An unusually strong area of low pressure is forecasted to quickly intensify across the Great Plains Friday, leading to a threat of severe weather in the Chicago area.
As that low-pressure area strengthens, the low will track more to the north than the east as it moves from western Kansas to northern Wisconsin Friday into Saturday, according to NBC 5 Storm Team Meteorologist Kevin Jeanes.
The result for Chicago will be a very warm and very windy start to the weekend, along with the possibility of strong-to-severe thunderstorms Friday night as one of a series of cold fronts approaches.
Here is a timeline on how things are expected to play out:
THURSDAY
An existing divide between cool and warm temperatures will continue as winds blow off of Lake Michigan Thursday.
Highs near the lake, including in the city of Chicago, will only be in the low-50s, while areas out to the west could see readings soar into the mid-to-upper 60s.
Local
Parts of the area south of Interstate 80 could even eclipse 70 degrees.
FRIDAY AFTERNOON
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A warm front will push north of the Chicago area Friday, allowing temperatures to soar into the 70s Friday afternoon.
It will still be slightly cooler near the lake in Cook & Lake counties with a south/southeasterly wind skimming across western Lake Michigan.
Wind gusts could exceed 40 mph at times late in the day; well before thunderstorms arrive. Most of Friday should be bright and sunny under fair weather clouds.
FRIDAY NIGHT
The risk of severe weather will depend on how storms develop out of Missouri into western Illinois Friday afternoon, along with how much warm air mixes vertically in our atmosphere around Chicago.
As of Wednesday afternoon, forecast models show an agreement on a line of storms pushing across northeast Illinois arriving in a window between 8 p.m. Friday and 2 a.m. Saturday. It is possible this line dissipates or splits before reaching the Chicago area, but it’s best to stay prepared, especially since this is the area’s first severe weather threat of the season.
Damaging wind gusts would be the greatest threat if everything holds together, and some isolated tornadoes are also possible.
The severe threat will be greater across central Illinois where there’s more instability in the atmosphere, according to the Storm Prediction Center.
SATURDAY
Rain should move out of the area before sunrise, but a few quick-moving showers can’t be ruled out in the afternoon and evening.
Most importantly for Saturday, it’s going to be a very windy day with some gusts over 50 mph possible. Winds this strong may be enough to cause some power outages. Gusts will be strongest late-morning and early-afternoon before getting lighter in the evening.
Temperatures still should reach the low to mid 60s in the afternoon.
SUNDAY
Another (but drier) cold front drops through Saturday night which ushers in much colder air for Sunday. Temperatures will top-out in the low 40s with northwest gusts around 25 mph Sunday afternoon.
