449 
FXUS63 KDMX 221756
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1156 AM CST Wed Nov 22 2023

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

.DISCUSSION.../Today through Tuesday/
Issued at 217 AM CST Wed Nov 22 2023

Key Messages:

- Warmer today, then cooling through Thanksgiving and the end of
  the week
- Chance (30-50%) for light snow Saturday evening into Sunday morning

Discussion:

Surface high pressure nudged into Iowa overnight, easing winds to 
under 10 mph across the state. This will continue to shift east 
today with associated thermal ridging resulting in good warm air 
advection into the area. This will send afternoon temperatures in
the upper 40s and low 50s which is near average for this time of 
year. This will be the warmest day in the forecast period and 
sadly short-lived and a temperatures slide through the end of the 
week. This is owed to a large low churning across Canada that 
will dampen the thermal ridge. While the rest of the week remains 
dry, temperatures by Thanksgiving day will be in the low 30s north
to low 40s south and on Friday highs will only crack the low to 
mid 30s areawide.

As this happens a trough across the western US will deepen as it 
swings east across the Rockies and into the central US. Consistency 
is increasing amongst guidance, but differences remain. Primarily, 
the GFS is favoring somewhat un-phased northern and southern 
lobes within the larger trough resulting in a drier area between 
two areas of light snow, along with much colder air filtering in 
behind the system as it wraps up and shifts east on Sunday. 
Meanwhile, the Euro solution maintains a broad swath of light snow
and open wave pattern with less cold air on departure. While this
lends to uncertainty, what we do know is that over 75% of 
ensemble members across both the Euro and GFS favor measurable 
snow across much of Iowa Saturday evening through Sunday morning. 
Accumulations are light, averaging around an inch. While this is 
minor, increased holiday travel and the first accumulating snow of
the season means that this could be impactful for those out on 
Sunday morning. 

The forecast remains cold and and dry into next week as a few 
passing shortwaves miss us with precipitation but help to reinforce 
to cooler air. High temperatures look to remain in the upper 30s to 
low 40s through at least the middle of next week.

&&

.AVIATION.../For the 18Z TAFS through 18Z Thursday afternoon/
Issued at 1155 AM CST Wed Nov 22 2023

Confidence is high that VFR conditions will persist through the
period with nothing beyond variable high level cloudiness. Brisk
SSW winds this afternoon will diminish somewhat tonight as winds
veer to westerly overnight, and then northerly into Thanksgiving 
morning with the passage of a trough and subsequent cold front. 
There may be a brief period of LLWS east tonight at KALO and KOTM
just ahead of the trough passage.

&&

.DMX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

$$

DISCUSSION...Hagenhoff
AVIATION...Small