125
FXUS63 KDMX 280720
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
220 AM CDT Tue May 28 2024

.KEY MESSAGES...

- Scattered showers and perhaps a few thunderstorms today with
  very low severe risk.

- Quiet through the middle of the week with showers and
  thunderstorms returning to the forecast Thursday into Friday
  and the upcoming weekend.

&&

.DISCUSSION...
Issued at 220 AM CDT Tue May 28 2024

Quiet across the area early this morning as Iowa sits between two
shortwaves embedded within the parent trough a cross the upper
midwest. This shows up nicely in GOES water vapor imagery as
one shortwave drops out of the Dakotas (more on the next) and
the other moving across southern Wisconsin. By later this
morning that shortwave across the Dakotas will drop across Iowa,
providing enough forcing for scattered showers across the area.
Instability is weak, under 500 J/kg, so the severe threat is
pretty low, but a few rumbles of thunder are possible. Soundings
also remain pretty dry across the area which will limit more
widespread shower development and reduce QPF. Expect under 0.1"
with most showers into the afternoon. With drier low levels,
gusty winds may develop with showers this afternoon due to
evaporative cooling but that should be the extent of any
impacts.

This will be followed by a dry period Wednesday into the first part
of Thursday as a narrow ridge passes across the area, squeezed
between entering and exiting troughs. By Thursday afternoon an upper
level trough moves towards the area with southerly flow pulling deep
moisture transport back into the area. The system stalls out
Thursday into Friday across western Iowa before pushing across
the area Friday. The instability axis looks to remain south of
the area based on current guidance, which would help to limit
severe potential across the area with this system. Still plenty
of time for this to shift in the coming days. Another wave looks
to follow quickly behind, however model solutions diverge at
this time frame with substantial differences between the most
recent GFS and Euro runs.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1146 PM CDT Mon May 27 2024

Much of the period will feature VFR conditions, though latest
guidance suggests a period of sub-VFR conditions at ALO around
12z. Not a lot of confidence given the recent change and
ensemble support is less than 50% so have omitted for now. Have
introduced VCSH at MCW in the morning as there is general
agreement in showers moving southeast into north central Iowa in
the morning. This may need to be expanded to ALO and FOD in
future updates. Otherwise, SCT to BKN VFR ceilings will prevail
during the day Tuesday.

&&

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

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Ansorge