May 20--Rain falling through cool, dry air brought brief bouts of sleet to parts of the Chicago area Wednesday afternoon, according to the National Weather Service.
Sleet was observed by weather forecasters at their Romeoville office. One of the forecasters ran into icy conditions on his way to work from LaSalle County, according to weather service meteorologist Casey Sullivan.
"When the air's as dry as it's been, when rain starts falling and it evaporates into the dry air, cooling, that can cause the rain to freeze," Sullivan said.
The phenomenon is brief, usually at the beginning of a rainstorm, he said.
Temperatures Wednesday afternoon were cool for May -- in the mid- to upper-40s -- about 20 to 25 degrees below the normal high of 71.
The scattered rain was expected to end this evening. After a cool overnight, with lows in the lower 40s, it's expected to be closer to normal on Thursday, with a high near 69, coming close to 70 in some places.
Friday is expected to be cooler -- closer to 61 degrees -- and the weekend will start with a sunny Saturday, topping out at 73 degrees. Rain is expected to move into the area Saturday night, with highs Sunday again around 73, but with a chance of thunderstorms.
For more information, see the Tribune's weather page.
