074
FXUS63 KDMX 011124
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
524 AM CST Sun Nov 1 2026

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

.KEY MESSAGES...

- Rain lifting by the end of the night with dry conditions
  remaining Sunday.

- Rain returns Sunday night. Marginal Risk for severe weather
  Monday afternoon.

- Rain remains likely through at least Wednesday.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 132 AM CDT Sun Nov 1 2026

A few lingering showers are traversing our northern and eastern
areas at the current time, and once those clear out the forecast
is dry through the day today. Weak mid-level ridging will move
overhead during the day supporting some thinning of the clouds
and there may even be a few breaks at times. This should also
allow temperatures to rise a little above yesterday`s levels,
though any warming will be mitigated by the remaining cloud
cover and relatively light nature of southeasterly breezes. Even
so, highs in the mid to upper 60s are forecast and it should be
a pleasant day overall.

A deep 500 MB trough will mover across the western CONUS today
and then over the Rockies tonight. The trough will be split into
several pieces with a northern stream component moving across
west central Canada, a southern component nearing the Four
Corners region by late tonight, and two leading shortwave
troughs moving northeastward over the High Plains tonight after
dark. The broad forcing for ascent associated with these leading
waves, overlying a swath of theta-e advection and in
conjunction with deep atmospheric moisture content, will promote
the development of a large area of showers that will move into
mainly western and northern portions of our forecast area after
midnight. However, even ahead of this slug of rain/showers,
within a broad warm air advection regime aloft there may be some
more isolated preceding shower development which is supported by
some hi-res model solutions such as the 00Z HRRR and FV3 runs.
In light of this potential, have added slight chance (20%) POPs
over about the western half of our area between 9 PM and
midnight tonight, leading into the more robust POPs later.

&&

.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 248 PM CDT Sat Oct 31 2026

The trough has closed northern and southern stream components
to it, which look to merge together over the region Monday
night. Ahead of then, the southern feature will mature as it
ejects into the Plains. The midlevel reflection of the jet will
round the trough base and cover the warm sector Monday
afternoon. 700mb temperatures have trended warmer in southern
Iowa, so lapse rates are closer to 7 C/km. MUCAPE values could
surpass 500 J/kg in far southern Iowa. A line of storms will
form along the cold front, but its threats will depend on how
much clearing can take place ahead of its arrival. REFS ensemble
soundings and hodographs have favorable shear parameters for
damaging winds and tornadoes, but are at the mercy of the lower
thermal profile. There is not much spread in the PBL temperature
values, which struggle to mix in most all ensemble members.
Without near-surface instability, the threat will be mainly
isolated damaging winds.

Another notable trend is the timing of the front arriving in
Iowa. This is because the two aforementioned components of the
trough will be merging together, causing the resultant closed
low to stall. The delayed arrival means severe weather chances
are lower, since storms would be arriving after dark. The slowed
movement then increases the rainfall amounts, as the front will
utilize the 1.5" PWATs and drop 1-2" in southern Iowa.
Something else we`ll need to watch is storm potential in eastern
Iowa on Tuesday afternoon due to the front`s late exit. That
said, the thermal profile looks less impressive on Tuesday, by
comparison. Cooler temperatures will advect in on the backside.
Precipitation chances linger through much of the week due to the
TROWAL of the system.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 524 AM CST Sun Nov 1 2026

Low clouds are producing IFR/LIFR/VLIFR ceilings across parts
of western Iowa early this morning; currently just west of FOD
and DSM but may impact those terminals in the next couple hours
before gradually moving out to the NW. Have included TEMPO
groups at FOD/DSM through 14Z, but amendments may be needed
this morning. Elsewhere, mainly VFR conditions are expected
through 18Z though there may be some brief BR. Later today more
widespread low ceilings will spread from south to north,
reaching OTM/DSM by around 18Z and the northern terminals later
this afternoon/evening. Thereafter, MVFR ceilings will prevail
and gradually lower to IFR tonight. Rain will then spread into
the area after 06Z and have included PROB30 groups at
FOD/MCW/DSM where it should arrive before 12Z Monday, but
timing and details for that period and beyond will be refined in
later TAF issuances.

&&

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

&&

$$

SHORT TERM...Lee
LONG TERM...Jimenez
AVIATION...Lee