258
FXUS63 KDMX 160634
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
134 AM CDT Thu Jul 16 2026

.KEY MESSAGES...

- Hot and humid conditions continue through the weekend, with
  heat indices nearing 100 degrees each day.

- Low (~20%) thunderstorm chances return this afternoon and
  evening, and again on Friday. The threat of severe weather
  remains low.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 134 AM CDT Thu Jul 16 2026

A deep-layer ridge continues to dominate Iowa weather, but will
begin to reorient itself just a bit over the next couple days.
At 500 MB, the ridge currently stretches from the Midwestern
U.S. east southeastward to the mid-Atlantic coast around
Virginia and North Carolina. A slight weakness with minimally
enhanced vorticity is creeping across portions of Arkansas and
Missouri at the current time, and will pinch off the ridge and
drift toward southern Iowa by tonight, then eastward into
Illinois on Friday. Concurrently, the surface ridge that has
blanketed Iowa for the last few days will slowly begin to
retreat eastward. The sensible effects of this general scenario
will be twofold. First, the nearly calm winds we have seen for
days will finally pick up just a bit from the south southwest
by tonight and Friday, but still remain light at less than 10
MPH. Second and more notably, the area of weak vorticity and
deeper moisture over Missouri will bring a return of low (20%)
thunderstorm chances at times from this afternoon into Friday.
Given the very weak ambient flow, this will be typical mid-
summer "popcorn" storms that will pulse up and down quickly and
carry a minimal severe weather threat. Have maintained isolated
thunderstorms in the forecast across much of the area this
afternoon and evening, and again on Friday.

Aside from the return of isolated thunderstorms and a light
breeze, heat and humidity will continue through the end of the
week. Dewpoints will increase slightly today as the moisture
moves in from Missouri, however, scattered clouds may also
suppress temperatures just slightly. The net effect will be
little chance in Heat Index values, which will still peak
generally in the upper 90s each day. The good news is that the
smoke from Canadian wildfires, which is having significant
impacts in parts of the Great Lakes region, is still expected
to remain northeast of our area, to the north of the 500 MB
ridge.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 217 PM CDT Wed Jul 15 2026

Over the weekend, the ridge which has been over the region will
continue to break down as the high weakens, putting us on the
periphery of it through the weekend and into early next week. The
most notable feature currently in the long term forecast is the
potential for a shortwave to affect the region Sunday night into
Monday which could lead to shower and thunderstorm potential
returning to the area. At the same time, LREF ensemble clustering
shows the ridge may continue to hold out which would lead to a
higher potential farther to the east. At this point, it`s too far
out to try and pinpoint a location. Otherwise, warm and humid
conditions continue before the ridge breaks down further, bringing
some amount of relief from the heat during the early part of the
workweek.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1045 PM CDT Wed Jul 15 2026

VFR conditions continue late this evening/early this morning,
although pockets of patchy fog/mist have started to develop over
the area. This fog is not expected to be widespread, but could
very well impact all sites. Any fog that develops will dissipate
after sunrise. Otherwise, winds will be light with partly
cloudy skies today. Scattered showers and thunderstorms are
possible in the afternoon, mainly over the north and east.
However, coverage will be sparse and therefore confidence is too
low to include in TAFs at this time.

&&

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

&&

$$

SHORT TERM...Lee
LONG TERM...67
AVIATION...Dodson