Mason City, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

150
FXUS63 KDMX 191143
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
643 AM CDT Thu Mar 19 2026

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

.KEY MESSAGES...

- Patchy to localized dense fog remains possible over northern
  Iowa through mid-morning before dissipating.

- Warming trend continues into the weekend, topping out on
  Saturday well above average values in 70s to 80s. Elevated
  fire weather conditions are expected.

- Brief cooldown on Sunday with recovering temperatures to start
  next week. Forecast looks largely dry into early next week.

&&

.SHORT TERM /THROUGH FRIDAY NIGHT/...
Issued at 332 AM CDT Thu Mar 19 2026

Fairly quiet conditions are noted across Iowa this morning, with
satellite imagery depicting recently clearing skies over the
northern half of Iowa, while southern Iowa remains covered but
should also clear out as clouds descend further out of the state
over the next hour or so. This has resulted in a notable temperature
gradient, with values in northern Iowa in the 30s to low 40s, while
southern Iowa has values in the upper 40s to low 50s. Should see
temperatures decrease and become a bit more uniform through sunrise,
with lows through the 30s. Fog so far has been quite isolated but
also inconsistent over northern Iowa, with areas such as Mason City
bouncing between 1/4 to 3 statute miles in visibility, while other
sites nearby have read values of 2-6 miles before returning back to
10 miles with no fog. Model soundings, especially the NAM, continue
to show notable moisture trapped under the inversion that is
covering the state this morning, but is likely a bit overdone as the
snow cover over much of the area has largely, if not completely
melted due to the above freezing temperatures. HREF guidance has
backed off only slightly, with patchy fog still suggested over the
northern half of Iowa, but with only isolated areas of dense fog
near the IA/MN border where better moisture content is most likely
to remain, peaking around or just after sunrise before dissipating
mid-morning. Given the uncertainty on the extent of fog this
morning, will be holding off on any potential headlines, though
close monitoring will continue through the rest of the morning.

Northwesterly flow aloft over Iowa due to the building mid-level
ridge over the northwestern CONUS will prevail today, and largely
remain through the next few days, keeping the region on the dry side
into the weekend. Mostly clear skies are expected, which will allow
for temperatures to warm up quickly as highs reach into the 60s to
low 70s, warmest southwest, though a bit cooler northeast in the 50s
where lingering snowpack still remains but will continue to melt.
A mid-level trough riding the prevailing ridging pattern is still
expected to slide southeast into the Midwest late tonight into
Friday morning, though should remain well north and east of Iowa as
any forcing with this wave is indicated to largely reside over the
upper Great Lakes region. However, could see the potential for fog
again over portions of northern and eastern Iowa as CAM guidance is
hinting at another overnight inversion and lingering moisture at the
surface from snowmelt. This likely is already overdone as forecast
temperatures today should get rid of any remaining snow in these
areas and limit the extent of moisture that these models are trying
to pick up on. Regardless, something to keep an eye through today.
Overnight lows will fall into the 40s, highest south.

Surface high pressure slides into the region through Friday behind
the aforementioned northeastern trough passage, which will keep
conditions dry. Though winds will shift northwesterly for the day,
the push of warmer air aloft around 15 C (paired with subsidence
from the high pressure) and mostly sunny skies at least over the
southwest half of the state will boost highs in the 70s, while
cooler northeast where clouds are looking more likely keep values a
touch cooler in the 60s.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Issued at 332 AM CDT Thu Mar 19 2026

As the area of high pressure departs into Saturday, will see a shift
in low level winds increasing out of the southwest, which will bring
a stronger push of warm air advection into Iowa ahead of the
development of a broad area of low pressure over the western Central
Plains. With the warm front well north of Iowa, dry conditions will
prevail, with temperatures warming very nicely across the state
through the day, as well above average values in the 70s in the
northeast half of Iowa, and through the 80s in the southwest half
are likely. Breezy southwest winds with the push of warm and dry air
(RHs dropping in the 30s, lowest over southwest Iowa) and fuels
still cured will result in elevated fire weather conditions, but
should remain below headline criteria at this time. Burning is not
recommended.

By Sunday, the center of the low pressure mentioned above looks to
directly pass over Iowa to some degree, with the boundary dropping
southeastward across the Northern Plains. There are some differences
in the track of the warm front and therefore potential rain that
could come with this. The NAM and Euro favor at least some light
rain over northern Iowa while the GFS trends on the dry side. Winds
shift northwesterly through Iowa Sunday morning as cold air
advection pushes across the state, which will cool temperatures
through the morning. This means a non-diurnal trend in
temperatures at least over northern Iowa, so warmest temps in
the early morning and decreasing through the day. A large range
in temperatures are expected, with highs in the upper 40s to
50s north and in the 60s to low 70s south. Dry conditions remain
into the start of the next work week as high pressure sinks
across the region.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 642 AM CDT Thu Mar 19 2026

Localized dense fog over KMCW will continue at times over the
next few hours, leading to periods of reduced visibilites below
a mile. Patchy fog is expected otherwise at KFOD and KALO, but
should lift by mid-morning, with minor visibility restrictions.
Otherwise, mostly clear skies are expected, with VFR conditions
expected to return across all terminals. Winds out of the
north/northwest will be light, then shifting south/southwesterly
this evening into Friday and increasing.

&&

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

&&

$$

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