757
FXUS63 KDMX 081715
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1215 PM CDT Wed Oct 8 2025

 ...Updated for the 18z Aviation Discussion...

.KEY MESSAGES...

- Cool this morning with a chance for some patchy frost in
  northern Iowa, with another chance over northeast Iowa into
  Thursday morning. Highs in the 60s to 70s.

- Winds pick up Thursday, with highest gusts over northwestern
  Iowa. Elevated fire weather conditions are expected northwest
  with these winds, lower RH values and dry crops.

- A slight chance (20-30%) for rain showers mainly central to
  eastern Iowa late Thursday into Friday. A few weak storms are
  also possible.

&&

.UPDATE...
Issued at 340 AM CDT Wed Oct 8 2025

Dry and chilly conditions across the region this morning, with
values over Iowa in the 40s over central to southern Iowa, and even
cooler temperatures in the upper 30s over northern Iowa, as a large
area of surface high pressure centers itself over Minnesota and
covers much of the Midwest. Given clear skies and light winds with
the nearing freezing conditions in northern Iowa, patchy frost could
develop for a short time before sunrise, while areas further south
remain warmer in the 40s. The influence of high pressure overhead
but gradually departing eastward through much of Thursday will keep
continued dry weather over Iowa, with seasonal highs today in the
60s under mostly sunny skies. Another night of cooler
temperatures in the upper 30s north, with mainly clear skies
and light winds could again lead to some isolated patchy frost
over parts of northeastern Iowa into Thursday morning. Sensitive
plants should be covered or brought indoors as needed in the
affected areas. With departing high pressure Thursday, low-level
winds return out of the south, which will advect warmer air
into the state through the end of the work week and even the
weekend, with highs in the 70s each day. Winds will be breezy
Thursday with increasing southerly flow, with gusts reaching
25-30+ mph, highest across northwestern Iowa. These breezy
conditions, with RH values dropping into the upper 30s will
result in high to very high fire danger for cropland over much
of northwestern Iowa. Extra care will be needed in preventing
sparks that could lead to fire starts and quick spread.

A positively tilted shortwave trough is forecast per model guidance
to track southeast across the Great Lakes late Thursday into Friday
morning, with weak moisture and forcing into Iowa that will lead to
low chances (20-30%) for showers, gradually departing Friday
morning. Models vary on the coverage of this activity, with CAMS
depicting scattered showers over central to western Iowa as the
boundary in relation to the upper level feature passes through,
while the Euro/GFS has more widespread coverage into Iowa. At this
time, the CAM solutions seem more reasonable but will be keeping an
eye on this as more data becomes available. Cannot rule out a few
weak elevated storms with any showers given MUCAPE values less than
500 J/kg and favorable shear per soundings. Dry conditions are
expected after sunrise across the state Friday and remain into the
start of the weekend.

&&

.DISCUSSION...
Issued at 1255 PM CDT Tue Oct 7 2025

Today and Tomorrow... High surface pressure and northwest flow
aloft will advect additional cool air in overnight. With the
high pressure little pressure gradient and therefore light
winds and clear skies. All of this will create a good setup for
radiational cooling tonight. This could result in some frost in
parts of northern Iowa where the coolest temperatures are
expected. The general pattern will hold into tomorrow with a
very similar day expected. Tomorrow night though, the focus of
the coolest air should shift east to eastern Iowa.

Thursday into the Weekend... A change in the pattern arrives on
Thursday with a shortwave moving through. This will provide
enough synoptic forcing and a chance of some rain showers.
Model forecast profiles do not look favorable for instability
and this matches the SPC day 3 outlook with no general thunder
over Iowa. Warmer air moves back in Friday into the weekend with
highs back in the lower 80s once again possible. The low all
these air masses is associated with will also have frontal
passages associated with it. Along these fronts will be our next
chances for rain and gusty winds. Still a fair amount of spread
within global ensemble guidance (as expected). So will be
keeping an eye for future updates on where this trends to hone
in on forecast rainfall timing and amounts.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 1215 PM CDT Wed Oct 8 2025

VFR will continue through the period with clear to mostly clear
skies today (just some afternoon cumulus clouds possible). Some
high cloud cover will build in tomorrow, but will remain VFR.
Winds will remain under 10 knots through tonight. Winds will
pick up again tomorrow with gusts in the 15 to 20 knots range in
the late morning to afternoon.

&&

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

&&

$$

UPDATE...Bury
DISCUSSION...NC
AVIATION...NC