Altoona, Iowa 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

906
FXUS63 KDMX 142333
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
533 PM CST Wed Jan 14 2026

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

.KEY MESSAGES...

- Light snow possible on Thursday.

- Snow showers or squalls possible Friday as another cold front
  arrives. Windy at times.

- Cold this week and light snow chances may persist.

&&

.DISCUSSION...
Issued at 1247 PM CST Wed Jan 14 2026

The morning strato-cumulus is eroding early this afternoon as the
available moisture continues to thin across Iowa much drier air
filters into the state today. Recall, this is the dry air that was
near the International border yesterday afternoon. Gusty winds
remain across the state as well though they are diminishing from
north to south as the mixed layer winds subside. Expect much of the
gusts to subside by early this evening with parts of southern Iowa
not loosing mixing until a few hours after sunset.

A ridge of high pressure will move across Iowa from west to east
tonight with the main high pressure center shifting to the south
over Oklahoma and Texas. Upper level theta-e advection will be
overtopping the surface feature by 06z with the lower level theta-e
advection lagging a bit and arriving late tonight into Thursday
morning. The initial clouds should be overtopping the light and
variable area along the ridge which is separating the northwest
winds to the return flow to the west and should minimize the low
temperature drop overnight. Steady to rising temperatures will then
follow over the west as that return flow arrives. Light snow is
expected to develop Thursday morning as kinematic forcing from an
approaching short wave moves over the region of strong theta-e
advection. There remains some moisture discontinuity with this
system which is leading to various solutions amongst the
deterministic solutions and just blending these together isn`t
necessarily a good solution either. Overall, there will be light
snow but it may be more in showery form as compared to a broad area.
The moisture discontinuity is also leading to temporal differences
but overall the will be the initial round in the morning/afternoon
followed by mid-level drying followed by another round Thursday
night as the next short wave arrives. At this time, any
accumulations should be an inch or less.

We continue to monitor the snow shower/squall potenitial late
Thursday night into Friday. A trough of low pressure moving through
Thursday night will lower dew point values over the area ahead of
the main cold front that is on track to arrive Friday afternoon.
These dew points are a bit lower than expected 24 hrs ago and may
have some impact on the snow shower/squall potential, especially
over southern Iowa. The snow squall parameter utilizing the original
0-2 km layer, is still showing unstable surface based CAPE and low
level shear as the frontogenesis arrives with the more Arctic like
airmass in the afternoon. This should result in the development snow
showers and if enough moisture depth is achieved, snow squalls. More
shallow horizontal convective rolls may follow into the evening.
Travel impacts remain possible on Friday and worst case scenario,
could have significant impacts. At the very least, gusty winds are
expected and may require headlines as well.

The NBM continues to play catchup with high temperatures Saturday as
-20C to -25C 850 mb temperatures move over central Iowa. The
 overnight NBM run dropped temperatures another 4 degrees from
 the previous NBM run utilized in grids yesterday. For
 reference, CONSRaw is running 2 to 4 degrees colder than the
 NBM, which has bias corrected input. CONSRaw will be closer to
 reality. Periods of light snow may also persist as the cloud
 layer will fall into the dendritic growth zone. The next surge
 of cold advection arrives Sunday and Sunday night and will
 bring another period of light snow and gusty wind potenitial.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 533 PM CST Wed Jan 14 2026

Breezy winds are beginning to diminish in northern and eastern
Iowa but gusts of 20-25+ kts will persist into the night at
sites KALO/KDSM/KOTM before tapering off overnight. Winds on
Thursday morning shift to out of the south with increasing cloud
cover. Light snow is possible, mainly at northern sites
KFOD/KMCW/KALO, however with dry air in place confidence is low
and any ocarinas should be light. As such, have retained the
prob30 group mention.

&&

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

&&

$$

DISCUSSION...Donavon
AVIATION...Hagenhoff