textproduct: Central Illinois

KEY MESSAGES

- Isolated to scattered light rain and patchy drizzle northwest of the IL river early this afternoon, will track southeast across the rest of central/southeast IL into this evening, bringing little to no measurable accumulation.

- Widespread Frost and Freeze This Weekend: High confidence in cold overnight temperatures falling into the upper 20s and lower 30s Friday night and lower 30s Saturday night. - Clouds decrease during Friday, with dry and quiet weather expected Friday through the middle of next week, as daytime highs rebound into the low-mid 60s during much of next week.

DISCUSSION

Issued at 150 PM CST Thu Nov 5 2026

A potent 500 mb shortwave trough over Hudson Bay and Ontario Province was digging southward into the western Great Lakes basin and southwest into KS. An associated cold front was over nw IL into central MO and will track se across central IL into this evening and through southeast IL by early overnight. Overcast low clouds blanket central IL from I-70 north while still mostly sunny skies southeast of I-70 early this afternoon. Radar mosaic and surface obs show patchy light rain showers and drizzle nw of the IL river and extending into southeast parts of WI/IA and pivoting se toward central IL. As the cold front sweeps se through the IL river valley rest of this afternoon and and into southeast IL by early overnight, will see low clouds increase in southeast IL rest of today, while chances of light rain showers/drizzle spread se as well over the CWA. Rainfall measurements will be very light if they occur. Breezy WSW winds gusting 15-25 mph ahead of cold front to turn NW behind the front and bring in colder air. Lows overnight mostly in the lower 40s, with some upper 30s northern CWA and near 45F from highway 50 south in southeast IL.

A 545-550 decameter 500 mb low moving from Ontario into southeast lower MI Fri afternoon, will keep its light precipitation ne of central IL while low clouds decrease from the north during the day Friday as skies become partly to mostly sunny. Cool highs in the upper 40s north of I-72 and lower 50s from I-72 south. Breezy NNW winds will add a fall chill to the air. A 1025 mb Canadian high pressure ridge to settle southeast into the upper Midwest Friday and into MO and ridging over IL during Friday night and Saturday. Winds to lighten up during Friday evening with mostly clear skies and dry continental air mass to bring coldest night of the season. Late-season gardening interests should prepare for widespread frost/freeze potential Friday night and Saturday night. A widespread freeze likely over much of CWA by dawn Saturday with lows 28-32F. Still cool Saturday with mostly sunny skies, highs in the lower 50s (near 55 at Lawrenceville). We should have lighter nw winds than today and Friday with high pressure ridge nearby. Another frosty night Saturday night with lows in the lower 30s.

Surface high pressure ridge shifts south/se of central IL during Sunday with WSW return flow starting a warming trends. Highs Sunday around 60F to lower 60s with a fair amount of sunshine and not too strong of winds so a pretty nice fall day for outdoor activities. Ensemble consensus (GEFS/EPS) shows strong agreement on a fairly quiet fall weather pattern over IL during during much of next week, with temperatures trending above normal with highs in the low to mid 60s. A blocking regime pattern over withe Gulf moisture cutoff from returning to IL and disturbances periodically passing well ne of central IL.

The Climate Prediction Center (CPC) 8-14 Day Outlook for Nov 12-18th has a 65-75% chance of above normal temperatures over central and southeast IL and 33-40% chance of below normal precipitation.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1011 PM CST Thu Nov 5 2026

IFR ceilings will improve to MVFR at KBMI-KDEC-KCMI over the next couple of hours, then MVFR ceilings will dominate the central IL terminals through much of Friday morning. Drier air working in from the north will eventually scatter out the ceilings, with most guidance showing this occuring by late morning. NW-NNW winds behind the departing cold front will persist through the forecast. 10-15 kt speeds will be common, with a decrease under 10 kt after 00z.

ILX WATCHES/WARNINGS/ADVISORIES

None.