What is the farthest south “polar expresses” have driven?
-Vic Mazylewski, Shorewood
Arctic outbreaks routinely penetrate into the Deep South and a few will sweep through Florida and Texas. However, some cold surges have reached Central America and the northern portion of South America. Topography plays a limiting role, with Central American mountain ranges halting the southern push of cold air. Some of the natural barriers include the Sierra Madre range and the Costa Rican mountains south of Lake Nicaragua. Afew vigorous cold outbreaks have made it to about 7 or 8 degrees north latitude where they were finally halted by the mountains of Colombia. At those low latitudes, the cold air is very shallow and greatly modified, and only lowers the temperature a few degrees.
Lake effect snow could take another swipe at Illinois shoreline communities today, including downtown Chicago and portions of the city. While little or no accumulation is expected, the return of some flurries or snow showers may come as a bit of a surprise to many.
Surface winds out of the northwest are battling northeast winds aloft. The northeast winds may overcome the surface flow at times, allowing for some lake effect snow showers to return to Illinois.
Northwest Indiana will remain the most favorable area for lake effect snow today. As of 7AM, Warnings are still posted for Porter and LaPorte Counties, but some accumulation may occur as far west as Lake County, Indiana.
Lake Michigan may be the culprit at times for additional snow across the Chicago area, but it also spares many from the worst of an arctic outbreak.
There was an impressive 40 degree temperature swing across northern Illinois and northwest Indiana this morning. The low this morning in Rock Falls, IL plummeted to -18 F, while the temperature at Burns Harbor, Indiana did not fall below 20 degrees, on the positive side of zero. The low at the Chicago Lakefront was 16F.
The main reason for the warmer temperatures: The mainly unfrozen waters of Lake Michigan that vary anywhere from 32 to 38 degrees above zero.
Here are some of the area lows on this Saturday morning:
-18 Rock Falls/Sterling, IL
-18 Rochelle, IL
-11 Lacon, IL
-8 Kankakee, IL
-5 DeKalb, IL
-3 Minooka, IL
+6 Chicago (O’Hare)
+9 Chicago (Midway)
+16 Chicago Lakefront (Northerly Island)
+20 Michigan City, Indiana
+22 Burns Harbor, Indiana (Porter County)
We don’t need to be told that we’ve been contending with a cold and snowy winter, but a review of Chicago’s weather records reveals that it’s been much worse on many occasions in the past. Through Jan. 8, this winter’s average temperature, 23.9 degrees, ranks merely 28th coldest since 1870-71, 27 winters have been colder in the Dec. 1-Jan. 8 period; the coldest: 16.4 degrees in 1983-84. Seasonal snowfall through Jan. 8 stands at 28.3 inches sufficient to generate complaints from snow-weary residents, but only 8th snowiest. The greatest: 52.4 in 1951-52.
Lake snow smothers north Indiana
Lake-effect snows have been daily occurrences since Dec. 26 in the snow belt regions of northern Indiana. Snow totals there are impressive, even by the snowy standards of those areas. South Bend, Ind., recorded 23 inches during the first week of 2010, second only to the 27.3-inch total that fell during Jan. 1-7, 1999. Unofficial accumulations of 30-40 inches in the Dec. 26-Jan. 7 period have been reported in northern Indiana locations within 15 miles of Lake Michigan.
– By Richard Koeneman, WGN-TV Meteorologist
Is it possible to have a winter with temperatures averaging below normal despite El Nino?
It is possible. We’re less than halfway through the current winter and so the jury is still out, but the winter thus far has been running considerably colder and snowier than normal. El Ninos (above-average water temperatures in the tropical Pacific Ocean) have occurred 17 times since 1950 and an 18th began in July 2009. It continues at present. El Ninos persist a year or two, with worldwide weather consequences.
On balance, Chicago’s “El Nino winters” tend to be mild and tranquil, but that means only that significantly harsh winter weather conditions, although they still occur, visit the city less frequently than usual and with lessened duration. On average, about 60 percent of Chicago’s El Nino winters deliver above-normal temperatures and below-normal snowfall.
Jeremy and Sarah of Lake in the Hills sent us this beautiful picture of sunset after our recent snowstorm. Thank you both for the great photo!