965
FXUS63 KDMX 021707
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1207 PM CDT Tue Jun 2 2026

 ...Updated for the 18z Aviation Discussion...

.KEY MESSAGES...

- Drier conditions today through the day Wednesday. Highs around
  80 degrees or in the low 80s with breezy winds over western
  Iowa.

- Pattern turns more active starting Wednesday night and
  Thursday with multiple rounds of rain and thunderstorms
  possible into this weekend.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 155 AM CDT Tue Jun 2 2026

Early morning GOES-East upper level water vapor imagery shows
an active scene over the central Plains and down into the Deep
South with ongoing convection. Of most interest to our forecast
are the storms over Nebraska, which have shown a trend downward
per cloud top temperatures and lightning activity. SPC
mesoanalysis shows weaker MUCAPE and effective shear as these
storms move towards the Iowa border this morning. Thus, it is
not surprising that convective allowing models (CAMs) and global
models are in good agreement that these storms will fizzle out
before reaching our forecast area if not the state. While the
environment is not conducive to maintaining severe storms as
outlined above, a sprawling zone of surface high pressure is
sinking into and over the Great Lakes today, which is directing
drier air into the state. A few models such as the GFS,
Canadian, and RRFS (MPAS core) try to paint light QPF over our
far western forecast area from the remnants of the Nebraska
storms or some sort of outflow generated activity. This is in
line with the eastern extent of the latest day 1 SPC general
thunder outlook; however, given the amount of dry air shown in
soundings and subsidence from the high along with the rest of
guidance pointing to dry conditions, am planning to carry a dry
forecast today. Otherwise, today will be seasonably warm with
highs a few degrees either side of 80 degrees, dewpoints falling
back into the 50s western and central to 40s eastern Iowa, and
breezy winds with ample sunshine.

The upper level omega blocking pattern will be starting to break
down on Wednesday while the surface high pressure shifts from the
Ohio Valley into the Middle Atlantic States. This will offer another
day of dry conditions for central Iowa with highs just a bit higher
in the low 80s with a bit more cloud cover than today/Tuesday
with breezy winds once again over western Iowa. As the high
pressure does move away from the region, the plume of higher
precipitable water values that will be west of Iowa will begin
to drift closer, which is discussed in more detail below.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 250 PM CDT Mon Jun 1 2026

Wednesday night and through the second half of the week will see a
slight change in the pattern, as the eastern US long-wave trough
departs eastward and the surface high follows along with it. Return
flow on the backside of the departing high will advect warm moist
air up into the state, meeting with another shortwave trough along
the US/Canada border Wednesday night into Thursday. This will bring
the return of shower and thunderstorm chances to Iowa, mainly over
northwest into northern Iowa, although rain could develop throughout
the area as theta-e advection increases ahead of the wave. This
Wednesday night into Thursday rain will kick off a more active
pattern through the end of the week, as we transition to more of a
zonal flow pattern with multiple shortwave passages into the
weekend. Instability will also be increasing through the end of the
week, as the warmer and higher dewpoint air works up into the state.
It`s a bit too early to dig too far into the severe weather
potential, but Friday looks like it has the greatest potential for a
few strong storms, albeit limited by low wind shear values. Machine
learning probabilities are keying on Friday as well, putting a 5 to
15% probability for severe storms (equivalent to a marginal risk
from SPC) on Friday. Of similar concern will be the potential for
multiple days of rainfall Wednesday night through Saturday, some of
which could be rather efficient as the better moisture stream and
PWATs pivot westward into Iowa. This could be some much needed
rainfall, provided it doesn`t all fall in one spot. Potential severe
weather and hydro concerns will continue to be evaluated in the
coming days. Warm, summer-like conditions persist through the
weekend and into early next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1204 PM CDT Tue Jun 2 2026

VFR conditions prevail through the TAF period. Winds will be
light to occasionally breezy out of the east southeast at 10 to
15 kts, gusting to around 18 to 20 kts at times. Winds and gusts
diminish overnight, then pick up out of the south again on
Wednesday.

&&

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

&&

$$

SHORT TERM...Ansorge
LONG TERM...Dodson
AVIATION...Dodson