634
FXUS63 KDMX 231739
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1139 AM CST Sun Feb 23 2025

 ...Updated for the 18z Aviation Discussion...

.KEY MESSAGES...

- Warming persists into the early portion of the week.

- A few showers in northern Iowa late Monday afternoon into
  evening with 20-30% coverage.

- Slightly higher chances for precipitation Tuesday night into
  early Wednesday (30-50%) with a pause in warming on Wednesday.

&&

.DISCUSSION...
Issued at 244 AM CST Sun Feb 23 2025

A weak shortwave is approaching Iowa from the northwest early this
morning with mid and high level clouds spreading over the state. Low
level moisture remains very limited, therefore the biggest impact
will be from the clouds as the push overhead during the morning.
However, the system scoots to the southeast by this afternoon with
sunshine returning as warm advection continues through the day.
Highs over-performed in areas without snow cover yesterday and
see no reason this trend should not happen once again today.
Therefore, readings in the northwest and southeast where snow
cover is very limited or non-existent have been bumped well
above guidance. Even areas with snow cover should beat guidance
as the snowpack shrinks quickly through the day.

A bit more robust shortwave approaches the state on Monday into
Monday evening in the fast WNW flow aloft.  Clouds are likely to
spill into the state during the day in advance of the system which
limits insolation and provides a bit more difficulty in determining
highs.  The snowpack is also likely to be much smaller in area and
much of it is expected to be gone by the end of the day on Monday.
Have continued with even warmer temperatures on as the thermal ridge
passes through the state but with the knowledge of increasing clouds
which may skewer highs. Forcing increases across the north by
later in the afternoon and into the evening as the shortwave
approaches. Once again, low level moisture is limited as the
overall flow is from the west with little Gulf moisture
involved. A few showers (20- 30% coverage) may pass across the
north during this time but impacts remain limited.

A brief shot of cold advection follow Monday night into early
Tuesday but is quickly replaced by warm advection later Tuesday in
response to the next approaching shortwave.  Above normal readings
are once again expected given the increasing south flow during the
day and relatively sunny conditions and remained on the high side of
guidance.  Increasing theta-e advection into Tuesday night and early
Wednesday is expected to lead to scattered shower activity into the
state.  GFS and Canadian are quite robust with coverage whilst the
other model output is a bit more reserved.  This is partly due to a
better tap into Gulf moisture in the GFS/Canadian vs the other
output.  Have generally gone with a 30-50% coverage of showers later
Tuesday night into Wednesday morning when lift is maximized across
the state.  This may get bumped if the wetter solutions become more
likely.  Cooler temperatures but still above normal are expected on
Wednesday with weak cold advection into the state, however warming
then ensues once again to end the work week with readings staying
well above normal.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1138 AM CST Sun Feb 23 2025

Main concern will be wind shear potential overnight as winds
aloft increase between ~05 and 12z. Trough will pass east of
region aft 12z with westerly flow remaining. VFR conditions
expected during period with high clouds from funneling into
region from the Dakotas. /rev

&&

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

&&

$$

DISCUSSION...Cogil
AVIATION...REV