The high of 13 degrees registered at O’Hare International Airport on Friday represented a 31-degree drop from Thursday’s peak reading. The surge of polar air arrived on west winds that gusted to 50 mph or more Thursday evening. Like last week’s polar plunge, the current influx of arctic air will be brief. High pressure will dominate our weather Saturday, allowing diminishing winds and ample sunshine to moderate the chilly air mass. Afternoon temperatures are expected to peak at least 12 degrees higher than on Friday. Cloudiness is to increase Saturday night as the next in a series of weather disturbances approaches from the west. Though weak in comparison to the storm systems of this past week, accumulating snow can be expected to spread over a swath of the Midwest by Sunday afternoon, with 1 to 3 inches likely across the metro area by evening.