614
FXUS63 KDVN 092058
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
258 PM CST Tue Dec 9 2025

.KEY MESSAGES...

- Freezing rain possible this evening, mainly along/north of
  Highway 20.

- Windy conditions tonight/Wednesday with peak gusts between
  45-55 mph. A period of light snow and even some heavier snow
  showers may accompany the strong winds leading to reductions
  in visibility.

- Additional clipper systems will likely result in periods of
  accumulating snow Thursday through Sunday.

- Temperatures will drop for the weekend with wind chills well
  below zero Friday and Saturday night.

&&

.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 230 PM CST Tue Dec 9 2025

This Evening into Early Tonight: SPC mesoanalysis had a strong
surface low over eastern North Dakota with mild southerly flow
downstream across portions of the Midwest, including Iowa and
Illinois. Locally, the freezing line has made it up to the
Highway 30 corridor with temperatures in the lower 30s north to
mid 30s - near 40s south. Warm air advection will continue into
this evening and tonight with steady SW to W surface winds.
Therefore, anticipate all locations to eventually rise above
freezing and hold in the 30s and 40s until a strong cold front
comes rushing through the area late tonight. Have maintained the
Winter Weather Advisory for the counties along/north of Highway
30 with the surface wet-bulb 32 F isotherm set up a bit further
south than the ambient temperature. It does appear that the
most likely area for a brief window of freezing rain is
along/north of the Highway 20 corridor where the surface wet-
bulb may not warm above freezing until closer to 9 PM tonight.

Late Tonight into Wednesday: As the surface low tracks into
Lower Michigan and deepens to around 988mb, it will drag a
strong cold front through the region leading to very windy
conditions with a tight pressure gradient over the area.
Momentum transfer supports widespread gusts between 40 to 50
mph, with some potential for 55+ mph favored west and southwest
of the Quad Cities. While it does look like there will be an
area of wrap around light snow late tonight into early Wednesday
morning, sweeping from north to south through parts of the
area, there is also potential for moderate to heavy snow showers
along the front. Confidence is low on the heavier snow
shower/squall scenario with recent hi-res models backing off a
bit. With that said, the ingredients are supportive with low
values of SBCAPE and decent low-level saturation, so definitely
something to monitor closely.

Another potential impact late tonight through early Wednesday
AM is for blowing and drifting snow in open and rural areas,
which would be favored north of I-80 in Iowa where there is a
deeper snowpack and temperatures will not be above freezing as
long as other locations to the east/south. There is uncertainty
with how impactful the blowing snow will be due to melting today
into tonight ahead of the cold front. But with such strong
winds expected, thought it was prudent to extend the Winter
Weather Advisory through mid morning on Wednesday to account for
the potential visibility reductions from either some falling
snow and/or blowing snow. A Wind Advisory is in effect south of
Highway 30, but even in this area there may be a period of
reduced visibilities from falling and/or blowing snow early
Wednesday morning which could impact the morning commute. Patchy
light snow and flurries may linger through Wednesday afternoon
as winds decrease significantly with temps holding in the 20s
and 30s.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Issued at 230 PM CST Tue Dec 9 2025

The pattern looks to remain active with a couple of clipper systems
progged to cross the region, primarily for the Thursday night and
Saturday time frames. Additionally, a very cold weekend is likely,
with Saturday night/Sunday morning potentially bitterly cold.

First, let`s discuss the clippers. The first is progged to come
through Thursday night, driven by 850-700 mb layer warm air
advection/frontogenetic forcing. Precipitation types appear to be
largely snow in our CWA, although there is a noticeable warm nose
aloft around the 700-800 mb layer in the NAM/GFS soundings over our
southern counties, which could support a wintry mix. Where snow is
expected, this clipper could bring a few inches of new snow
accumulation, given NBM probabilities of two inches of snow or
greater is around 40-60%, particularly over northwestern Illinois
into northeastern Iowa. The character of the snow appears to be more
of a slightly drier snow to the northeast (snow ratios of 13-15:1)
compared to farther southwest, where a wetter snow is more likely
(snow ratios 7-10:1). Precipitation should be mostly over by sunrise
Friday morning, with high pressure gradually nosing into the region
through the day. A much colder air mass is expected to move into the
region Friday night, right before the second clipper moves across
the area Saturday. Friday night low temperatures look to fall to the
single digits above zero for most locations. Due to the colder air
mass in place, p-types are expected to be entirely snow, and pretty
dry and fluffy snow at that. LREF ensemble mean soundings shows a
deep thermal profile (from the surface up to around 700 to 600 mb)
firmly within the DGZ, which supports a dry, fluffy snow character.
Snow ratios of 15-19:1 are very much on the table, but with a weak
signal for snow, it appears that blowing snow isn`t going to be much
of an issue. The second clipper appears to have a weaker signal for
snow accumulations compared to the first, with NBM probs of two
inches only around 30-50%.

In the wake of the second clipper system, an arctic air mass builds
in for Saturday night into Sunday morning. Both the GEFS and ECMWF
ensembles for 850 mb temperatures suggest magnitudes around 12 to 16
degrees C below zero, which would be some of the coldest air yet
this season. These 850 temperatures would be near the daily minimum
for December 14th at 12z (6 AM) per SPC sounding climatology, so a
very cold air mass for this time of the year. Northwest winds look
to stay elevated enough to combine with negative single digit and
lower teens low temperatures to support widespread wind chill values
of -15 to -30 degrees for most of the CWA Sunday morning. LREF
exceedance probabilities of wind chills 20 degrees below zero or
colder is around 50-80% for locations along and north of Interstate
80, so a pretty strong signal for a bitterly cold morning. Cold
weather headlines are likely needed, if these trends continue. After
Sunday, temperatures look to gradually warm as southerly return flow
around the departing high should moderate temperatures into the
early portions of next week.

&&

.AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/...
Issued at 1158 AM CST Tue Dec 9 2025

Active weather expected in this TAF period with strong winds,
LLWS, periods of light precipitation and low clouds. Light
freezing rain is possible this evening, mainly at DBQ with
temperatures initially around freezing before warming into
tonight. A strong area of low pressure will pass to the north
across Wisconsin tonight and bring a cold front through the
area, leading to very strong WNW to NW winds up to 35 - 45 kts
into Wednesday AM. The gusty winds will likely be accompanied by
a period of either snow showers or a steadier light snow,
resulting in visibility reductions to MVFR/IFR; expect
prevailing MVFR ceilings at all the terminals later tonight into
Wednesday AM, and IFR possible at DBQ. Additionally, blowing
snow could become a concern at CID with low confidence on the
impact to visibility at this time.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory from 6 PM this evening to 9 AM CST
     Wednesday for IAZ040>042-051>054.
     Wind Advisory from midnight tonight to 9 AM CST Wednesday for
     IAZ063>068-076>078-087>089-098-099.
IL...Winter Weather Advisory from 6 PM this evening to 9 AM CST
     Wednesday for ILZ001-002-007.
     Wind Advisory from midnight tonight to 9 AM CST Wednesday for
     ILZ009-015>018-024>026-034-035.
MO...Wind Advisory from midnight tonight to 9 AM CST Wednesday for
     MOZ009-010.

&&

$$

SHORT TERM...Uttech
LONG TERM...Schultz
AVIATION...Uttech