis this afternoon shows a large area of high pressure
centered over the Ohio Valley, extending westward across Iowa. Light
south/southeast winds are noted over the state, with much of the
area seeing diurnally driven cumulus development given the presence
of moisture aloft, as temperatures increase into the mid to upper
70s. Satellite imagery is also detecting a thin area of smoke over
the Northern Plains that extends over into parts of far northern
Iowa, though this shouldn`t extend further south and will also
remain aloft. More notable mid-level moisture content is noted
over South Dakota through western Missouri, as seen from a
thicker blanket of clouds in these areas, which will gradually
shift eastward this evening into Friday. Increasing mid-level
vorticity advection and low-level theta-e advection into Iowa,
especially over far southern Iowa into northern Missouri in
conjunction with a passing shortwave riding the western CONUS
thermal ridge will allow for increasing chances for rain later
tonight. One of the challenges that remain is the exact timing
of full saturation of the column, given the notable low level
dry column of air that remains overhead as the surface high
pressure will continue to influence much of the state. While the
shortwave arrives over western Nebraska late this afternoon to
evening, will likely see some light returns on radar over
western Iowa indicating rain falling through the dry low levels,
before better saturation occurs generally after midnight over
west/southwest Iowa from a push of low-level moisture and
forcing as the low level jet increases over far western Iowa
late tonight into early Friday. Latest guidance continues to
trend lower on overall rainfall amounts as the axis of heaviest
rainfall shifts a bit further south out of Iowa, now generally
over eastern Nebraska into northern Missouri where better
forcing and moisture availability is indicated. However, the
potential for heavy rain still exists mainly Friday morning,
given PWATS around 1.75-2 inches and warm cloud depths around 15
kft. While dry antecedent conditions and mature crops should
largely mitigate concerns for flooding, a low potential for very
localized flash flooding cannot be ruled out in an urban area
in southwest Iowa. Minimal instability and weak shear will keep
the storm potential very low, though some occasional thunder
cannot be ruled out at times. Rain showers are generally
expected to remain over central to southern Iowa throughout the
morning before tapering off, though portions of far southern
Iowa could still see some lingering showers throughout the
majority of the day. Total rainfall amounts are generally
expected to remain under an inch, with localized areas of 1-2
inches possible in southwest Iowa where any heavy rain potential
lies.

Thick cloud cover overhead throughout the day, along with the rain
and light southeast flow will result in slightly cooler temperatures
than in previous days, with below normal values in the mid 70s for
most areas, and some isolated upper 70 values in northern Iowa where
less cloud cover is anticipated. Certainly a perfect day to spend
time outdoors once the rain ends!

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 240 PM CDT Thu Jul 23 2026

As the thermal ridge nudges further eastward into the weekend and
early next work week, a stronger push of low-level southwesterly
flow will bring warmer and more humid air into the Central Plains.
This pattern shift will allow for temperatures to rise significantly
with values through the 90s, especially Sunday and Monday. Dewpoint
values topping out through the 70s, paired with these temperatures,
will lead to heat index values near 100-105+ degrees over western
Iowa Saturday, and much of the area Sunday and Monday. The upper
level northwesterly flow into Iowa though in relation to the closer
proximity of the thermal ridge will also introduce additional
chances for showers and thunderstorms, particularly into Sunday
morning and again late Sunday into Monday. Smoke also could limit
highs a bit Saturday as guidance suggests a return through the day.
All important things to watch over the coming days, but at least in
terms in heat headlines, the potential is certainly there for some
areas of Central Iowa. The warm and moist airmass Sunday through
early next week will bring about to a substantial increase in
instability and favorable shear profiles to reintroduce severe
weather potential as various shortwaves round this ridge into
the Midwest. At this time, guidance suggests, as mentioned
earlier in this paragraph, early Sunday morning and especially
late Sunday into Monday morning with the increasing LLJ into
Iowa to be possible targets for some potential severe weather,
with the SPC highlighting north/northeast Iowa in a 15% risk.
Will keep a close eye on this over the coming days as details
become more clear. The thermal ridge by midweek next week moves
very little, with Iowa still in the ring of fire as additional
waves are indicated in long term guidance to pass through,
keeping the pattern more on the active side.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1237 PM CDT Thu Jul 23 2026

Areas of diurnal cumulus are expected to increase in coverage
through this afternoon before fading after 00-01z, with ceilings
near MVFR at times. Otherwise, will see a gradual increase in
mid to upper level clouds this evening and especially through
Friday morning as a system approaches the region. Rain showers
are expected to increase across the state mainly after 06z, with
impacts mainly expected to occur at KFOD, KDSM and KOTM.
Adjustments on exact timing are expected to continue over the
next few issuances in accordance with latest model trends. Winds
will generally remain light out of the southeast today, then
increase with slightly breezy winds near the end of the current
period.

&&

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

&&

$$

SHORT TERM...Bury
LONG TERM...Bury
AVIATION...Bury