By Meteorologist Richard Koeneman
Winter returns to Chicago on Tuesday. Borne by northwest winds gusting more than 30 mph, arctic air will blast into the city and change morning rains to snow by Tuesday afternoon. And by Thursday, the city could see the lowest temperatures thus far this winter.
It's not often that the contrast between back-to-back winters has been as sharp as this year to date versus last year. As of Jan. 16, the city had officially logged 7.0 inches of snow, versus 22.8 inches last year. Monday's high temperature, 45 degrees, was the 30th day this meteorological winter (which began Dec. 1) that the temperature was 40 degrees or higher. Last winter logged only three such days during the comparable period. And meteorological winter has thus far has averaged a startling 11.8 degrees higher than last winter.
A low, dense stratus overcast, fog, drizzle and very light rain - they are the dreary result of mild, moist air streaming across our snow-covered terrain. Were it not for that cloudiness and blanket of snow, Chicago's Monday afternoon temperatures could shoot for 50 degrees. But as it is, we'll have to settle for readings approaching 40 degrees - and that is nine degrees above the day's normal high. Don't get used to it: Borne along by powerful westerly winds averaging 70 mph three miles aloft, a weather disturbance that is crossing the Rocky Mountains on Monday will direct a surge of much colder air toward Chicago by late Monday night. That sets the stage for another bout of snow and plunging temperatures on Tuesday. The snow is not likely to be a big deal - best estimate is that it will be an inch or two - but enough to make a difficult commute Tuesday morning.
By Meteorologist Richard Koeneman
Chicago area minimum temperatures early Saturday morning are forecast to be the coldest of the winter season to date, and the usual wide range of metropolitan low temperatures will again be apparent. Expect lows from near zero in the coldest outlying areas to about 12 degrees in downtown Chicago. A clear sky Friday night would yield subzero readings across the city area, but lingering cloudiness is expected to slow the temperature plunge. The current surge of cold air is timely in the sense that, on average, the ten-day period of Jan. 16-25 is the coldest portion of the winter season.
The weather remains active across much of the United States. Locally, the metropolitan seven-day forecast contains the mention of three separate precipitation occurrences: light snow Saturday, a rain-to-snow event Monday into Tuesday and snow Saturday (Jan. 12).
By Meteorologist Richard Koeneman
In an average winter, 14 inches of snow -- 38 percent of the 37 inches that the city receives in a full snow season -- has come down by January 12. Snow production this winter has been decidedly lackluster (only 1.9 inches), but the season's first significant snowstorm arrives today and the seasonal snow total is likely to triple by Friday. Falling temperatures, northwest winds gusting above 30 mph Thursday afternoon and night, and 3-7 inches of wind-driven snow by Friday afternoon will remind us that this is, after all, January in Chicago. Snow begins in earnest by about noon Thursday and conditions will deteriorate considerably during the afternoon and evening. Although this storm is garnering disproportionate attention because it's the season's first major snow event in a relatively snow-free winter, it's certainly not in the league with last February's blizzard.
By Meteorologist Richard Koeneman
A January day with temperatures more than 20 degrees above normal is noteworthy in Chicago; the prevailing feeling is that "We've cheated winter out of another day." Tuesday's high temperature of 52 degrees at O'Hare International Airport bested the day's normal high by 21 degrees --- and it's about to happen again. Wednesday afternoon's high is expected to again hit 52, and that puts the city in rare territory --- back-to-back days above 50 degrees during the second week of January have occurred here only eight times in the last 141 years.
But winter is expected to return with a vengeance Wednesday night as Arctic air powers into the area. On Thursday, the cold air will be accompanied by strong northwest winds, bitter wind chill temperatures and, potentially, several of snow. Though not especially horrible by January standards, it will be an abrupt reality check.
By Meteorologist Richard Koeneman
It's not often that Chicagoans can bask in the relative warmth of a 50-degree day in January, but Tuesday's expected high temperature of 54 degrees, though highly unusual, is not without precedent. In records dating from 1871, Chicago's official thermometer has risen to at least 50 degrees on 39 days during the second week of January (Jan. 8-15). On average, that's one 50-degree day out of 25.
Such anomalous warmth cannot last, of course, and a powerful surge of arctic air is headed toward Chicago. Cold air is forecast to arrive Wednesday night, sending temperatures crashing, but not until Wednesday afternoon readings climb into the lower 50s for a second day. Temperatures fall through Thursday, and Friday's predicted afternoon high, 22 degrees, will be the city's lowest daytime temperature in 11 months (since of high of 16 degrees on Feb. 10, 2011).
By Meteorologist Richard Koeneman
Weather-hardened Midwesterners understand that a characteristic of the region's tempestuous winter climate is abrupt and occasionally unpleasant weather changes. The winter thus far has been surprisingly deficient in that regard. We've all taken notice of the unusual dominance of mild temperatures and relatively storm-free weather that the winter has offered us thus far, but that's about to change.
A major weather pattern change is in the works: The week will start mild and finish cold, and the mid-week transition is to prove interesting. Chicago's temperatures shoot into the 50s on Tuesday, just before the arrival of a strong surge of arctic air on Wednesday. Some forecast information suggests the possibility of 3-6 inches of snow across the area late Wednesday into Thursday. Arctic air that arrives in strength Thursday will dominate area weather through the weekend.
By Meteorologist Richard Koeneman
Chicago's mild and snow-free winter rolls on, and area residents basked in the relative warmth of Thursday's afternoon readings that ranged from the middle 40s to upper 50 in the city area. Since 1871, only eight years produced higher temperatures on January 5 than the official high of 49 degrees as registered at O'Hare International Airport. Unseasonable though Thursday's readings were in the Chicago area, temperatures soared into the 60s from the Dakotas to Kansas, and, incredibly, a few communities topped 70 degrees. Somewhat cooler air will be spreading toward Illinois on Friday and a frontal boundary that marks the advance guard of that air mass will push across Illinois during the afternoon, attended by increasing cloudiness. Early afternoon temperatures in the lower 50s are likely before that cooler air makes its presence felt. A cooling trend then persists through the weekend before milder air returns early in the work week.
