008
FXUS63 KDMX 142346
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
646 PM CDT Tue May 14 2024

 ...Updated for the 00z Aviation Discussion...

.KEY MESSAGES...

- Scattered showers in southeast to central Iowa this afternoon
  taper off this evening.

- Warming trend into the end of the week/weekend with additional
  thunderstorms chances Wednesday evening into Thursday and
  again this weekend. Severe chances remain low at this time.

&&

.DISCUSSION...
Issued at 226 PM CDT Tue May 14 2024

Scattered showers have persisted across southeast Iowa throughout
the day as the surface low continues to slowly swirl to our south.
Another more isolated, and short-lived, shower has developed towards
Boone county with associate more agitated cumulus showing up in GOES
imagery. This has mainly been diurnally driven with just enough
available moisture for isolated shower development. All of
these showers should taper off this evening as the system
finally shifts east.

Wednesday will see a quieter day to start as the next system swings
across the northern Plains towards Iowa. With light winds and
lingering moisture, a few high resolution models have indicated
chances for patchy fog development in southern Iowa on Wednesday
morning though lingering cloud cover may squash this potential. By
evening showers and a few thunderstorms will approach the area
with a front associated with a trough across the central US.
Forcing is weak and focused in the northern and southern
streams that split Iowa on either side. Modest MLCAPE less than
500 J/kg and 0-6km shear at or under 30 kts will limit much in
the way of severe potential. The boundary continues across Iowa
on Thursday with some diurnal restrengthening Thursday afternoon
towards eastern iowa. Even so, the parameter space remains
similar to Wednesday with very skinny CAPE profiles and a very
low severe threat.

The unsettled pattern continues this weekend and into next week
(along with a warming trend), however model solutions diverge with
less confidence in precipitation windows and placement.
Broadly, additional chances exist with a shortwave Saturday into
Sunday. GFS favors a cutoff low bringing precipitation to
southern Iowa Friday night into Saturday, slowing the shortwave
into Sunday. Meanwhile the Euro is more progressive and without
the cutoff low, pushing the shortwave through on Saturday with
less QPF. For now have opted for a middle ground scenario but
will need to fine tune as more data is available. Both also
indicate another more robust system early next week, though
significant differences in timing and placement exist.

&&

.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 646 PM CDT Tue May 14 2024

Confidence is medium or more than VFR conditions will persist
across northern Iowa through the period, including
KFOD/KMCW/KALO, with generally diurnal cumulus cycles. However
MVFR stratus should affect KOTM for at least the next several
hours, with at least MVFR conditions due to stratus, and
potentially visibilities, affecting other portions of southern
Iowa later tonight and into the early morning hours Wednesday,
including KDSM and KOTM, with confidence no better than medium.
IFR fog is expected across SW Iowa, removed from those sites,
however that potential cannot be ruled out in other locations
over southern Iowa farther east as well.

&&

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

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Small