430
FXUS63 KDVN 210441
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
1041 PM CST Mon Jan 20 2025

...Updated for 06z Aviation...

.KEY MESSAGES...

- Cold Weather Advisories are in effect for this evening through
  Tuesday morning, including an Extreme Cold Warning along and
  north of Highway 30.

- Light accumulating snow is expected very late Tuesday night
  through Wednesday evening. Accumulations look to be an inch or
  less.

- Mainly dry conditions the remainder of the week and through
  next weekend with moderating temperatures.

&&

.UPDATE...
Issued at 941 PM CST Mon Jan 20 2025

Have expanded the Extreme Cold Warning to portions of the I-80
corridor based on update lows and winds anticipated to be slower
to diminish tonight.

&&

.SHORT TERM /THROUGH TUESDAY/...
Issued at 147 PM CST Mon Jan 20 2025

The cold weather headlines have been extended until noon Tuesday.

A weak upper level disturbance will bring some isolated flurries or
ice crystals to the area through midnight. After midnight the winds
will slowly diminish as the arctic high builds into the area.

The main question is how quickly will the clouds clear behind the
departing upper level disturbance. It appears that this will occur
very late tonight to around sunrise Tuesday right as winds diminish
to 5 to 10 mph. If correct, temperatures and related wind chills
would experience a quick drop around sunrise.

Improvements to the dangerous wind chills will slowly occur between
9 AM and 12 PM on Tuesday. With the upper level thermal trof moving
through on Tuesday, much of the area looks to remain in the single
digits.

Tuesday afternoon winds will increase as the high moves into the
Great Lakes keeping wind chills low but generally below zero.

&&

.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Issued at 147 PM CST Mon Jan 20 2025

Tuesday night through Wednesday night
Assessment...medium to high confidence for light snow

A weak clipper type system will move through the upper Midwest late
Tuesday night through Wednesday evening. While the better forcing
runs from Minnesota into Wisconsin, the moisture moving in over the
retreating arctic air will be enough to produce fluffy light snow
with some accumulation.

Right now the main time frame for the light snow looks to be during
the day Wednesday with possibly some light snow occurring on either
side of that time frame. Right now there is a 30-40 percent chance
of accumulating light snow for Wednesday. These chances will likely
increase over the next 24 hours.

Thursday through Monday
Assessment...high confidence on moderating temperatures. Medium
confidence on dry conditions.

The model consensus has dry conditions from Thursday through Monday
with moderating temperatures. While there is high (>80 percent)
confidence of moderating temperatures, the confidence is medium (40-
50 percent) on dry conditions.

Northwest flow aloft will continue across the area through next
weekend. However, most model solutions have a weak upper level
disturbance moving through the area Friday night into Saturday.
While moisture is very limited, I would not be surprised if flurries
or some spotty light snow occurs.

There is also a second weak upper level disturbance progged to move
through the area. Unfortunately, the models disagree on the timing
of this disturbance. Some suggest as early as Sunday while others
delay the arrival until Monday. Thus there may be the potential
(albeit low at 042-
     051>054-066.
     Cold Weather Advisory until midnight CST tonight for
     IAZ063>065-067-068.
     Extreme Cold Warning until noon CST Tuesday for IAZ063>065-067-
     068.
     Cold Weather Advisory until noon CST Tuesday for IAZ076>078-
     087>089-098-099.
IL...Extreme Cold Warning until noon CST Tuesday for ILZ001-002-007.
     Cold Weather Advisory until midnight CST tonight for ILZ009-
     015.
     Extreme Cold Warning until noon CST Tuesday for ILZ009-015.
     Cold Weather Advisory until noon CST Tuesday for ILZ016>018-
     024>026-034-035.
MO...Cold Weather Advisory until noon CST Tuesday for MOZ009-010.

&&

$$

UPDATE...McClure
SHORT TERM...08
LONG TERM...08
AVIATION...McClure

NWS DVN Office Area Forecast Discussion