textproduct: Central Illinois

KEY MESSAGES

- Beneficial rainfall is on tap this week. The 00z Mar 2 LREF indicates a 50-70% chance of greater than 2 inches of rain from today through next Sunday morning along and south of a Rushville to Rantoul line.

- Strong thunderstorms are possible Wednesday. The highest probability for severe weather (greater than a 15% chance) will focus from northeast Texas into the Ozarks.

..Strong Thunderstorms Wednesday

00z Mar 2 models have come into better agreement concerning the track and timing of low pressure across the Midwest by mid-week. The GFS has slowed the system from its previous runs while the ECMWF has quickened it a bit...with consensus taking the low through the Illinois River Valley Wednesday night into Thursday morning. The persistent frontal boundary will be stalled across the heart of central Illinois on Wednesday, and as short-wave energy approaches from the southwest, convection will re-develop along and near the front late Wednesday afternoon into Wednesday night. As has been seen over the past several forecast cycles, the strongest instability and shear will coincide further upstream from eastern Texas/Oklahoma into the Ozarks during the day Wednesday...which is where SPC has upgraded to a Slight Risk for severe weather. Further northeast, instability will be lesser across central Illinois (MUCAPE 200-400J/kg): however, shear will be strong (0-6km bulk shear 40-50kt). This may be enough to result in a few strong thunderstorm cells capable of marginally severe hail/wind gusts along and south of I-72 Wednesday evening. By the time the surface low pressure arrives later Wednesday night into Thursday morning, daytime instability will wane and the severe risk will decrease substantially.

Barnes

AVIATION

(For the 12z TAFs through 12z Tuesday Morning) Issued at 545 AM CST Mon Mar 2 2026

11z/5am obs show IFR ceilings at KSPI/KDEC and MVFR further north at the I-74 terminals. While the low cloud cover is widespread across central Illinois, skies have cleared across northeast Illinois/northwest Indiana. With boundary layer flow from the E/NE, will need to keep an eye on KCMI/KBMI as there is a chance those sites could rise to VFR later this morning before the flow gradually veers to E/SE this afternoon and evening. Further west, HRRR/RAP suggests KSPI will be locked in with IFR ceilings perhaps briefly improving to MVFR this afternoon. As winds become E/SE, any temporary ceiling improvement will be erased as the very low overcast returns tonight. Latest CAMs tend to keep most of the showers associated with an approaching warm front just S/SW of the TAF sites late in the period, but have opted to include VCSH at both KSPI and KDEC after 08z/09z.

Barnes

ILX WATCHES/WARNINGS/ADVISORIES

None.