644
FXUS63 KDVN 152327
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
527 PM CST Mon Dec 15 2025

...00z Aviation Update...

.KEY MESSAGES...

- The long-awaited warmup starts today, with temperatures 20-30
  degrees warmer than the weekend, trending even warmer over
  the coming days.

- Tonight, increasing moisture and light winds will foster a fog
  potential throughout the area.

- We will largely remain dry through the long term period, aside
  from the chance for light rain on Thursday with a passing
  system.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 135 PM CST Mon Dec 15 2025

High pressure off to our east and a weak wave approaching from the
northwest have induced modest southwesterly flow throughout the
area. This has resulted in quite the increase in temperatures when
compared to those over the weekend. Widespread temperatures in the
mid-upper 20s, with even some 30s in our south, have been observed.
Along with warmer temperatures, we have also increased moisture
through the area and seen some light melting in areas. As we go into
the nighttime hours, we will see temperatures drop back into the
teens quickly, owing to radiational cooling. With light winds
overnight and clear skies, this cooling will promote a fog
potential for at least areas along/north of Interstate 80. This
is supported with short term ensemble systems, indicating a
40-60% chance for visibilities less than a half mile. Although,
there is some concern that the fog will extend south of the
interstate, given a warm front passing near the area tonight
with the next approaching wave. This would provide a focused
area of moisture over the area of snowmelt, along a with a weak
convergence point. Thus, will mention at least the chance for
patchy fog south of the interstate. With temperatures below
freezing, freezing fog will be possible as well.

Tomorrow, the aforementioned wave will pass through the area.
Moisture will remain limited near the surface, keeping this a dry
passage. Rather, we can expect a seasonal breeze and passing clouds
through the day. Ahead of the wave, we will see another surge of
southwesterly flow, which will bring along another day of milder
temperatures. Temperatures will be in the 30s throughout, with
temperatures near or slightly above 40 moving in to some of our
southern counties.

&&

.LONG TERM /TUESDAY THROUGH MONDAY/...
Issued at 135 PM CST Mon Dec 15 2025

We are in for quite the pattern change for the remainder of the work
week. Upper level flow will generally be zonal going into Wednesday,
becoming more amplified through the second half of the week. LLVL
flow will continue to be southwesterly, ushering warm advection into
the region. Thus, temperatures are forecast to be above average,
with upper 30s and low 40s forecast for most Wednesday and Thursday.
We will continue to see a mix of clouds/sun through midweek as well,
with systems passing to our north. Although, we will remain dry
locally due to lacking moisture return and better forcing well north
of the area. With this warmup going on, we should expect to see the
snowpack decrease through much of the area. Observations indicate
that there is about 0.50-1.00" of liquid water in the snowpack,
which means we are in for a muddy second half of the week.

The second half of the week, we will start to see the zonal flow
pattern becoming more amplified, as stronger waves push into the
Upper Midwest. We continue to watch a wave that is forecast to come
through Wednesday night into Thursday, as it will bring through our
next bout of precipitation. Unlike we have seen for a bit, the
primary precipitation expected with this system is rain. This will
be a seasonally strong wave that passes through, with strong
forcing. Best forcing will be closer to the surface low, well north
of the area though. Strong southwesterly flow ahead of this wave
will cause temperatures to increase into the low-mid 40s, with a
strong pressure gradient over the area bringing breezy conditions.
As was mentioned in the previous forecast package, there will be the
chance for gusts between 30-40 mph Thursday. As was mentioned above,
temperature profiles would favor the primary precipitation type as
rain. Some guidance even hints at some instability working in. So, a
rumble of thunder or two cannot be ruled out either, largely in our
south. This will be a quick-hitting system, which will limit overall
precipitation amounts. WPC guidance continues to show <0.25".

Behind this system, very cold air will once again filter into the
area behind the cold front Thursday night, bringing temperatures as
low as the teens to single digits. Thus, there will be a chance for
light snow to mix in on the back end of the system. Although,
impacts from that are not expected at this time. This bout of cold
air will be short lived, with temps back near 30 on Friday. From
there, the upper level pattern will still feature weak perturbations
working through the area in near-zonal flow. Precipitation chances
seem low at this point, owing to lack of moisture return. With these
passing waves, temperatures will also be up and down through the
weekend. Although, temperatures seem to remain near or above normal.
Thus, a welcome change in temperatures for the long term period,
aside from the brief cold Thursday night.

&&

.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 525 PM CST Mon Dec 15 2025

The watch for fog development will be on for the overnight
especially along and north of I-80. Light and variable sfc winds
or light southerly flow, will combine with mainly clear skies
with just some cirrus streaks and snowmelt to produce the chance
of fog development as the night progresses. A slight sfc wind
convergent zone may make the fog more favorable along and north
of I-80 and west of the MS RVR in portions of east central and
northeast IA. IFR to LIFR conditions may be possible especially
at CID and DBQ, but it may be close to MLI as well. Increasing
south to southwesterly sfc winds on Tuesday will help improve
the conditions by late morning, but will have to watch for the
fog to lift into a low MVFR deck for a few hours until the
afternoon.

&&

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

&&

$$

SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...12