East Saint Louis, IL 62201 Weather

Key Messages

- Seasonably warm temperatures with mostly dry conditions will continue through Friday.

- Chances of light rain return this weekend, but a widespread significant (0.50+") rain is not likely.

Short Term

Issued at 249 AM CDT Mon Oct 26 2026

GOES-19 nighttime microphysics satellite imagery shows thickening cirrus clouds moving from southwest to northeast toward the Mississippi Valley. This increase in high-level cloud cover has limited the nocturnal temperature drop slightly overnight, with current readings on average about 3-5 degrees warmer than 24 hours prior. Increasing and thickening high clouds are forecast through the morning hours, before some clearing moves into western sections of the CWA during the afternoon. Due to the aforementioned clouds, high temperatures today are not expected to be as warm as Sunday, with readings topping out mostly in the mid 70s. There may be a few spots that get into the upper 70s though in central Missouri if the clearing works its way in a bit sooner than forecast.

A midlevel shortwave trough is forecast to move slowly out of the south-central Plains and across the mid-Mississippi Valley late tonight through Tuesday evening. The main impact with this feature should be a notable increase in midlevel clouds, which should lead to slightly cooler temperatures (low to mid 70s) on Tuesday. A few spotty sprinkles cannot be ruled out, but the mid/upper level forcing for ascent is not that strong and there is a very deep (15+ kft AGL) layer of dry air to overcome.

Long Term

Issued at 249 AM CDT Mon Oct 26 2026

(Tuesday Night - Friday)

The pattern remains largely stagnant through the end of the work week with our region sitting beneath quasi-zonal flow aloft. A weak cold front is forecast to approach parts of northeast Missouri late Wednesday night before stalling out and lifting back north as a warm front later in the week. There is a low chance (20-30%) of rain showers and possibly a thunderstorm or two in the vicinity of this cold front, mainly across northeast Missouri and west-central Illinois.

Temperatures are forecast to moderate through Thursday, with most locations getting back into the low 80s to the southeast of the cold front. At least slightly cooler highs (upper 70s to near 80 degrees) are expected on Friday, mainly due to increasing mid/high level clouds.

(Friday Night - Sunday)

Ensemble guidance is in reasonably good agreement that another midlevel shortwave trough will move across the south-central Plains into the mid-Mississippi Valley this weekend. There remains some subtle timing differences, but the shortwave looks somewhat reminiscent of the one working its way across the region early this week. The shortwave itself is not particularly strong or organized, and gradually weakens with time as it gets sheared out as it moves into more confluent flow aloft. The best chances (30-50%) of light rain showers are on Saturday afternoon/night as a wing of relatively modest low-level moisture convergence moves from southwest to northeast. At this point in time, the rain looks to stay on the light side with plenty of dry time this weekend. The chances of a widespread, significant (0.50+") rain looks very low. The latest LREF probabilities for 0.50+" through this weekend are only in the 10-25% range from north to south, and have been dropping over the past 24-36 hours.

Aviation

Issued at 1140 AM CDT Mon Oct 26 2026

Dry and VFR conditions with light generally southerly winds will persist through the end of the TAF period.