Area Forecast Discussion
Issued by NWS Des Moines, IA

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937
FXUS63 KDMX 022314
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
614 PM CDT Thu Oct 2 2025

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

.KEY MESSAGES...

- Elevated fire weather concerns this weekend, especially for
  field fires with warm and breezy to windy conditions both
  days. Any spark could cause a fire in a field, which could
  spread quickly!

- Increasing chances for showers and storms from late Sunday
  into at least early next week.

- Conditions more seasonal next week.

&&

.DISCUSSION...
Issued at 220 PM CDT Thu Oct 2 2025

The remnant shortwave energy is passing over and away from Iowa
early this afternoon with mid-level ridging returning to the
region. This will keep our pattern very warm and dry through
Saturday if not Sunday. Each day during this period may see
diurnally driven fair weather cumulus clouds, but should
otherwise be quite sunny with highs well into the 80s to around
90 degrees. To the west of the ridge, an amplified longwave
trough is arriving over the Western CONUS today into Friday.
This trough will aid in the development of surface low pressure
over the Rockies that deepens through the weekend as it moves
into the eastern Dakotas. With the pressure gradient tightening
between this low and sprawling surface high pressure over the
Eastern US during this period, an increase in winds is expected.
This won`t be too noteworthy on Friday as winds at the top of
the mixed layer will be 20 knots or less, but as the low deepens
and the gradient tightens with southwesterly flow
strengthening, wind gusts over 40 mph will be possible over
northwest into perhaps north central Iowa. With the warm and
windy conditions, the concern will be on fire weather,
particularly field fires with the cropland fire danger in the
very high to extreme category. Cropland is cured and with farm
equipment working to harvest crops, the conditions will be ripe
for fire growth if a spark starts a fire. This could make fire
departments rather busy this weekend.

As we move into Sunday, the longwave trough over the western US
will near Iowa with a shortwave trough pivoting through and out
its base. This will help to bring a surface cold front through
the state Sunday into Sunday night. With this front and to some
degree an increase in cloud cover, the high temperatures will be
a few to several degrees lower in the low and middle 80s on
Sunday. Moisture will pool along the front and with the phasing
of stronger thermodynamic and nearby kinematic forcing, will
aid in scattered showers and thunderstorms developing by later
Sunday if not by Sunday night. While this boundary will sink
into Missouri early next week, lingering forcing and isentropic
lift over the boundary will keep rain chances in the forecast
through at least Tuesday. During this period, instability is
generally meager to at best modest with higher deep layer shear
so any severe weather signal is not readily apparent here or in
the AI/ML space beyond 5%. While warm cloud depths will be
seasonally high and precipitable water values may reach 1.5
inches at times, our dry stretch of weather should allow soils
to readily soak up any of the anticipated rainfall.
Deterministic models show a 1 to 2 inch streak across some
corridor of the state, though the current National Blend of
Models shows just a 20 to 30% chance of exceeding one inch over
the three day period ending Wednesday morning. Temperatures will
return to seasonal levels next week as well in the wake of the
front.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 612 PM CDT Thu Oct 2 2025

VFR conditions continue through the period. Winds will continue
to diminish this evening, with light southerly winds around 5
kts expected overnight. Skies remain mostly clear through
tomorrow, with winds increasing to around 8 to 10 kts through
the day Friday. Some gusts around 15 to 20 kts are possible
tomorrow afternoon, generally over western and northwestern
Iowa.

&&

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

&&

$$

DISCUSSION...Ansorge
AVIATION...Dodson