866
FXUS63 KDMX 300732
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
232 AM CDT Thu Apr 30 2026

.KEY MESSAGES...

- Intermittent shower chances through Friday. Isolated non-
  severe thunderstorms may occur.

- Frost/Freeze potential limited tonight due to cloud cover
  potential. Greater chance for Frost/Freeze Friday night into
  Saturday morning.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 228 AM CDT Thu Apr 30 2026

Upper level low pressure is settling into the central Great Lakes
region and will remain in that vicinity through Friday. Two distinct
PV anomalies/short wave clusters will drop through the resultant
northerly flow. The first will arrive today while the second system
arriving late tonight into Friday. This will result in chances for
showers and perhaps a few non-severe thunderstorms. The thunderstorm
chances will be mainly across southern Iowa on Friday as static
stability becomes low with low theta-e difference between the
tropopause and the boundary layer along with some modest CAPE
developing from surface instability. The other potential impact of
the second system is increasing clouds tonight from north to south
and the impact on frost/freeze potential. Will be holding off on any
frost/freeze headlines because expected there will be a broad area
of cloud cover and will limit low temperature potential tonight and
the clouds will impact frost formation. There will still be pockets
of frost where holes in the cloud cover occurs but pinpointing those
areas while that system is still over northern Alberta is difficult.
Friday night and Saturday morning will have a greater potential for
frost/freeze with subsidence behind the departing system and surface
high pressure arriving. There is a scenario where low temperatures
reach the mid to upper 20s over northern Iowa as dew points in the
20s advect in and the potential for radiational cooling is
increasing.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 228 AM CDT Thu Apr 30 2026

Saturday will remain cool but pleasant with light winds followed by
warm advection Saturday night into Sunday as the northerly upper
level flow relaxes and becomes more northwesterly. Upper level low
pressure develops near Hudson Bay late Sunday and will result in
long wave troughing through the Upper Midwest by mid next week. This
will bring a cold front through the state Monday night and Tuesday.
This will bring the next chance for precipitation along with another
round of cooler weather. Upper level ridging will occur over the
western CONUS during this time. That ridging will move east late
next week and will bring a return to warmer weather.

&&

.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1102 PM CDT Wed Apr 29 2026

Refinements made to timing of showers. Trends have favored VFR
over MVFR now, so raised cigs. Monitoring for more precipitation
potential after 00z in northern terminals.

Wind shift timing has also been adjusted with gusts to around
20kts common behind it.

&&

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

&&

$$

SHORT TERM...Donavon
LONG TERM...Donavon
AVIATION...Jimenez