Peoria, Ill. (WMBD) — The parade of powerful storm systems the past few weeks has resulted in severe storms, heavy rain and heavy snow across the country. These storm systems have generally brought heavy rain and strong storms to Central Illinois, including a few tornadoes in the Champaign area on Monday. However, the next system could bring winter weather back to the region.
- Rain develops Thursday night
- Change to snow expected Friday morning, especially west of the I-55
- Heavy rain likely with a widespread 1-2 inches expected
- Highest snowfall amounts west of the Illinois River
- Frequent gusts over 45 mph possible Friday
While additional changes in storm track (north or south) are likely over the next couple of days, the storm track over the last 24 hours has trended a little further north which will mean the area will see a longer period of rain. That said, as temperatures drop on Friday a changeover to snow is likely west of the Illinois River Friday morning and early afternoon.
Rain is likely to develop not long after midnight Thursday night. Rainfall rates could approach a half inch an hour with locally higher rates possible with any thunderstorms that develop. Rain could occasionally mix with snow near Galesburg, but most locations will likely see rain throughout the night.
Winds will also be breezy, blowing from the northeast at 10-20 mph with gusts up to 35 mph likely.
As the area of low pressure moves through Illinois, temperatures aloft and near the surface should cool allowing for a change over to snow from west to east across the region. As of now, no freezing rain is expected during this transition. For areas along and west of the Illinois River the change over should occur between 9 am and noon, then between 10 am and 3 pm further east. All precipitation should come to an end by sunset.
Wind speeds are expected to increase Friday morning as the shift from the northeast to the northwest as the area of low pressure moves through the state. Winds will be sustained at 15-25 mph with frequent gusts of 40-50 mph likely. Wind speeds should decrease not long after midnight.
Rainfall Forecast and Snowfall Outlook
While exact rainfall amounts are unclear, it’s likely most of the area will see somewhere between 1 and 2 inches of rain/melted snow, heaviest towards I-72.
The snowfall forecast remains a bit more uncertain as the storm track, timing, and change over time will impact snow accumulations. Making matters even more complicated is the recent stretch of warm weather which we know will lead to a great deal of melting. The fact that the change over to snow is likely to occur after sunrise on Friday will likely act to limit the amount of accumulation that takes place and preventing significant accumulations across Central Illinois.
The latest EPS Ensemble Snowfall Accumulation Probabilities gives the Peoria area a 40-50% chance of receiving at least 1 inch of snow and a 30-40% chance of seeing at least 3 inches of snow. Of course, a shift further south would result in an earlier change over to snow and therefore more accumulation and greater impacts.
While heavy snow is not expected to have a significant impact on Central Illinois at this time, the heavy rain and gusty winds will. Heavy rain falling on already saturated soils will contribute to excessive runoff and localized flooding. In addition to that, the strong winds could bring down shallow rooted trees, especially where soils are overly saturated.
Additional changes in storm track are likely in the coming days, but based on the information available now this is what we know. Be sure to monitor future forecast closely as a subtle shift in track of a 100 miles will mean significantly different weather conditions.