I looked at the sky this morning and the clouds were moving fast. Does that mean there will be a storm?
Sam Ganzel (age 8)
Rapidly moving clouds do not necessarily mean a storm is coming. Clouds appear to be racing across the sky because they are close to you, in other words, they are low clouds and not very far above the ground. Here is an example to illustrate the point. You are able to see very low clouds — clouds generally within 500 feet of the ground — only when they are within a mile or two of you. If those clouds, at 500 feet, are moving at 25 mph, they will be within your field of vision for about 10 minutes, at most. But high, wispy cirrus clouds, often above 30,000 feet and moving at 60 mph, can be seen from 50 miles away. Despite their speed, it will take them at least 1 1/2 hours to move through your field of vision.
Arctic air tightens its grip across the Midwest Thursday. A highly-reflective fresh cover of snow all but assures sub-zero wind chills will dominate the day despite the presence of sunshine.
Sunlight typically heats air indirectly, warming the ground onto which it falls first. A fresh accumulation of snow defeats that process by reflecting solar energy back to space. Wednesday afternoon and evening snowfalls included 1 inch in Plainfield and Yorkville as well as at Schererville and Highland in northern Indiana. Other Wednesday snow totals included 0.9 inches at O’Hare, 0.8 at Peotone. 0.6 at Oak Brook and 1.2 inches in Portage Ind.
Computer trajectory forecasts, which track the movement of air indicate Thursday’s chill originated in the Dakotas 24 hours ago. There, temperatures flirted with zero Wednesday. With news snow in place, it’s likely the air mass will retain its arctic character as it arrives in Chicago allowing temperatures here to rise no higher than the teens and to drop sub-zero away from the lake Thursday night. Gusty northwest winds of 10-22 mph Thursday assure wind chills will remain between 0 and 12 below.
Arctic air deflecting major snow and ice storm south of Chicago
The blast of arctic air is having a major impact on the track of the latest Pacific storm to come ashore in the United States. The system emerges from the southern Rockies into the southern Plains Thursday and proceeds east assuring its formidable snows and accumulations of ice remain well south of Chicago. In Oklahoma, where residents basked in springlike 60s Wednesday, plunging temperatures and howling east winds are to deliver ice and snow Thursday. The storm’s impact may not completely bypass Chicago. Its winds are to interact with a Canadian high pressure producing a north-to-northeast flow which begins sweeping into Chicago off Lake Michigan late Friday through Saturday. Over that 28 hour period the potential for lake-effect snow showers and flurries rises here. Some accumulation is not out of the question.
El Nino taking a big bite out of seasonal snow tallies here
Each El Nino has its own character. The differences from one such period to the next can be formidable. But, as a general proposition, El Ninos are known to produce storms which crash into the West Coast—last week’s storm parade serving as a spectacular example—then tracking through the southern states. It’s a development which boosts cold season snowfall in the Plains but often slashes snowfall in the Midwest. Data from these regions on snowfall to date indicates how closely this season’s snowfall is tracking with many past El Ninos. Snowfall is substantially lower in Chicago and the area which surrounds it this year versus last. O’Hare’s snowfall (prior to Wednesday’s system) is more than 13 inches lower than a year. Other declines include Rockford: down 23.7 inches from a year ago, Milwaukee off 27.5-inches and South Bend with a seasonal tally down 23.2 inches.
My mother always tells me how much it was snowing just before I was born on Jan. 25, 1985, but she never wrote down any details. Just how bad was it?
Kathleen McCoy, Naperville
Though there was snow on the days leading up to your birthday, the real story in Chicago that month was the record cold. Over the three-day period from Jan. 16 to Jan. 18 the city received about 5 inches of snow. Another 1.2 inches fell Jan. 24 and an additional inch on your birthday, bringing the city’s snowpack to 8 inches. But, five days before you were born, on the morning of Jan. 20, the official thermometer plunged to minus 27 degrees, the city’s lowest reading ever, and coupled with strong winds, wind chills hovered near 80 below zero. Readings did not break freezing the rest of the month, which closed with a low of minus 12 on Jan. 31.
There is no doubt about it- winter has returned to Chicago after last weeks January thaw.
A period of light snow that began around mid-afternoon will be winding down this (Wednesday) evening. Total accumulation from this latest round of snow should be one inch or less. Strong west-northwest winds will result in some blowing and drifting of the light fluffy snow well into the night tonight.
There are no official advisories or warnings in effect, but some untreated roads may be quite slick during the evening commute.