849
FXUS63 KDVN 201137
AFDDVN

Area Forecast Discussion
National Weather Service Quad Cities IA IL
537 AM CST Thu Nov 20 2025

.KEY MESSAGES...

- Dense fog is expected into the morning commute, especially in
  parts of eastern Iowa.

- Precipitation chances return to parts of the area on Friday,
  but confidence remains low. If we do see precipitation, it
  should remain light and largely in our south.

- A quiet weekend under northwest flow will lead us into a
  potentially wet start to the new work week. Active and cooler
  weather to follow later next week.

&&

.UPDATE...
Issued at 533 AM CST Thu Nov 20 2025

Visibilities have very slowly fallen overnight in most areas,
but along an axis from near Ottumwa, through Cedar Rapids to
Dubuque, we`ve seen persistent 1/4 mile visibilities develop.
These have taken a long time to drop, but with low cloud heights
near ground level, it`s apparent that these low conditions are
likely to impact the morning commute in that narrow axis. A
dense fog advisory has been issued there, through 10 AM.

&&

.SHORT TERM /THROUGH FRIDAY/...
Issued at 226 AM CST Thu Nov 20 2025

Another dreary forecast for us today, as we will once again be
socked in low stratus through much, if not all, of the day. We will
also start the day with patchy dense fog, with latest obs largely
keeping this north of the Highway 30 corridor. With the low clouds
remaining overhead today, temperatures will once again be several
degrees cooler than initially advertised. Based on the last two
days, the diurnal range was generally 5-8 degrees. Thus, we can
expect similar, with upper 40s in our north to low-mid 50s in our
south. Light winds will also remain through the day, with
drizzle/mist remaining possible for areas north of Highway 30.
Otherwise, we should largely remain dry and calm through today.
Tonight, we get a reinforcing shot of moisture as southwest
flow kicks in ahead of the next approaching wave. Thus, we will
continue to see a full sky of clouds, helping to moderate
temperatures again. Tonight`s lows will be in the mid-upper 30s
in our north, with mid 40s possible in our south.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Issued at 226 AM CST Thu Nov 20 2025

The long awaited wave ejects off of the Rockies on Friday, trekking
east-northeast and being shunted south of our area by the northern
jet stream. This will keep much of the energy south of our forecast
area, with some bouts of energy reaching our south through the
day on Friday. Thus, we will see rain chances increase through
the day, with best chances to see any rainfall along/south of
Highway 34. At this point, this is depicted well through much of
guidance. Areas north of the Highway 34 corridor will largely
remain dry, but a light shower/drizzle cannot be ruled out as we
head north to Interstate 80. Overall, accumulations will be
low, with those that see rain largely seeing <0.25". Otherwise,
Friday will be another overcast/gloomy day for the forecast
area. Although, temperatures may be a little warmer than the
previous days, hovering in the low 50s.

This weekend, our weather will largely be influenced by weak upper
level northwesterly flow. We will see some llvl southwesterly flow
through the weekend as well, as weak perturbations pass through the
flow. Rather than seeing precipitation from these, this will largely
impact temperatures and winds. Current forecast favors above normal
temperatures, with low-mid 50s possible on Saturday, trending milder
on Sunday as we see weak ridging over the area. These have once
again trended upwards since the last forecast package. With us
sitting under northwest flow and then a ridge building over the
Midwest late in the weekend, we are looking at quiet and dry
weather. The best part of this weekend`s forecast is that we should
finally see some sun, after days under a blanket of low stratus.
Thus, if we can get the above normal temperatures and sun, we are in
for quite a beautiful weekend. Confidence is moderate-high in this.

Since the last forecast package, much of guidance has trended wetter
for the start of the next work week. So, we are looking at a wave
developing/deepening over the Rockies on Sunday, with a deepening
trof over the Pacific Northwest (behind it). This trof will continue
to dig southeast into the Rockies, allowing the wave ahead of it to
track northeast into the Upper Mississippi River Valley. This is
quite the change since 24 hours ago, as the leading wave was progged
to trek south of the area. Now that we may see this wave move right
through us, precipitation chances are back on the table for the
Monday/Tuesday timeframe. Granted, this is a new trend and will
likely see some change as we get closer to that timeframe. In either
case, all global models and some ensemble suites have trended
towards this wetter route, bringing widespread light-moderate rain
to the area. Thus, an umbrella might be necessary at the start of
the work week. After this system passes through, it looks to remain
active, as well as trending cooler. This is supported by the
extended forecasts provided by CPC as well.

&&

.AVIATION /12Z TAFS THROUGH 12Z FRIDAY/...
Issued at 510 AM CST Thu Nov 20 2025

Low IFR conditions are found over much of eastern Iowa and
northern Illinois, mainly with low CIGs around 200-500ft, and
visibility between 1/4 mile and 2 miles in dense fog, and some
light drizzle. Somewhat better, but still IFR conditions are
found farther south at MLI and BRL. These low conditions will
slowly improve this morning, but remain at least MVFR through
early afternoon. Tonight, models indicate improving conditions,
but I`ve gone with persistent MVFR cigs at all locations
tonight, as until this pattern breaks down, lower conditions are
expected during the overnight hours.

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Dense Fog Advisory until 10 AM CST this morning for IAZ042-
     052>054-063>065-076-077.
IL...Dense Fog Advisory until 10 AM CST this morning for ILZ001.
MO...None.

&&

$$

UPDATE...Ervin
SHORT TERM...Gunkel
LONG TERM...Gunkel
AVIATION...Ervin