Cedar, Iowa Weather Forecast Discussion

228
FXUS63 KDMX 110734
AFDDMX
Area Forecast Discussion
National Weather Service Des Moines IA
234 AM CDT Thu Sep 11 2025
.KEY MESSAGES...
- Patchy fog across northern Iowa this morning.
- Warming trend today through early next week with highs in the
  upper 80s to low 90s.
- Precipitation chances return late Sunday into Monday.
&&
.UPDATE...
Issued at 234 AM CDT Thu Sep 11 2025
Patchy light fog has developed across southern Minnesota, Wisconsin,
and parts of northeast Iowa early this morning. Dense fog has
largely been confined to river valleys and low lying areas as
evidenced by GOES nighttime microphysics imagery. So far this
morning the only site within the CWA to drop under a mile has
been Mason City with observations that have several times
bounced from 10 miles to 1/4 mile and back. DOT road cameras
(in lighted areas) show that the fog is spatially fairly patchy.
Should conditions become more consistent and/or widespread an
advisory may be needed.
Thermal ridging builds into the area today, pushing temperatures
into the mid to upper 80s. As we move into the weekend warming
increases, pushing the upper 80s to low 90s across the area. The
GFS remains over mixed, as has been discussed several times
over the past several days. Along with that, a western US trough
will deepen through the weekend with a few ridge rider
shortwaves that try to pass across the area. The chances of
these producing precipitation is quite low with soundings
showing significant dry air to overcome, however some cloud
cover is possible, especially towards northern Iowa. With over
mixing in the GFS and the potential for scattered cloud cover
this weekend, have continued the trend of the past several days
and have nudged temperatures down from the deterministic NBM
guidance.
Better precipitation chances arrive by late Sunday into Monday when
the trough finally makes it to the central US.
&&
.DISCUSSION...
Issued at 242 PM CDT Wed Sep 10 2025
Upper level ridge continues to nudge eastward today through Sunday
as the western upper trough begins to move through the western U.S.
through the first part of the weekend. Main result will be a
continued dry and increasingly warmer forecast over the next several
days as the thermal ridge nudges further east with each passing day.
Saturday looks to be the warmest day though temperatures in the 80s
to nearing 90 round out the week before upper 80s to low to mid 90s
are forecast for the weekend. With dew points `only` into the 60s,
heat indices won`t be as high as heat events earlier this summer,
but it will certainly be a warm end of week and weekend for
especially any with outdoor interests. The extent of the heat does
remain the primary forecast challenge through the weekend though
with a combination of the warm bias GFS/GEFS and related overmixing
sending NBM temperatures to the upper ends of the temperature
distribution, meanwhile nearby shortwave energy rounding the ridge
and increasing mid to upper level moisture will bring clouds into
play at times. As has been done for the last several forecast
cycles, continued to bring max temperatures down from NBM towards
the 50th percentile, but further fine-tuning is likely with cloud
cover potentially spoiling temperatures in some places.
In the shorter term, patchy fog will once again be possible late
tonight into early Thursday, especially in northern Iowa. Upper
level smoke will also continue to filter into the area through at
least much of the daytime Thursday keeping skies hazy. As noted
above, precipitation will be hard to come by for the next several
days. Although CAMs, and to a lesser extent some global models, do
try to kick off some scattered activity into early Friday with the
nearby shortwave, forecast soundings would suggest cloud cover vs.
precipitation reaching the ground with dry low levels in place. The
better chances arrive Sunday night into Monday as the upper trough
arrives in the region with details to be fine-tuned over the coming
days.
&&
.AVIATION /06Z TAFS THROUGH 06Z FRIDAY/...
Issued at 1029 PM CDT Wed Sep 10 2025
VFR conditions late this evening and into the early morning
hours, with light and variable winds. Patchy fog is still
expected to develop through the morning, mainly over northern
Iowa. KMCW continues to have the highest probability for
impacts, but have included 6SM BR to KFOD and KALO during the
most likely time for at least patchy, shallow fog. Fog will
dissipate after sunrise, giving way to light east to
southeasterly winds and VFR conditions tomorrow.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Hagenhoff
DISCUSSION...05
AVIATION...Dodson

NWS DMX Office Area Forecast Discussion