185
FXUS63 KDMX 131109
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
609 AM CDT Mon Oct 13 2025

 ...Updated for the 12z Aviation Discussion...

.KEY MESSAGES...

- Dry and pleasant today with highs in the mid-60s northwest to
  mid-70s southeast, less humidity, and modest northwest
  breezes.

- Rain chances return from the west overnight tonight and become
  more widespread and higher (30-60%) on Tuesday and Tuesday
  night. A few thunderstorms may occur Tuesday night, but no
  severe weather is anticipated.

- Warmer again by Thursday and Friday, with highs in the 70s to
  lower 80s and rain chances at times.

&&

.UPDATE...
Issued at 203 AM CDT Mon Oct 13 2025

Removed POPs from the daytime forecast for today, with POPs then
gradually increasing from the west tonight and into Tuesday.
Negligible instability and limited forcing for ascent support
only light showers, and no hazardous weather or impacts are
expected. Also increased minimum temperatures for
tonight/Tuesday morning a bit, as it appears cloud cover will
mitigate cooling overnight especially in our southern counties.

&&

.DISCUSSION...
Issued at 238 PM CDT Sun Oct 12 2025

A look at the large-scale weather pattern this afternoon shows a
deepening surface low pressure system centered over North Dakota,
which is in relation to a large trough that covers the entire
western CONUS today, while another trough sits over the southeast
CONUS while high pressure in the northeast extends into the Ohio
Valley. This is resulting in dry air to remain at least in the
eastern half if not more of Iowa this afternoon. With weak
forcing into western/northern Iowa, returns from radar indicate
showers over the same area trying to track eastward, but have
been fighting this dry air, with most sites reporting no precip
outside of trace amounts at Estherville and Fort Dodge. Winds
also remain breezy from a tightened pressure gradient that has
developed across the Midwest in relation to the deepening
surface low, with southeasterly winds sustained around 10-15 mph
and gusts reaching 25-30+ mph, strongest over northwest Iowa
where at least a few gusts near 40mph were reported. As moisture
return increases late this afternoon to evening with the
surface low pivoting further north/northeast and a cold front
entering the state that will bring better forcing into the
state, additional shower activity is expected to occur as the
column should fully saturate through the evening. These showers
are expected to become scattered across the state this evening
and gradually move east/northeast tonight into Monday morning,
ending before sunrise. Very little instability, if any overhead
should keep any storm potential quite low, with at most a
rumble of thunder or two possible. As the front passes through
into Monday morning, winds will gradually shift northerly behind
the front, which will lead to slightly cooler highs to start
the work week as values reach into the 60s to mid 70s.

Surface high pressure over Canada will drop into the Upper Midwest
Monday and remain over the region into midweek, as upper-level
ridging takes over and 850mb flow shifts southeasterly Tuesday
before shifting southwesterly through Wednesday. Temps will be
cooler Tuesday in the upper 50s northwest to upper 60s southeast,
then warming up in the 60s to low 70s Wednesday. With the surface
high pressure influence remaining mainly north of Iowa, model
guidance indicates low-level convergence with the frontal
boundary within the larger scale flow lifting northeast out of
southern part of the Central Plains and back into Iowa, along
with lingering mid-level moisture return out of the Pacific,
indicating additional chances for at least some showers into
southwestern Iowa Monday evening and becoming more scattered
across Iowa Tuesday. Very little instability overhead per
guidance will keep thunderstorms out of the forecast for the
early work week. By Wednesday, the aforementioned surface high
pressure drops southeast, scraping eastern Iowa, while the upper
level ridge elongates vertically over the Midwest while further
over the western CONUS, a large deepening trough continues to
circulate. Increasing southwesterly flow will take over the
region, with warm and breezy conditions expected towards the end
of the work week. Temperatures are expected to increase through
the 70s to low 80s. Additional low chances for occasional on
and off shower activity remain possible until Thursday, then
the western trough finally advances eastward, with lee
cyclogenesis developing a surface low that gradually lifts
northeast into the Midwest. Scattered showers and even some weak
thunderstorms activity is possible (20-30%) with the initial
warm air advection wing, followed by a cold frontal passage by
Friday where higher PoPs are indicated (30-50%) in the current
forecast. As expected, differences among models exist this far
out, so further details such as exact coverage and timing are
not well known and will largely depend on how the pattern
evolves over the next several days, so will be monitoring
closely and making changes as more data becomes available.

&&

.AVIATION /12Z TAFS THROUGH 12Z TUESDAY/...
Issued at 609 AM CDT Mon Oct 13 2025

VFR conditions will prevail through the 12Z TAF period. A brief
MVFR ceiling may be possible in the next hour or two, mainly at
ALO, but otherwise skies will clear out. Toward the end of the
period, near 12Z Tuesday and beyond, low clouds and -RA could
move back into the area from the south. This potential will be
assessed in subsequent TAF issuances.

&&

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

&&

$$

UPDATE...Lee
DISCUSSION...Bury
AVIATION...Lee