Sheldons Grove, Illinois Weather Forecast Discussion

388
FXUS63 KILX 201954
AFDILX
Area Forecast Discussion
National Weather Service Lincoln IL
254 PM CDT Sat Sep 20 2025
.KEY MESSAGES...
- Unsettled conditions are forecast to prevail across central and
  southeast IL through Friday, with frequent chances for scattered
  showers and thunderstorms.
- A few storms could be strong to severe Sunday afternoon east of
  I-57. Strong wind gusts are the main concern.
- Over the next week through 7 pm Friday, the best chance for
  total rainfall amounts to exceed 2" is in areas south of
  I-72/Danville (50-70% chance).
&&
.DISCUSSION...
Issued at 245 PM CDT Sat Sep 20 2025
A negative tilted upper level trof had 571 decameter 500 mb low
along the ND, Saskatchewan and Manitoba line and a 574 decameter
500 mb low along the far se MN corner near WI/IA border. The trof
extended over Iowa, northeast MO and central/nw IL. Surface map
shows a weak boundary between the IL river and I-55 with clusters
of convection tied to this boundary east of Jacksonville around
Springfield and over Woodford and eastern Marshall counties. A few
more clusters of convection was from Effingham sw to St Louis
area. More convection in ne MO, se Iowa and into west central IL.
MLCAPEs were 1000-1700 j/kg east of the IL river and 0-6 km bulk
shear values of 20-30 kts, highest over west central IL. PW
values had come up to 1.4-1.75 inches from IL river east with
highest values from Lincoln SSW into east central MO. Atlanta IL
had 1 inch hail around 115 pm. Temperatures had heated up into
the mid to upper 80s from Decatur and Champaign se with Mt Carmel
airport at 90F. Temps in the 70s from I-55 nw and areas that
recently received rainfall had cooled into the upper 60s and lower
70s. Dewpoints ranged from 55-65F with highest dewpoints along
I-55.
The HRRR model appears to be handling convection the best so far
today and leaned on in for near term forecast. Diurnally enhanced
convection could linger longer into this evening in areas from
I-70 nw with convection possible in southeast IL overnight into
Sunday. Better coverage of convection to redevelop and move in
from the sw later Sunday afternoon into Sunday night especially
from I-70 nw again as next short wave pivots into area from MO.
SPC has marginal risk of severe storms Sunday afternoon in far
eastern IL (IL counties bordering Indiana) for gusty winds, but
would not be surprised of hail occurs again like today. Isolated
pockets of 1.5-2.5 inches of rain possible too Sunday
afternoon/evening per LPMM from HREF model. Highs Sunday similar
to today as we are in similar air mass, with mid to upper 80s from
I-72 south and around 80 to lower 80s IL river valley. Getting
more humid as dewpoints rise into the mid to upper 60s.
More widespread convection that likely arrives during Sunday night
into Monday with short wave trof could bring more beneficial
rainfall, with half to 1 inch expected over much of central IL
from Sunday night into Mon evening, with over 1 inch possible
especially in southeast IL. Between quarter to half inch from
Peoria nw to Galesburg where amounts appear lighter. More
widespread cloud cover and showers on Monday to bring cooler highs
in the upper 70s and lower 80s. Still humid with dewpoints 65-70F.
A new upper level low developing over central high plains Tue to
track slowly eastward into the mid MS river valley Thu/Thu night
and into the Ohio river valley late this week. This will likely
bring several rounds of convection to the area through the week,
with heavier amounts Wed and Wed night and shifting more into
southeast IL with the higher pops/heavier qpf Thu-Fri. Areas from
I-72 south appear to have best chance of seeing 2-4 inches of
rainfall this coming week with locally higher amounts possible
especially se IL. WPC has marginal risk of excessive rainfall
Sunday through Wed night over central and southern parts of IL.
Cooler highs in the mid 70s Wed-Friday.
07
&&
.AVIATION...  (For the 18z TAFs through 18z Sunday Afternoon)
Issued at 1256 PM CDT Sat Sep 20 2025
Surface boundary just west of a KBMI-KSPI line is serving as a
focus for thunderstorm development early this afternoon. Most
thunder mention in the initial stages of the TAF`s are at these
two sites, with a PROB30 mention at other sites by mid afternoon.
After an initial wave of convection, another round is expected to
move northeast this evening, but not enough certainty to go more
than PROB30 at this stage. Some brief MVFR conditions are possible
with the heavier rains.
With boundaries in the area, there will be a fair amount of
variability in wind direction through the evening, before trending
more southerly late night into Sunday morning.
Geelhart
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS ILX Office Area Forecast Discussion