Springfield, Illinois Weather Forecast Discussion

993
FXUS63 KILX 220209
AFDILX
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
909 PM CDT Sun Sep 21 2025
.KEY MESSAGES...
- An unsettled pattern continues with periods of showers and
  storms throughout much of the work week. The highest rain
  chances are tonight into Monday night (60-80% chance southeast
  of the IL river tonight and early Mon, and in eastern/SE IL
  through Monday).
- There is a marginal risk (level 1 of 5) of severe storms through
  early evening from Canton to Bloomington south. Strong wind
  gusts are the main concern, although isolated hail up to the
  size of quarters could also occur.
- Through the end of the work week, the potential for heavy
  rainfall remains highest south of I-72/Danville where there is a
  40-70% chance for total rainfall amounts over 2 inches, and a
  20-30% for amounts over 3 inches from I-70 southeast.
&&
.UPDATE...
Issued at 908 PM CDT Sun Sep 21 2025
Only update needed is to pop/wx grids to better reflect reality
and expected forecast the rest of the night. Strongest storms have
now moved east of I-55 and only rain is left along the interstate
and to the west. Update will be out shortly.
Auten
&&
.DISCUSSION...
Issued at 245 PM CDT Sun Sep 21 2025
Isolated showers and thunderstorms have developed in past 1-2
hours from Logan county southward with a more concentrated area
of convection between SPI and DEC southward across Christian and
western Shelby counties. Isolated showers/thunderstorms had also
recently developed north of Peoria and Pontiac. Unstable air mass
in place once again with MLCAPES up to 1-2k j/kg and MUCAPES of
1200-2200 j/kg. Moist PW values of 1.4-1.6 inches, while 0-6 km
bulk shear values were low, 20-24 kts over central and SE IL.
Surface analysis a mid afternoon shows warm front lifting
northward into central parts of MN/WI. SSW to SW winds prevail
over central/se IL in warm sector with moist dewpoints in the 60s.
Temps had warmed into the 80s over much of CWA with upper 70s
from Galesburg to Lacon north. Aloft a 567 decameter low was over
NW and west central MN with its trof axis extending southward into
eastern parts of NE/KS and OK.
Short waves lifting ne from central/southern MO into central IL
during this evening will see more widespread development of
convection over CWA from sw to ne, with best chance of convection
from I-55 se tonight into Mon morning, and shifting more over
eastern/se IL Mon afternoon/evening. SPC has marginal risk of
severe storms for damaging winds possible from Canton to
Bloomington south into early evening. Small and even large hail
up to the size of quarters also a risk too. WPC has marginal risk
of excessive rainfall se of the IL river tonight and in southeast
IL tonight through Tue night. Have lower convection chances during
the day Tue with 30-40% over much of CWA (50% in far se CWA) as we
will be between short waves.
A new cutoff low forming over the central plains on Tue to track
into IL later Wed and Wed night, and bring more widespread showers
and a few thunderstorms to the area from Tue night through Thu.
WPC has marginal risk of excessive rainfall from I-72 south with
slight risk far se CWA for Wed and Wed night . The LREF shows
40-70% chance of over 2 inches of rain through early Friday from
I-72/Danville south with 20-30% chance over 3 inches from I-70
south. Areas nw of Peoria appear to be on the lower end of the
rainfall spectrum with half to 1 inch expected, though locally
higher amounts possible with thunderstorms. The LPMM shows
pockets of rainfall rates of 1-2 inches in less than 6 hours
mainly south of I-72 next few days. More clouds and showers around
on Monday to keep it cooler despite still being in warm sector
with SSW winds, with highs in the upper 70s. A bit warmer Tue in
the lower 80s with lower chances of convection. Highs mainly in
the mid to upper 70s Wed-Friday and upper 70s/lower 80s Sat/Sunday.
GFS and ECMWF show large upper level trof slowly shifting east of
IL late this week, though still close enough on Friday to bring
chances of showers especially eastern/se IL. Surface high pressure
ridge building into the western Great Lakes and upper Midwest next
weekend should return dryer weather to IL while upper level
low/trof appears to hang around the southeast states.
The Climate Prediction Center (CPC) 8-14 Day outlook for Sep
29-Oct 5th has a 50-60% chance of above normal temperatures over
central and southeast IL and 33-40% chance of below normal
precipitation. So the growing season looks to continue through at
least early October over the area.
07
&&
.AVIATION...  (For the 00z TAFs through 00z Monday Evening)
Issued at 632 PM CDT Sun Sep 21 2025
A large area of showers and storms will move into the area and
affect all the TAF sites this evening. HiRes solutions suggests
this will definitely affect SPI and DEC, so will have TEMPO groups
for those two TAFs. PIA, BMI, and CMI will have PROB30 this
evening for now, but as convection evolves over the next couple
of hours, TEMPO groups could be added. Cigs and Vis will be VFR,
but vis of MVFR will be possible when storms are present. Models
show that VCSH will be possible through the rest of the night at
all TAF sites until tomorrow morning. Then overcast skies around
6kft will persist tomorrow during the day. Winds will be southwest
through the night but become more southerly tomorrow during the
day. Wind speeds will be 10kts or less.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS ILX Office Area Forecast Discussion