National Weather Service Raw Text Product

038 
FXUS63 KDMX 212107
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
307 PM CST Fri Jan 21 2022

.DISCUSSION.../Tonight through Friday/
Issued at 304 PM CST Fri Jan 21 2022

Key Messages:

-
-

Tonight thru Monday -
Arctic high pressure has moved off to the east today with return 
flow bringing warmer albeit still well below normal temperatures to 
the Iowa this afternoon. A short wave trough is moving into the 
western Dakotas this afternoon and is preceded by a surface trough 
that extends across the far eastern Dakotas and into central 
Nebraska. A band of light snow that has formed in the warm advection 
aloft, is moving ahead of the surface trough and will move across 
Iowa overnight. The moisture band associated with the light snow is 
relatively narrow so the residence time of any snow will be short. 
Still snow accumulations around an inch could occur over far northern 
Iowa and possibly a half inch south into the Des Moines metro. Mild 
westerly downslope flow is occurring behind the trough and that will 
allow temperatures to slowly rise for much of the overnight before a 
shift to more northwesterly winds occur late. It is possible that 
the overnight lows will occur at 6 pm this evening. Expect gusty 
winds in advance of the trough then gradually diminishing overnight.

The active northwest flow will persist this weekend. A brief lull 
during the day Saturday with a wide range in temperatures by the 
afternoon with teens northeast to the low 30s southwest. A clipper 
will dive southeast by Saturday afternoon and will bring light snow 
chances to far north central Iowa by late afternoon then move across 
the region Saturday night. Still some minor variability on the 
surface low track with this system. Proximity soundings suggest a 
period of a deep dendritic layer that may push snow ratios to near 20 
to 1 at times. Overall, this system could bring 1 to 3 inches of 
snow along the northeast quadrant of the surface low track, which is 
focused on the northeast 1/3 to 1/2 of Iowa. Should a bit more 
moisture become available and snow ratios remain high, a few 
locations could see upwards of 4 inches. 

High pressure will move across Iowa on Sunday and there could be a 
few periods with sunshine, especially early in the day assuming the 
lingering stratus from the Saturday night system clears. Mid-level 
cloudiness will be on the increase during the afternoon in advance 
of the next system. That area of low pressure does look to remain 
confined over Minnesota and Wisconsin along with most of the 
precipitation chances. The deterministic NAM is hinting at perhaps a 
mix of freezing rain and snow Sunday evening but at this point, this 
chance of this scenario appears low. The area of low pressure will 
move east Sunday night and Monday. Monday morning will start warm 
before the Arctic boundary moves across the state by the afternoon.
Donavon

Extended Period(Monday night thru Friday)- 
A broad area of high pressure brings another blast of Arctic air 
across the upper Midwest Monday night through Wednesday, with the 
Arctic air further reinforced by the Hudson Bay low. Bitter cold 
temperatures with northwesterly flow aloft is expected, though 
nothing in the way of precipitation through midweek is expected 
for further consideration at this time. The main focus through 
this period are temperatures, coldest Tuesday night into Wednesday
morning with values well below zero across most of Iowa, where 
wind chill headlines will be likely. As the high departs Thursday 
and flow aloft shifts southwesterly, warmer temperatures for the 
season return in the 20s through the 30s. Falling heights with an 
eastward tracking shortwave trough suggests a chance for light 
snow showers across the majority of Iowa through Thursday into 
early Friday. A short lived high pressure system follows Friday as
it sinks down into the Midwest, bringing returning dry weather. 
Model guidance suggests little change with temperatures into the 
weekend, with highest temperatures holding out in the 20s to 30s. 
Bury

&&

.AVIATION.../For the 18Z TAFS through 18Z Saturday afternoon/
Issued at 1144 AM CST Fri Jan 21 2022

VFR conditions are expected through the afternoon across the
terminals. Breezy winds with periods of spotty LLWS may occur through
early Saturday before winds shift back to the northwest. Clouds 
will increase with light snow showers across most if not all 
terminals this evening, which will come with periods of reduced
visibilities. Ceilings are expected to decrease with MVFR 
conditions, along with brief periods of IFR possible across the 
KMCW, KALO, and KFOD terminals after 03z tonight through early 
Saturday morning. Improving conditions follow as the system 
departs late Saturday morning.

&&

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

$$

DISCUSSION...Donavon/Bury
AVIATION...Bury/Donavon