516
FXUS63 KDMX 112345
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
645 PM CDT Mon May 11 2026

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

.KEY MESSAGES...

- Breezy winds increasing tonight into Tuesday. Sustained winds
  nearing 30 mph and gusts up to 40 mph could lead to erratic
  fire behavior, as well as blowing dust in rural areas.

- Scattered showers late tonight into mid-day Tuesday. A few
  rumbles of thunder are possible south Tuesday afternoon. A few
  gusty winds are possible but severe weather risk looks low.

- Warm temperatures expected through the week, with widespread
  shower and storms returning late Thursday into Friday.

&&

.SHORT TERM /THROUGH TUESDAY NIGHT/...
Issued at 251 PM CDT Mon May 11 2026

It`s been yet another day pleasant day across Iowa, as clear skies
complement the light winds beneath surface high pressure today.
Temperatures have warmed nicely just through insolation from the May
sun, putting temperatures in the mid 60s northeast to mid 70s
southwest. Farther south and west of the area, south southwesterly
winds have started to advect warmer air up into eastern Nebraska and
southeastern Iowa, leading to even warmer temperatures in the upper
70s to low 80s. As the surface high moves off later today and into
tonight, this warm air advection will begin to work it`s way into
Iowa, keeping temperatures warmer tonight and increasing into the
80s on Tuesday. This southwesterly return flow is a sign of the
upper level wave forecast to dive southeastward across the upper
Midwest tonight into Tuesday, dragging a weak boundary through the
area on Tuesday.

Surface pressure gradients tonight will respond to the incoming
shortwave, boosting winds overnight into Tuesday. While an inversion
does set up tonight, the tighter pressure gradients will still allow
for breezy sustained winds around 15 to 20 mph overnight with
occasional gusts up to 30 mph possible. However, the strongest winds
will develop as the boundary layer mixes out and surface boundary
passed through during the day on Tuesday. The environment is
checking many of the boxes for efficient wind production on Tuesday;
a deeply mixed boundary layer, tight pressure gradients, and very
dry conditions. Behind the boundary, moderate cold air advection
will also help with downward momentum transfer of winds, as well as
produce impressively uniform and unidirectional flow throughout the
mixed layer. In fact, the RAP and GFS show 30+ kt winds through the
entire boundary layer, barring the wind right at the surface,
resulting in a layer mean of around 32 kts. In other words, there
will be quite a bit of momentum through a deep layer just above the
surface, which likely won`t be as affected by surface friction as
the model may indicate with it`s depicted surface winds. Likewise,
NBM probabilities indicate a roughly 50 to 60 percent chance of 30
mph or greater winds through Tuesday afternoon, with a one hour
bullseye of 70 percent or greater near Estherville. Northern Iowa is
where the strongest winds are expected, but similar profiles (albeit
to lesser magnitudes) are in place throughout the state. This
indicates fairly good confidence in breezy sustained winds on
Tuesday afternoon, which will be flirting with wind advisory
criteria over northern Iowa. Gusts could approach advisory criteria
as well, but the lack of any really strong (40 kt+) winds in the
mixed layer implies the top end may not be as high. Therefore, only
expecting gusts up to 40 mph based on current guidance.

With the windy, warm and dry conditions Tuesday, there will be some
concern for erratic fire behavior, although fuels should be green
enough to limit significant concerns for uncontrolled fire spread.
Another, less common hazard (for Iowa) tomorrow is the potential for
pockets of blowing dust, especially in more open, rural areas. Crops
in the fields aren`t too far along yet, and soils are loose and
likely very dry given conditions from the last few days. Therefore,
the sustained winds near or exceeding 30 mph could very well pick up
dust from fields and result in pockets of lower visibilities through
Tuesday afternoon.

In addition to the winds around this system, we are also still
looking at chances for some scattered showers starting north late
tonight and dropping south and eastward through Tuesday. The main
source of forcing looks to stay to our north and east, meaning the
best synoptic ascent will be over northeastern Iowa Tuesday morning.
Moisture availability still seems to be the main limiting factor for
rain in northern Iowa Tuesday morning. We will have increasing gulf
moisture, but the antecedent conditions are very dry and will
requires some top down saturation to reach the surface. NBM still
isn`t overly convinced in rain chances, so have continued to boost
precipitation chances in the forecast above NBM guidance, just given
the lift through the saturated layer aloft. The upper level wave
will track eastward away from the state through the day Tuesday,
taking the synoptic support with it, although high resolution
guidance continues to produce at least light reflectivity along the
boundary/trough. Model soundings show good mid-level saturation, but
very dry low levels, suggesting hydrometeors will evaporate before
reaching the surface. Lift will also be dependent on weak lift
aloft, as the low level convergence along the surface boundary will
be fairly weak. With the saturation aloft, can`t rule out a few
drops squeaking through the dry layer, but confidence is pretty
low in measurable precipitation. Therefore, have kept PoP
chances around 15 to 20% for areas over central and southern
Iowa through mid-day Tuesday. A small stripe of instability does
still try to develop in southeastern Iowa, but only amounts to
at most 1000 J/kg. Therefore, the threat for severe weather
looks low, but can`t rule out a rumble of thunder and maybe some
gusty winds if any showers/storms overperform.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Issued at 251 PM CDT Mon May 11 2026

Milder air fills in behind the boundary Tuesday night into
Wednesday, but upper level ridging quickly builds eastward into the
state through mid-week. Temperatures will still reach the 70s under
the surface high pressure on Wednesday, then into the 80s as
southerly flow returns under the thermal ridge on Thursday. The 500
mb ridging will be abbreviated, though, as another 500 mb trough
quickly begins to move in on the backside of the ridge late Thursday
into Friday. This will open the state back up to a slug of gulf
moisture, with broad warm, moist air advecting into the state and
bring the return of shower and thunderstorm chances Thursday night
into Friday. Instability will be present on Friday afternoon, which
could lead to some stronger storms, although wind fields look less
impressive at this time range. Will better assess severe threat in
the coming days. The pattern looks to remain active and warm through
the weekend as well.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 641 PM CDT Mon May 11 2026

VFR to prevail through the period, maintained Prob30 groups for
showers, however impacts will be little to none. LLWS expected
overnight, strongest at KFOD and KDSM. Winds will elevate
overnight and still thinking gusts will be sporadic until
sunrise when gusts are highest. Winds will shift through the
day. Sustained winds are closer to the gust value, those gust
values being very frequent during the afternoon hours.

&&

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

&&

$$

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