370
FXUS63 KDMX 212002
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
202 PM CST Fri Nov 21 2025

.KEY MESSAGES...

- Light rain south this afternoon, ending tonight.

- Mild, dry, and mostly sunny this weekend with highs around 55 to
60 degrees Saturday and Sunday.

- Rainy and dreary Monday into Monday night, then much cooler by
  the latter half of next week.

&&

.DISCUSSION...
Issued at 202 PM CST Fri Nov 21 2025

A deep but weakening low pressure system is moving from Kansas into
Missouri this afternoon, with a broad deformation zone wrapped
around its northern hemisphere roughly from northeastern Kansas
up along the Iowa/Missouri border. This is spreading thick high
clouds and light rain across that area, however, a large
surface high pressure center is also parked across
Iowa/Minnesota/Wisconsin and is filtering in low-level dry air
from the north that is undercutting the precipitation. The
result is that while radar echoes are relatively widespread
across southern Iowa, very little is reaching the surface with
sprinkles being reported in a few areas and only a couple
stations clicking off very light measurable amounts. Meanwhile,
the cloud cover and light northerly flow are keeping
temperatures relatively cool, in the low-to-mid-40s or so. As
the low pressure system moves quickly away from Missouri into
the Ohio River valley later tonight, skies will gradually clear
and light winds will allow temperatures to fall. However, even
as the earlier mentioned surface ridge slides southeastward
into eastern Iowa and Wisconsin/Illinois, another surface
trough will quickly approach from the northwest overnight and
winds will eventually become more organized from the south
southwest. The associated modest moisture advection aloft may
allow for regeneration of some clouds in our north and west
after midnight. With these variables in mind, have decreased
forecast low temperatures just a bit tonight in our
central/southeastern sections, but avoided dropping them too
much in the northwest.

Southwesterly breezes will continue into Saturday before the
next trough comes through during the afternoon. Even then, cold
air advection will be negligible and mostly clear skies and
prevailing southwest winds will send temperatures rising
notably higher during the day. Highs are still projected in the
mid to upper 50s and a few stations may reach 60 degrees.
Another surface high pressure area will build from Nebraska
into Iowa Saturday night, but will already be departing to our
southeast on Sunday afternoon allowing for another sunny, mild,
and pleasant day with highs very similar to Saturday. In other
words this weekend will be very favorable, given the season,
for many outdoor interests including those wishing to complete
yard work, holiday decorations, and other such endeavors before
winter comes. Any such interested parties are encouraged to
take advantage of the opportunity, as it may be the last period
so conducive for some time!

By Sunday evening a large 500 mb low will be emerging from the
Four Corners region over eastern Colorado, while concurrently an
energetic northern stream shortwave comes ashore over the
Pacific Northwest coast. As the southern system drifts
northeastward at the beginning of next week it will interact
with the more quickly eastward moving northern trough.
Initially, on Monday, the southern system will be reflected in
a broad surface low pressure trough advancing from the High
Plains into the Midwest and near or over Iowa. As this low
approaches, steady moisture transport and isentropic lift will
underlie the broad forcing for ascent along the leading flank
of the 500 mb trough, combining to produce thick clouds and rain
across most or all of Iowa Monday into Monday night. Rainfall
amounts will be modest and instability appears too limited for
any substantive thunder chances, so no hazardous weather is
anticipated. However, it will make for a gray, soggy late autumn
day before the system clears out late Monday night or early
Tuesday.

From Monday night onward the long-range models rapidly diverge
in their solutions for the remainder of next week, initially due
to difficulties in resolving the interaction between the
northern and southern stream systems early in the week. The GFS
is resolving this as a large closed 500 MB low over the eastern
Dakotas by Tuesday evening, while at the same time the EC and
GEM depict a more progressive open wave crossing
Minnesota/Iowa/Wisconsin. All solutions indicate some potential
for wraparound snow as this second push moves by, but the
variations between model runs affect the southward extent of
any such snow as well as its timing, with 12+ hour differences
between various solutions. However, there is a consistent
signal that if this Tuesday or Wednesday snow does pan out, it
will be more focused over Minnesota with some lower potential
in our northern counties. This system will move off to our east
by Thanksgiving morning, with northwesterly steering flow then
persisting through Friday. There are indications that a compact
but energetic shortwave may move through the flow late next
week, however there is a high degree of variability in model
solutions and any implications regarding snow potential are very
murky at this range. What can be said with confidence is that
it will be quite a bit cooler in the latter half of next week
behind the leading troughs, with current projections for
Wednesday to Friday showing daily highs in the 30s and overnight
lows around the mid-teens to lower 20s.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1125 AM CST Fri Nov 21 2025

VFR conditions are forecast through the TAF period. Low ceilings
that affected southern Iowa earlier today have moved into
Missouri. A few sprinkles are possible at DSM and OTM in the
next six hours, but restrictions to visibility are unlikely and
even if they do occur should be brief before clearing out this
evening.

&&

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

&&

$$

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