Osco, Illinois Weather Forecast Discussion

022
FXUS63 KDVN 241028
AFDDVN
Area Forecast Discussion
National Weather Service Quad Cities IA IL
528 AM CDT Wed Sep 24 2025
.KEY MESSAGES...
- Dry conditions today after sunrise, with near seasonable
  temperatures.
- Prolonged period of dry conditions and above normal
  temperatures expected Thursday through early next week, with
  comfortable humidity.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 240 AM CDT Wed Sep 24 2025
Surface analysis and morning radar mosaics show a weak surface low
near KPIA with a few light showers/sprinkles in northeast MO into
north central IL. GOES 19 water vapor imagery shows a compact upper
low rotating over western KS and another wave dropping south out of
central WI. Temperatures at 2am, ranged from 59 degrees in
Independence and Monticello, to 67 degrees in Burlington.
Today...the aforementioned upper low over KS to slide east across
MO, with better lift and moisture remaining to our southeast. As a
result, have removed any PoP mention for the daylight hours and
now have a dry forecast area-wide. Weak CAA as shown by 850mb
temps dropping into the 9-11C range and decreasing high clouds
will be seen through the day, yielding afternoon highs in the
middle 70s. In addition, forecast soundings show mixing up to
800mb that should keep dewpoints a little lower today.
Tonight...clearing skies and BL decoupling will allow temps to drop
into the lower 50s. Some patchy fog may also develop, primarily in
low lying areas and river valleys.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Issued at 240 AM CDT Wed Sep 24 2025
Thursday-Saturday Night...northwest flow aloft to start the
period transitioning to an omega block this weekend, will bring
a prolonged period of dry conditions, comfortable humidity, and
above normal temperatures. A cold front will move through
Saturday night, but 1000-500mb RH progs continue to show quite a
bit of dry air to overcome and I have continued a dry forecast.
Highs in the upper 70s and lower 80s are expected and while
this is still above normal for late September, the humidity
levels will be lower making for great conditions for any outdoor
plans.
Early Next Week...all 12z deterministic and ensemble model
solutions continue to show a building upper ridge bringing
warmer and continued dry conditions. Ensemble 850mb temps to
rise into the 15-16C range Sunday through Tuesday, which is
near or above the 90th percentile per SPC climatology. Taking a
look at the NBM members distribution for highs at MLI for the
28th through the 30th, now shows over 2/3rds of the members with
a high over 80 degrees each day. Not surprisingly, the NBM
loaded highs were 2-3 degrees higher for Sunday-Tuesday, with
some upper 80s possible on Monday. There is also high confidence
in dry conditions for the rest of September, with all but 3 of
the 100 members of the NBM showing no precipitation. This will
be good to dry out the fields, but not so much to alleviate any
developing drought conditions.
&&
.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 525 AM CDT Wed Sep 24 2025
MVFR stratus deck that formed early this AM near BRL to improve
to VFR by 13z. Otherwise, some MVFR/IFR fog and low clouds
moving southwest out of WI may impact the DBQ terminal this
morning before mixing out. Northeasterly winds increase this
afternoon, but should remain under 15 kts. Clearing skies and
calm wind late in the period may bring more fog potential, but
left out of TAF at this time.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Gross
LONG TERM...Gross
AVIATION...Gross

NWS DVN Office Area Forecast Discussion