Rock Falls, IL Weather

Key Messages

- Above normal temperatures and dry conditions are forecast into early next week, with a brief cool down possible toward the middle of the week.

Short Term

Issued at 137 AM CDT Fri Oct 23 2026

As a 500 mb trough strengthens over the Intermountain West, the 500 mb ridge that has been overhead for several days will amplify. This trough, while not directly impacting the area, will influence weather patterns through the next couple days. The first of these impacts will be a tightening surface pressure gradient today and Saturday between high pressure over the eastern US and a developing surface cyclone over the Rockies. As a result, both today and Saturday will feel breezy with gusts of 15-20 mph.

Meanwhile, with the ridge in place and a mixed boundary layer, the only limiting factor to today's highs will be scattered high clouds on the periphery of the developing system's warm advection wing. This will not be enough to keep highs from reaching the mid to upper 70s, continuing our streak of above normal temperatures. With the increasing clouds and broad synoptic lift, a handful of CAMs have had an area of light showers extending from eastern Minnesota into northeast Iowa and as far south as the Highway 20 corridor Friday evening. However, any rain will likely result in virga via evaporation, due to dry low levels following a well-mixed boundary layer. As such, have kept PoPs below 5%.

As clouds lower and fill in overnight, lows will drop into the 50s, before returning to highs in the mid to upper 70s once more on Saturday.

Long Term

Issued at 137 AM CDT Fri Oct 23 2026

By Sunday, a strong low over Hudson Bay will dislodge high pressure from the Great Lakes, pushing it eastward. A diffuse frontal boundary from this system will sag southeastward from the northern Plains, eventually reaching the CWA by Monday and bringing a cooldown to at least part of the CWA. However, model timing still remains quite poor with regard to the front, resulting in a near 10 degree spread across the northwestern half. With this cooldown, highs are expected to fall into the mid 60s to low 70s but remain above the normal highs for late October.

Past Monday, while guidance has a wide spread regarding that pattern aloft, a return to a more active pattern is expected. Some models, such as the ECMWF, favor a west CONUS trough and eastern CONUS ridge, while the GFS favors a more shallow, near-zonal flow with embedded waves. While the pattern aloft remains unclear this far out, a continuation of our above-normal temperature streak appears possible through the end of October (50-55% chance) with highs in the 60s to 70s.

Additionally, while guidance continues to trend drier along the boundary on Monday, precipitation chances are above normal through the end of October. This was highlighted in the CPC 6-10 day outlook with a 40-45% chance of above normal precipitation. This lower confidence compared to temperatures is due to uncertainty in both timing and intensity of forcing for precipitation. What will favor these above normal chances, in addition to a more active pattern, is a more moist airmass with PWATs near 0.8-1.0 inches, or around the 75-90th percentiles.

Aviation

Issued at 1236 PM CDT Fri Oct 23 2026

VFR continues today through tonight with mainly clear skies expected. Winds will remain steady out of the south-southeast between 5-10 kts, with higher gusts up to 20 kts possible at CID and DBQ this afternoon.