Brighton, IL 62012 Weather

Key messages

- Warm and dry conditions are expected through Thursday.

- Chances of light rain showers increase this weekend, but better chances of a widespread beneficial rain event come early/mid next week.

Short term

Issued at 307 AM CDT Wed Oct 28 2026

Warmer temperatures are expected this afternoon due to increasing low-level warm air advection along with more plentiful sunshine. High temperatures in the mid to upper 70s are expected, or about 15 degrees above normal for the date.

A weak midlevel shortwave is forecast to move across the Upper Midwest overnight tonight, helping to increase mid/high level clouds across northeast Missouri and west-central Illinois. At the surface, a cold front is forecast to move southeast into northeast Missouri and west-central Illinois Thursday morning. A few spot showers cannot be ruled out, but the timing of the front is not favorable in our region as the better mid/upper level forcing is to our north and low-level moisture convergence decreases late tonight into Thursday morning near the frontal boundary. Ahead of this front, highs are expected to top out in the low 80s. Weak surface convergence along the boundary along with a subtle midlevel impulse may yield a few isolated rain showers, and possibly a rumble of thunder, during peak heating.

Long term

Issued at 307 AM CDT Wed Oct 28 2026

(Thursday Night - Sunday)

The cold front is expected to stall by Thursday night across southeast Missouri and southwest Illinois before pushing back northward early Friday. Chances of rain showers increase along/poleward of the retreating boundary as low-level moisture convergence strengthens and a weak midlevel shortwave moves out of the south-central Plains. The exact placement of the west-east boundary varies slightly amongst deterministic guidance (~50 miles), but the most likely location Friday afternoon is near the I-70 corridor. This means that the best chances (50-70%) of light rain showers on Friday are across northeast Missouri and west-central Illinois. The increased clouds/rain chances north of the front should help create a north-south temperature gradient across the region, with highs near 70 degrees across northeast Missouri and west-central Illinois and closer to 80 degrees south of I-70.

Forecast uncertainty is higher for the weekend, as it now looks like individual weak midlevel impulses will come across the Mississippi Valley instead of one stronger shortwave trough. The track and timing of each individual impulse is not certain, which is why there is a fairly long duration of chance (30-50%) PoPs this weekend. Any rain that does occur this weekend though does look light and showery, with certainly more dry time than not this weekend. Probabilities for both measurable (>=0.01") and 0.25"+ amounts on the LREF have dropped about 10-15% compared to this time yesterday. Cooler high temperatures are expected regardless due to thicker cloud cover, with highs forecast to be in the upper 60s to low 70s.

(Sunday Night - Tuesday)

Ensemble guidance shows a deeper trough carving out across the desert Sunday night into Monday. Cluster analyses of the 500-hPa pattern diverge sharply by Tuesday with the track and timing of this feature. Three of the four clusters show a closed, possibly cutoff, mid/upper level low forming across the central Plains. These clusters comprise 83% of the LREF membership, so the signal is pretty strong. A closed mid/upper level low forming to our west should lead to deep, anomalous southerly flow aloft. An increase in deep-layer moisture along/ahead of a slow-moving frontal boundary is a good recipe for a long-duration beneficial rain event across the area. Probabilities through Tuesday of at least 0.50" of rain range from 65-90% from southeast to northwest. Those numbers jump even further if you go out through the middle of next week as the potential for a deep, closed low could portend to it impacting the region for at least a few days.

Aviation

Issued at 639 AM CDT Wed Oct 28 2026

Periodic fog may continue to impact KSUS over the next 1-2 hours. Otherwise, dry/VFR conditions are expected along with predominantly light southerly winds.

Watches, warnings and advisories

MO: None. IL: None.