644
FXUS63 KDMX 041928
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
228 PM CDT Sat Oct 4 2025

.KEY MESSAGES...

- Warm, dry, and windy conditions through Sunday, making for
  elevated fire weather concerns. Cropland is most susceptible
  and extreme caution should be used.

- Spotty showers are possible from late Sunday afternoon in
  northwest Iowa, moving across the area and becoming more
  widespread on Monday.

- Cooler highs in the 60s and 70s this week.

&&

.DISCUSSION...
Issued at 228 PM CDT Sat Oct 4 2025

Warm, dry, and windy this afternoon around Iowa. By 2pm temperatures
had warmed into the mid to upper 80s while dewpoints were near 60 -
making for relative humidity in the 35-45% range so far. A quick
look at the surface maps shows a tight pressure gradient
setting up across Iowa with high pressure to the east and low
pressure to the west. This gradient, coupled with the dry air
and deep mixing in place, has resulted in gusts of 25-35+ mph so
far this afternoon with a few isolated gusts of 40+ mph. While
grasses remain fairly green, cropland is cured and susceptible
to fire weather concerns. Extreme care should be used with fires
or sparks today.

This evening the loss of diurnal heating will help to diminish
surface winds as an inversion sets up. By Sunday those breezy
conditions and warm temperatures will be back again, however. The
low will creep closer with a boundary reaching western Iowa on
Wednesday, bringing additional moisture and scattered cloud cover to
the area. This will battle the dry air in place and fire weather
concerns remain elevated ahead of the boundary passage on Sunday. A
spotty sprinkle or light shower is possible on Sunday, but dry air
will prevent anything more substantial.

By Monday deeper moisture arrives into the area as the western US
trough elongates and pushes east across the plain and midwest.
Sounding show continued moistening of the column by Sunday
night and Monday, allowing for more efficient rain production.
Model consensus is around 1-1.5 inches of rain with the line of
showers. With very little instability (<200 J/kg) and shear
lagging behind the boundary, the potential for stronger storms
is very low. Model struggle with evolution into Tuesday and
beyond. While the Euro favors a quicker exit as the front clears
the area by Tuesday morning, the GFS is slower with the
boundary and associated shower lingering through Tuesday night.
These timing differences also influence timing for a mid week
shortwave, something both models develop but with a difference
of ~36 hrs. Aside from precipitation uncertainty, temperatures
are expected to come down to more seasonal values with highs in
the 60s to 70s this week and lows in the 40s to 50s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SUNDAY/...
Issued at 1227 PM CDT Sat Oct 4 2025

Winds across Iowa are gusting 25-35 kts this afternoon with
highest gusts in northwest Iowa. This evening winds will ease
at the surface as daytime heating is lost and the inversion sets
up. This will result in LLWS across all sites. By Sunday
morning daytime mixing returns, washing out the inversion and
bringing back gusts of 25-35 kts.

&&

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

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Hagenhoff