A nasty storm system could cause issues in the Chicago area on Wednesday, but whether that precipitation will fall in the form or rain or ice all depends on how warm the temperatures are.
The NBC 5 Storm Team is tracking that system as it approaches the area, but the NOAA’s High-Resolution Rapid Refresh model (HRRR) and IBM’s Global-High Resolution Atmospheric Forecasting System (GRAF) disagree on what is going to happen on Wednesday.
The HRRR model is forecasting temperatures to be well-above freezing, making for a rain-only event with heavy accumulations of nearly 1.5 inches of rain or more in some locations.
The IBM GRAF model meanwhile is forecasting temperatures right around freezing, which could cause some serious ice accumulations, especially in the western suburbs and perhaps even in Chicago itself.
The worst of the system is expected to arrive Wednesday afternoon, and will largely move out of the area by Wednesday evening.
Here are more details on what each forecast will call for.
Local
HRRR Model
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The precipitation is expected to arrive in the Chicago area early Wednesday morning, and according to this model, that will fall in the form of rain, heavy at times.
The heaviest precipitation is expected to fall in the afternoon hours, with nearly an inch of rain possible between noon and 3 p.m., according to models.
The rain will eventually work its way out of the area by the evening hours, but some rain could still potentially fall in the northern suburbs.
When all is said and done, the heaviest rainfall totals would occur in the northern and western suburbs, with most areas seeing 1.5 inches of rain or more.
Further south, heavy rains will still fall, with well over an inch of rain expected in most locations.
IBM GRAF Model
The other model used by the NBC 5 Storm Team is predicting more of a mixed precipitation-based event, with some fairly significant ice accumulations possible if the temperature drops enough.
While snow is likely going to be limited to Wisconsin regardless, the possibility of mixed precipitation or freezing rain could seriously impact the area, especially in the western suburbs and in the city itself.
Some parts of Kane, DuPage and Cook counties could see up to a half-inch of ice accumulation or more, with areas south of Interstate 80 likely seeing lower accumulations thanks to slightly warmer temperatures.
