639
FXUS63 KDVN 072319
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
519 PM CST Sun Dec 7 2025

.KEY MESSAGES...

- A weak upper level disturbance will bring flurries and
  possibly patchy light snow late tonight into Monday morning.

- An active weather pattern will be seen this week with several
  systems passing near or over the area. Each system has the
  potential to bring some precipitation to the area.

- Another surge of arctic cold will settle into the Midwest for
  the end of the week and weekend. This arctic cold is be
  monitored for any potential cold headlines.

&&

.SHORT TERM /THROUGH MONDAY/...
Issued at 224 PM CST Sun Dec 7 2025

Clouds will be on the increase late this afternoon and overnight as
return flow aloft develops. The combination of weak lift and
returning moisture will allow saturation aloft to occur resulting in
flurries developing. The flurries will overspread the area after
midnight and exit the area Monday morning.

Clouds will begin breaking up late Monday morning but a partly to
mostly cloudy sky is expected ahead of the next system.&&

.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
Issued at 224 PM CST Sun Dec 7 2025

Monday night/Tuesday
Assessment...high to very high (80-90%) confidence of a clipper
system side-swiping parts of the area

The first of many systems races from the northern Plains and into
the Great Lakes Monday night into Tuesday morning. Based on the
track being well north of the area, the better forcing and moisture
will move from Minnesota into Wisconsin. The forecasted water
equivalent remain under 0.02 inches. Thus flurries or possibly a
brief period of light snow is possible east of a Dubuque, IA to
Princeton, IL line. If the light snow scenario is realized,
accumulations would only be a dusting.

Breaks developing in the clouds combined with southerly flow will
help boost temperatures above normal for Tuesday.

Tuesday night/Wednesday
Assessment...high to very high (80-90%) confidence of a second
clipper system impacting the area

Right on the heels of the first clipper system, another clipper
system will move through the upper Midwest and into the Great Lakes
Tuesday night into Wednesday.

Like the previous system, the track is north of the area but further
south. Unlike the first system, all models have this system stronger
(985-990 mb center). Thus with this system being a tad further
south, it will transport moisture into the area allowing light
precipitation to occur across the area.

With the initial warmer temperatures across the area, the
precipitation will start out as rain with a potential rain/snow mix
developing late Tuesday night in the Highway 20 corridor before
ending Wednesday morning.

Given the differences in the track of this system, the model
consensus has expanded the coverage of precipitation to most of the
area. Precipitation chances range from 15-50 percent south of an
Manchester, IA to Galva, IL line. North and east of this line
precipitation chances are 55 to 75 percent.

The strength of this storm system means that windy conditions will
develop late Tuesday night into Wednesday with gusts up to 35 mph
possible.

Wednesday night through Thursday night
Assessment...medium (40-60%) confidence on light accumulating snow
occurring

All global models show a weak upper level disturbance moving through
the area late Wednesday night into Thursday. The Boehmke rule is
satisfied, thus the precipitation will be in the form of snow.

In looking at the NBM 10-90th percentiles, the maximum water
equivalent would be around 0.10 inches with a higher probability of
it being less. With overnight temperatures expected to be in the
teens, the snow has a higher probability of being the dry, fluffy
type (i.e. rain/snow ratios greater than 12 to 1). In using the mean
water equivalent of 0.03 inches, such a ratio would translate into
just under an inch of accumulation for the likely max amount. Most
areas would thus see a dusting of accumulation.

There are timing differences between the models which translates
into on 30-50 percent chances for snow. I fully expect the snow
chances to slowly increase as the week progresses.

The bulk of the snow looks to be during the day Thursday with snow
beginning late Wednesday night and ending Thursday evening.

Friday through Sunday
Assessment...a certainty (>99% confidence) of another arctic surge
into the Midwest

The global models show another arctic surge into the Midwest for the
end of the week and into the weekend. The trigger will be the
passage of an arctic cold front either very late Thursday night or
during the day on Friday.

The strength of the arctic surge associated with the front raises a
strong potential for flurries or snow showers along with wind gusts
of at least 30 mph. Right now the model consensus has Friday dry but
I suspect this will change as the week progresses.

After the arctic front passes, well below normal temperatures will
be seen Friday night through Sunday. The wind will be slow to
diminish Friday night. The situation needs to be watched but the
potential is there for cold headlines Friday night into Saturday and
again Saturday night into Sunday. Of the two nights, the probability
of a cold headline is higher for Friday night than it is for
Saturday night.

The Friday night through Sunday time frame will be mainly dry.
However, there is a weak upper level disturbance that will move
through the area Saturday night that could produce light snow or
flurries. This far out the signal is quite weak but the model
consensus is generating 15 percent chances for light snow.

&&

.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 516 PM CST Sun Dec 7 2025

A cold, quiet, VFR night is expected tonight, with a gradual
increase in mid and high clouds later this evening, continuing
through Monday. While there could be a flake or two of snow,
this should have no impact to aviation and the main impact
tonight will be the cold weather itself as we`ll be several
degrees below zero at most sites tonight.

Winds will shift around towards the south/southeast Monday
morning, and increase to around 10 kts by afternoon.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.

&&

$$

SHORT TERM...08
LONG TERM...08
AVIATION...Ervin