Area Forecast Discussion
Issued by NWS Des Moines, IA

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FXUS63 KDMX 011951

Area Forecast Discussion
National Weather Service Des Moines IA
251 PM CDT Sun Oct 1 2023

.DISCUSSION.../Tonight through Sunday/
Issued at 248 PM CDT Sun Oct 1 2023

Key Messages:

- Record high temperatures continue today; Remains unseasonably
  warm through Tuesday
- Cool front Tuesday night into Wednesday
  brings breezy winds, cooler temperatures and shower/storm

Copy yesterday`s forecast and paste it onto today, because it has
been more of the same across Iowa. Still sitting under the upper
level ridge, Iowa has surface low pressure to the west and high
pressure to the east, resulting in warm southerly flow over the
state. Comparing observations from yesterday to today shows a
similar temperature trend as of 2pm for most climate sites, albeit
with much lower dew points. Waterloo has broken another daily high
temperature record while other sites still remain a few degrees off
of their records for the day. Efficient mixing over the area has
also resulted in breezy winds, especially in northern and western
Iowa where the pressure gradient is tighter nearer to the surface
low. Gusts over 25 mph have been observed at times this morning,
with a more consistent signal of 15 to 20 mph area-wide.

The unseasonably warm, near-record temperatures continue into the
work week as well, as the high pressure remains in place overhead
through most of Tuesday. The upper level trough to the west will
slowly inch its way closer to the state, which will translate to
surface low pressure intensifying out west and pressure gradients
continuing to tighten, causing gusty conditions on Tuesday. As the
boundary layer mixes out, wind gusts up to 30 mph are possible in
the afternoon, with the potential for gusts up to 35 mph in the
northwest. Winds will likely linger into the evening as well with
breezy winds and cold air advection along an associated cold

The surface low will lift northeast across the Dakotas and into
Minnesota, dragging the cold front behind it. This front will bring
cooler temperatures and precipitation chances to the area starting
Tuesday night and lasting into Wednesday. Much of the show along
this front looks to be west of the state Tuesday afternoon where the
more favorable environment resides. As the surface low tracks north
northeast and the front drifts into our area Tuesday night, dry air
will begin to cut off the moisture present along the front. This, in
conjunction with diminishing instability overnight, will limit
shower and storm chances the further east the front tracks.
Therefore, the best rainfall chances will be over the western
portions of the area where residual convection leaks into before the
instability and moisture diminish, while only a few scattered
showers and occasional storms will be expected further east.

Later Wednesday, the front will have made its way into eastern Iowa
and looks to reactivate over the far southern and eastern portions
of our forecast area. Instability looks underwhelming Wednesday
afternoon, but there will be a decent amount of shear in place. If
an updraft can become strong enough to balance with the shear, a
storm or two would certainly be possible in these areas, but tough
to get too excited with MUCAPE <1000 J/kg.

Unfortunately, after Wednesday, our dry spell resumes through the
rest of the week. Behind the front, north northwesterly flow will
lead to primarily cold air advection over the area. This will bring
temperatures back down to more seasonal values Wednesday and
Thursday before a shortwave brings another push of cold air late
Thursday night into Friday. Highs Friday and Saturday look to only
reach the 50s and 60s with overnight lows potentially falling into
the 30s and 40s. General cold air advection and multiple waves
passing through will result in breezy conditions through the second
half of the week as well.


.AVIATION.../For the 18Z TAFS through 18Z Monday afternoon/
Issued at 1222 PM CDT Sun Oct 1 2023

VFR conditions prevail through the period. Only impacts will be
breezy winds out of the south today, mainly at the northern sites
(KALO, KMCW, KFOD). Winds will diminish this evening.


Issued at 248 PM CDT Sun Oct 1 2023

Record High Temperatures for October 1 (Today/Sunday)

City - Record High Temperature - Year of Record

Des Moines - 92F - 1976
Waterloo - 93F - 2023* (Prev: 91F - 1897)
Mason City - 92F - 1976
Ottumwa - 94F - 1937
Lamoni - 91F - 1897

*High temperatures as of 2pm. Official records will be posted this

Record High Temperatures for October 2 (Monday)

City - Record High Temperature - Year of Record

Des Moines - 92F - 1953
Waterloo - 93F - 1953
Mason City - 92F - 1997
Ottumwa - 93F - 1953
Lamoni - 94F - 1953




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