Yates, Illinois Weather Forecast Discussion

415
FXUS63 KILX 221950
AFDILX
Area Forecast Discussion
National Weather Service Lincoln IL
250 PM CDT Mon Sep 22 2025
.KEY MESSAGES...
- The unsettled pattern will continue with daily rain chances
  through at least Thursday. The best chance of rain is Tuesday
  night and Wednesday (60-80% southeast of the IL river). New
  rainfall amounts of over 2" are possible, with the best chance
  being southeast of I-70 (30-45%).
- Fog development, some of which could be dense, is likely
  overnight into the Tuesday morning commute. The best chance for
  visibility below a half mile is from I-55 southeast (50-70%).
&&
.DISCUSSION...
Issued at 245 PM CDT Mon Sep 22 2025
Radar mosaic shows the main area of showers and isolated
thunderstorms had passed east and south of IL with scattered
convection in far southeast/southern IL, se of a Bloomington IN
to Marion IL line. A few isolated light showers were east of I-55,
otherwise much of CWA is now dry. Some sunshine was appearing
through the low/mid clouds nw of a Taylorville to Decatur to
Champaign while nearly overcast MVFR clouds 1-2k ft lingered in
southeast IL.
Isolated showers possible into early evening in eastern IL and
late tonight north of a Galesburg to Lacon line as convection
chances increase over northern IL during tonight. Latest CAMs show
fog developing in southeast IL early overnight and spreading
northward into central IL during the overnight and lingering into
mid Tue morning. RAP and HRRR show more widespread fog by late
tonight from I-72 south and HREF has 50-70% chance of vsbys below
1/2 mile in this area, so dense fog is looking more likely over
southern half of cWA. May eventually need a dense fog advisory
from I-72 south. Also seeing patchy fog developing up the IL
river valley late tonight/early Tue morning, though mid and high
clouds increasing over northern/nw CWA toward dawn may limit
extent of fog. Lows overnight in the lower 60s, with mid 60s se of
I-70.
A developing upper level low near the CO/KS border late Tue to
have some short waves ejecting eastward into central IL late Tue
afternoon and Tue night and will see increasing chances of
convection over area later Tue into Tue night. Also an outflow
boundary from convection in southern WI to move into northern CWA
and could develop its own convection during Tue afternoon and a
few cells could become strong. SPC day2 outlook does not have a
marginal risk of severe storms over central/se IL though will need
to monitor northern CWA for Tue afternoon into early Tue evening.
Warmer highs Tue in the lower 80s and still muggy with dewpoints
in the upper 60s.
The cutoff low and trof to move into MO by late Wed and bringing
our best chances of more widespread showers and a few
thunderstorms Tue night and Wed with pops of 60-80% se of the IL
river. The heaviest rains appears to set up over southern cWA Wed
into Thu evening when 1-2 more inches of rain possible. Areas
south of I-70 have a 30-45% chance of seeing over 2 inches of
rain. As been the case the past few days, a few spots could see
locally 3-5 inches over southern CWA but this will be more
isolated if it occurs. WPC has much of central and se CWA in
marginal risk of excessive rainfall Wed and Wed night (and over
southern CWA Tue night). Cooler highs in the mid 70s Wed and mid
to upper 70s Thu. Surface low appears to pass south of CWA WEd and
Wed night near or just north of the Ohio river while upper level
trof axis moves east of IL during Thu afternoon. Have chances of
showers Thu with highest pops 30-40% in eastern IL and qpf
amounts to be lighter.
Models have trended quickly with moving upper level trof east of
IL late this work week and much of area appears drier Thu night
and Fri as upper level ridge building into the central Rockies and
Central Plains. We kept slight chance of showers in eastern IL
Thu evening. Cutoff low still forecast to be over the gulf coast
and southeast Atlantic States this weekend with upper level
ridging into IL, keeping us dry and warmer. Highs in the low to
mid 80s Saturday through Monday.
The Climate Prediction Center (CPC) 8-14 Day Outlook for Sep 30
through Oct 6 has 55-60% chance of above normal temperatures over
central and southeast IL. Precipitation trending near normal or
slightly below normal over far ne and east central IL.
07
&&
.AVIATION...  (For the 18z TAFs through 18z Tuesday Afternoon)
Issued at 104 PM CDT Mon Sep 22 2025
Despite the departure of the rain several hours ago, MVFR
ceilings are lingering over all our terminals except PIA. Heating
of the day should lift the cloud deck and mix out some of the
lower ceilings, leaving VFR conditions for the rest of the day and
this evening. Then attention turns to increasing potential of
dense fog and LIFR ceilings later tonight and Tues morning
(09z-13z). Introduced 1/2sm FG where the potential is higher for
dense fog, which would be our eastern terminals of BMI/DEC/CMI,
but we can`t rule out SPI getting dense fog as well. There may
need to be even lower vis to 1/4 mile for CMI/DEC/BMI with
upcoming TAF issuances going forward.
Shimon
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS ILX Office Area Forecast Discussion