SWOP Weekly Weather Discussion

HEADLINE

The warm fall weather will continue for the foreseeable future...while a pattern shift brings much-needed rainfall to central Illinois by the first week of November.

DISCUSSION

The main branch of the polar jet stream continues to stay well to the north across Alaska and the northern Canadian provinces while much weaker upper-level flow is noted further south over the U.S. While a persistent and anomalously strong ridge of high pressure is still dominating the weather east of the Mississippi River, a pair of short-wave troughs will gradually flatten the ridge over the next couple of days. As the waves pass to the N/NW of Illinois, a weak cold front will get nudged southward...potentially bringing a few light showers on Thursday, October 29th. The upper flow will then become west-southwesterly by the end of the week, which will allow a stronger southern-stream wave to lift northeastward out of Texas and bring a better chance of showers over the Halloween weekend.

After that, medium range models are suggesting a wetter weather pattern for next week. The polar jet is progged to temporarily dip southward into the Pacific Northwest this weekend before resuming its far northward trek next week. All models are showing a cut-off upper low developing in the wake of the retreating jet stream...with the low slowly meandering into the Midwest early next week. While the exact strength and timing of the low remain in question, the synoptic pattern favors a northward transport of deep-layer moisture from the Gulf and thus an opportunity for widespread beneficial rainfall. Despite the increased cloud cover and rain chances, temperatures will remain above normal for this time of year through at least the end of next week...as cold air remains locked in place over the North Pole.

The latest 6-10 day outlooks (Nov 1-5) from the Climate Prediction Center (CPC) suggest ABOVE normal temperatures and ABOVE normal precipitation across central Illinois.

Issued: 10/26/26