Freeport, Illinois Weather Forecast Discussion

149
FXUS63 KDVN 120838
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
338 AM CDT Fri Sep 12 2025
.KEY MESSAGES...
- Hot weather is expected into early next week with highs in the
  upper 80s to mid 90s for much of the area.
- There are occasional chances for isolated showers and storms,
  but most of the area is expected to stay dry into early next
  week.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 315 AM CDT Fri Sep 12 2025
Today:
The main story will be the very warm temperatures for mid
September with highs in the mid 80s to lower 90s. An upper level
ridge is forecast to shift over the Mid to Upper Mississippi
Valley region from the west. SSE to S flow in the low-levels
will result in increasing warm air and moisture advection into
eastern Iowa and northwest Illinois, leading to an uptick in
humidity with dewpoints reaching the lower 60s. Persistent
isentropic lift aloft, along with convergence near the nose of a
SSW low- level jet, may result in isolated shower development
from the late evening into tonight north of Highway 30. Model
QPF is minimal though with amounts of only a trace to a few
hundredths; have included lower end chances (10-20%) in the
forecast for this period.
This Weekend:
Anomalously warm 850mb temperatures in the lower 20s (C) and
plenty of sun will lead to impressive mid September heat this
weekend with highs in the low to mid 90s for most locations. In
coordination with surrounding offices, dropped forecast highs a
few degrees below the NBM due to low confidence on the
widespread upper 90s it was showing. Increasing humidity levels
with dewpoints as high as the mid/upper 60s will create peak
heat indices in the mid 90s to near 100 degrees. A steady
southerly wind on Saturday may provide "a little" relief from
the heat when compared to Sunday when light and variable winds
are expected. [See the Climate Section for daily records which
are approximately 3-5 degrees warmer than the current forecast
highs]
Scattered showers and possibly a few isolated storms could skim
portions of NW Illinois mainly Saturday morning with elevated
instability over the region. The more focused area of showers
and storms is anticipated to be across far southern Wisconsin
into north-central and northeast Illinois, along a Lake Michigan
enhanced surface boundary. Aside from the Saturday AM chances
for scattered showers and isolated storms across the northeast
portion of the outlook area, the majority of the weekend should
be dry with warm 850-700mb temperatures and the absence of a
focused trigger both acting to inhibit organized convective
development. With that said, an isolated shower or storm could
develop during peak daytime heating.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
Issued at 315 AM CDT Fri Sep 12 2025
With a trough now likely to stay mainly to our west, the ridge
is also likely to remain in more firm control of our area
extending into early next week. Thus the hot weather continues,
though perhaps a couple of degrees cooler than this weekend.
Long range guidance varies considerably when it comes to
multiple troughs to our west and the resulting impact on the
ridge during the middle to later part of next week. As a result,
we`re not very confident on how long the heat will last and
when our next significant rain chances will be. When the ridge
finally releases its grip and a trough moves in will be our best
shot at more widespread rainfall and a shift toward cooler
temperatures. At this point that doesn`t look likely until
Wednesday at the earliest, but potentially not until the end of
next week.
&&
.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1245 AM CDT Fri Sep 12 2025
VFR expected to prevail through the period as high pressure over
the Great Lakes begins to gradually shift to the east. Expect
light winds around 10 kts, but a bit stronger at CID gusting
15-20 kts on Friday. There is a slight chance for a few isolated
showers or occasional sprinkles late in the period near CID and
DBQ; left out mention in the TAFs due to low confidence on
coverage.
&&
.CLIMATE...
Issued at 315 AM CDT Fri Sep 12 2025
Record High Temperatures:
September 13:
KBRL: 98/1927
KCID: 96/1930
KMLI: 97/1939
KDBQ: 96/1939
September 14:
KBRL: 99/1939
KCID: 96/1939
KMLI: 99/1939
KDBQ: 97/1939
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Uttech
LONG TERM...Kimble/Uttech
AVIATION...Uttech
CLIMATE...Uttech

NWS DVN Office Area Forecast Discussion