350
FXUS63 KDMX 211911
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
211 PM CDT Tue Jul 21 2026

.KEY MESSAGES...

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

- Meaningful chances for rain return Thursday night into Friday
  morning in southern Iowa where rainfall totals over half an
  inch are possible.

&&

.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 210 PM CDT Tue Jul 21 2026

Relief from the heat finally sets in today as cold air advection in
the wake of yesterdays cold front brings in temperatures in the 70s
and 80s. Diurnal heating has caused a wide area of cumulus to form
across northern to central Iowa, but aside from that skies are
overall clear and conditions dry. Some smoke is still hanging
around, mainly aloft, but not seeing any visibility reductions
across the state so did not include it in todays forecast. Efficient
mixing down of stronger mid level wind is already well underway, and
wind gusts of 20-30 mph will likely continue through the end of the
afternoon today.

By Wednesday, high pressure becomes well established across Iowa.
However, a subtle shortwave is expected to move through the enhanced
mid level flow on the periphery of the 500mb ridge sitting on the
southern and central plains. As this shortwave approaches in the
afternoon, the 500-700mb layer will become saturated and form a few
showers over southwest Iowa. That said, this rain will have to fall
through the the dry Canadian airmass that is being advected in
today, and most of it will likely evaporate before reaching the
surface. Still, included isolated to scattered PoPs but minimal QPF
for southwest Iowa through the afternoon. Highs will also be even
lower on Wednesday due in part to the continued cold air advection
through the morning and increased cloud cover during the daytime
heating.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 210 PM CDT Tue Jul 21 2026

A stronger wave looks to move across the top of the ridge by
Thursday evening and bring us our next chance for meaningful precip.
Instability will be quite limited so severe weather is unlikely,
though some thunder is possible Thursday night into Friday morning
in southern Iowa. The nocturnal LLJ returns to our vicinity during
the Thursday overnight, with the nose centered over southwest Iowa.
This should erode the dry air and allow the quite saturated mid
levels to rain down to the surface. The main story will be QPF
amounts. WPC has southwest Iowa in a marginal ERO for Thursday and
Friday, and PWATs are well over 2 inches. There is a large QPF
spread across the models, but a few give spots in southern Iowa 1-2
inches of rain. By the weekend, the ridge intensifies over the
Dakotas, bringing us another period of heat. We may breach the 90s
again on Saturday, and Sunday/Monday look to be the warmest as a
more substantial EML is advected in.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1229 PM CDT Tue Jul 21 2026

VFR cumulus are currently spread across most of the state. They have
been bordering on MVFR for the past several hours but ceilings are
expected to continue rising through the afternoon. Winds will also
stay gusty this afternoon, with gusts from the NW up to 25-30 knots
at most sites. Both the clouds and gusts will dissipate around
sunset later today.

&&

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

&&

$$

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