000
FXUS63 KDMX 170553
AFDDMX

Area Forecast Discussion
National Weather Service Des Moines IA
1153 PM CST Sat Jan 16 2021

...Updated Aviation Discussion...

.DISCUSSION.../Tonight through Saturday/
Issued at 237 PM CST Sat Jan 16 2021

Take Home Points:

*Seasonable temperatures
*Periodic light winter precipitation chances over the next few
 days

Discussion:

After an eventful, if not unusual, end to the work week, conditions
quieted down overnight as upper low continued to shift eastward
across the southern Great Lakes Region. Locally, stratus remained
supplanted over the area amidst northwest flow, CAA, and weak
subsidence. A few sporadic areas of light freezing drizzle were seen
through the day, but nothing pervasive or widespread enough for
concern or inclusion into the prevailing forecast.

Over the next 48 to 72 hours, multiple shortwaves are expected to
traverse the region and have resulted in relatively broad brushed
PoPs within the forecast due to discrepancies in both placement and
timing. The opportunity of greatest confidence occurs this
evening/overnight as a shortwave currently situated over central
South Dakota, and viewed well on WV imagery, continues to slide SE.
Best light snowfall opportunities will be across roughly the
eastern third of the state, yielding up to around a half inch or
less in far eastern portions of the forecast area and amounts up
to around an inch outside of the forecast area to the E/SE.
Opportunities for additional light snowfall outside the hi-res
windows Sunday through Monday continue to struggle to find overall
consistency in placement and timing within guidance. NBM tends to
reflect this as well as it continued its trend of coming in dry
throughout that time period. Digesting the ensemble guidance,
roughly half the members depict light precipitation and depending
on your parent model of choice, location and timing vary. There is
reasonable confidence in light winter precipitation, but a lack
of confidence in the details so did add back in the aforementioned
relatively broadbrushed PoPs in coordination with neighbors.

Into the week, the overall pattern looks to return to a semblance of
split flow with the majority of impactful waves remaining N/S of the
area. That isn`t to say additional short waves aren`t going to slide
through, simply that their depictions within synoptic guidance are
not well coordinated and there is no need to paint in additional
broad low end, limited confidence PoPs at this time. A brief period
of warming will be seen mid-week as the northwest steering flow
gives way to height rises and subtle ridging, yielding temperatures
likely back into above freezing territory for highs for much of the
area Wednesday and Thursday. A cold front then slides through to end
the week and drops highs back into the 20s to end the week and
potentially widespread lows into the single digits.

&&

.AVIATION.../For the 06Z TAFS through 06Z Sunday night/
Issued at 1141 PM CST Sat Jan 16 2021

MVFR ceilings to persist over central Iowa until Sunday night with
intermittent IFR ceilings possible overnight. However, there is a
break in the MVFR stratus at FOD and further north upstream which
may impact DSM by the early morning hours. Left with the
persistent MVFR ceilings for now as they remain fairly steady just
east of FOD. ALO to see light snow for a few hours tonight
producing IFR visibility at times.

&&

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

&&

$$

DISCUSSION...Curtis
AVIATION...Podrazik

NWS DMX Office Area Forecast Discussion