Mason City, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

925
FXUS63 KDMX 040859
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
359 AM CDT Mon May 4 2026

.KEY MESSAGES...

- Warm and breezy today, but with a cold front pushing through
  this afternoon and evening. A few strong to severe
  thunderstorms will be possible along the front this evening in
  southeast Iowa.

- Breezy winds and potential light showers behind the cold front
  this evening over north-central to central Iowa, lingering
  south into early Tuesday morning.

- Cooler weather from Tuesday into Thursday, with another
  frost/freeze possible in parts of Iowa into Wednesday morning.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 359 AM CDT Mon May 4 2026

Mild and dry conditions persist across Iowa early this morning, with
light south/southwesterly winds keeping most areas on the warmer
side in the upper 40s to low 50s, despite mostly clear skies across
the area. Upper level clouds however are noted further north into
Minnesota per satellite imagery, given the presence of moisture in
this layer, which will gradually shift southward into Iowa
later today. Through the rest of this morning, southwest flow
and increasing theta-e advection will spread into Iowa,
especially across the south. Temperatures as a result will
easily soar through the 70s over northern to north central Iowa,
and into the low 80s for much of central Iowa by this
afternoon, paired with dewpoints in the 40s to low 50s, highest
south. The main feature of focus today otherwise will be a
defined cold front, currently seen draped across southern North
Dakota into northern Minnesota that is expected to make its way
into Iowa later today. This feature is associated with a
deepening area of strong low pressure over southern Ontario,
which will continue to depart slowly eastward through today.
With the influence of this system felt over northern Iowa this
morning in particular, an area of localized strong 850mb winds
over this area may mix down occasionally, with gusts up to 25-35
mph at times before decreasing by the afternoon. Regarding
timing of the surface front across Iowa today, expectations per
latest guidance has this boundary arriving into northwest Iowa
around 11am-12pm, drifting south/southeast through about 9-10 pm
when it will then exit the state. As this front passes
overhead, dry conditions are expected to largely persist through
the afternoon, given the presence of a pronounced layer of near
surface dry air and capping overhead. By the early evening
though, showers and storms are expected to develop along and
ahead of the boundary, particularly over southeast Iowa.
However, trends continue to indicate the front into northern
Missouri before storms even develop, which is something that
will need to continue being monitored. Overall, environmental
parameters into southeast Iowa are characterized by instability
values around 1500 J/kg, shear of 35-40 knots, along with steep
lapse rates around 8 C/km and DCAPE values around 1000-1200
J/kg, which would point to favorable storm development and
maturity to produce large hail and even more so damaging winds,
especially considering the aforementioned low level dry air that
is still indicated per soundings to be overhead. This overall
risk is conditional though, given lingering uncertainty on the
exact location of the front this evening and overall moisture
availability. The Marginal Risk remains over the southeast half
of Iowa per SPC to highlight this remaining potential.

Outside of the potential risk for storms, there remains a signal for
winds to pick up behind the surface cold front as the elevated
boundary follows it, with models such as the HRRR showing brisk
winds gusting to 25-35 mph by late in the afternoon and through the
evening. CAMS continue to indicate a swath of light reflectivities
in relation to the elevated front passing through into the evening
which will keep lingering chances for light rain showers in the
forecast until early Tuesday morning. Very little impact is expected
as any QPF output would be very light. Temperatures behind the
surface front will fall through the evening and overnight, with
northerly flow advecting cooler air across the state. Overnight lows
are expected to fall into the upper 30s to upper 40s, coldest over
northern Iowa. A broad area of high pressure will spread across the
Midwest region Tuesday, with drier and cooler air remaining
overhead. Winds out of the northwest will be common, along with
highs topping out in the upper 50s to low 60s, warmest south.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
Issued at 359 AM CDT Mon May 4 2026

The overall pattern through midweek changes little, with broad
troughing across the Midwest and weak but broad high pressure over
the area keeping conditions on the dry and cool side. Potential
for frost/freeze is increasing mainly over northern to north
central Iowa Tuesday night/Wednesday, with headlines certainly
possible during this time but will need to monitor potential
lingering clouds and light winds over the area that would
overall limit frost formation from occurring. By Thursday, this
trough finally begins to depart to the east, with an area of
mid-level ridging to the west. A very low potential (<15%) for
light rain is signaled over northeast Iowa later in the day with
another shortwave passing southeast within the larger flow,
though the better forcing and moisture is confined further east
into WI at this time. The region will otherwise experience
gradually warming conditions as a result of low level flow
returning back from the west/southwest that will lead to highs
back into the 60s through Friday. Low rain chances (<20%) return
again over southern Iowa Friday, with otherwise dry and warmer
conditions largely remaining into the start of the upcoming
weekend.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1042 PM CDT Sun May 3 2026

VFR conditions prevail through much of the TAF period. Light and
variable winds this morning will increase out of the southwest
after sunrise. A front dropping north to south through the area
will lead to increased winds and changing directions through
the day. Winds become westerly just ahead of the front, then
northerly behind. Winds will generally gust to around 20 to 25
kts, with sporadically higher gusts near 30 kts possible. A few
showers and/or thunderstorms are possible along the front in the
late afternoon and evening, but this threat looks to be
primarily over KOTM and southeast. Winds remain breezy into the
evening, before diminishing overnight.

&&

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

&&

$$

SHORT TERM...Bury
LONG TERM...Bury
AVIATION...Dodson