Springfield, Illinois 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

174
FXUS63 KILX 040748
AFDILX

Area Forecast Discussion
National Weather Service Lincoln IL
248 AM CDT Mon May 4 2026

.KEY MESSAGES...

- There is a 50-80% chance southwest winds gust over 35 mph
  today near and east of the I-55 corridor, promoting patchy
  blowing dust. This can result in localized, sharply reduced
  visibilities for motorists.

- Scattered thunderstorms are forecast this evening into
  tonight. There is a level 1 of 5 (marginal) risk for locally
  large hail and damaging wind gusts, mainly during the 7pm to
  1am timeframe.

&&

.DISCUSSION...
Issued at 246 AM CDT Mon May 4 2026

***** BREEZY AND WARM WITH PATCHY BLOWING DUST TODAY *****

At 230am, scattered thunderstorms were ongoing across areas near and
south of a roughly Jacksonville to Paris line where 30-40 kt
effective bulk shear and 250-500 J/kg MUCAPE rooted around 850mb
were apparent on SPC`s mesoanalysis page. Radar presentation would
suggest the cores of the strongest storms are producing small hail,
though the general trend is toward weakening storms as instability
continues to wane. CAMs suggest this activity will wane through
daybreak, though the leftover outflow boundary may serve as a focus
for a few lingering showers through afternoon by which time surface
heating will bring a resurgence of instability. The High Resolution
Ensemble Forecast (HREF) and Rapid Ensemble Forecast System (REFS)
mean SBCAPE climb to 1000-1500 J/kg by late afternoon, though
forecast soundings also advertise a capping inversion which should
inhibit realization of that instability until LLJ ramps up during
the evening.

With enough sunshine, deep mixing will promote temperatures warming
into the upper 70s to low 80s by mid afternoon. It will also result
in gusty southwest winds, with Bufkit soundings showing winds
approaching 40 kt (46 mph) at the top of the mixed layer - a
reasonable estimate for peak gusts - in east central Illinois. Given
we had blowing dust yesterday afternoon with similar wind speeds, we
elected to issue a Blowing Dust Advisory for areas north of I-70 and
east of the Illinois River, where the risk appears greatest due to
soil type and expected winds. (While several of the counties in this
Advisory received rain from storms early this morning, the spotty
nature of that rainfall and tendency for the near surface topsoil to
quickly dry out made us think the potential is still significant
enough, particulary along highways, to issue.)

***** STRONG STORMS TONIGHT, RAINY AND COOL TUESDAY *****

As a 40-50 kt LLJ ramps up ahead of a cold front this evening,
scattered storms are forecast to develop, posing primarily a risk
for locally damaging winds and large hail given steep mid level
lapse rates and dry air in both the mid levels and below cloud bases
(around 850mb). Given high LCLs, the tornado risk appears low (less
than 2%), but SPC maintains a level 1 of 5 (marginal) risk for wind
and hail. After midnight, coverage of storms is slated to
increase while instability gradually wanes, lowering the risk
for severe weather but bringing more widespread rain, which will
continue in waves into tomorrow night. While this rainfall will
be spread out over 24+ hours, we can`t fully rule out
hydrological issues south of I-72/Danville where some spots
received up to 5 inches last week and where NBM gives a 5-15%
chance for more than 2 inches; WPC has a level 1 of 4 (marginal)
risk for excessive rainfall near and east of a roughly
Shelbyville to Danville line. Behind the cold front tomorrow
into Wednesday, it`ll be quite chilly with afternoon highs in
the mid to upper 50s.

***** STAYING COOL WITH LOW PRECIP CHANCES LATE WEEK *****

The parent upper level trough will linger over Ontario late week,
with shortwaves orbiting it and offering the local area with
periodic, low (15-30%) shower chances and shots of chilly Canadian
air through the early part of the weekend. While global models and
their respective ensembles differ in how long it will take for this
upper level trough to retreat to the northeast, NBM`s
probabilistic distribution for daily high temperatures shifts
up each day Thursday through Saturday. For example, the 25th
percentile (75% chance of warmer temperatures) in Lincoln
increases from 57 Thursday to 65 Friday to 70 Saturday.

&&

.AVIATION /06Z TAFS THROUGH 06Z TUESDAY/...
Issued at 1230 AM CDT Mon May 4 2026

VFR conditions will prevail at all TAF sites most of the 24hr
period. High cirrus will be the rule for most of the sites, but
SPI will see broken mid clouds since it is closer to the
convection out there currently. As the low level jet veers over
the area, additional showers are possible in the morning, but
for just SPI, DEC, and CMI. This will last into the afternoon.
Then a break in the precip will occur until after 00z, when
scattered storms are possible at all sites. Winds will be south
to southwest through the period. Wind speeds will be less than
10kts now, but increase during the day, with gusts over 30kts.
Winds will decrease during the evening, but still some gusts
over 20kts.

&&

.ILX WATCHES/WARNINGS/ADVISORIES...
Blowing Dust Advisory from 11 AM this morning to 6 PM CDT this
evening for ILZ031-037-038-041>048-050>057-061.

&&

$$

KEY MESSAGES...Bumgardner
DISCUSSION...Bumgardner
AVIATION...Auten