FORECAST FOR DEKALB AND VICINITY, 2/8/12, 11:25 AM Today...generally sunny. High of 33 degrees. Northwest winds becoming westerly this afternoon at 10-20 MPH. Tonight...clear. Low of 19 degrees. West winds 5-10 MPH. Tomorrow...sunny and becoming a bit blustery. High of 36 degrees. Southwest winds increasing to 12-22 MPH in the afternoon. Extended outlook...Friday through Tuesday... Friday...partly cloudy, windy and colder with a good chance of flurries or very light snow. Low around 20. High in the upper 20s, then falling in the afternoon. Saturday...sunny. Low of 5 to 10 above zero. High in the lower 20s. Sunday...sunny. Low around 10. High in the middle 20s. Monday...increasing cloudiness with a chance of light snow late. Low in the lower teens. High around 30. Tuesday...cloudy with a chance of light rain or snow. Low in the middle 20s. High in the upper 30s. **************************************************************************** CLIMATE DATA: Yesterday's high, 32 degrees; last night's low, 23 degrees. The average high/low temperature is 30/14. We have had a trace of rainfall equivalent and a trace of snow at the DeKalb campus over the last 24 hours ending at 7 AM this morning. Forecast was for 33/19 with a trace of snow, amended to include a very light mix of rain, sleet and snow, with little or no accumulation. We stayed a tad warmer last night than expected because clearing held off until the daylight hours of Wednesday. We have had a trace of rainfall equivalent this month. On average, we should see 1.55" of rainfall equivalent, including 7.3" of snow, by February 29. We have had 1.41" of rainfall equivalent so far this year. Our monthly snow total is a trace", and our seasonal snow total so far is 13.7". By February 29, our average annual liquid total should be 3.02". **************************************************************************** SEVERE/HAZARDOUS WEATHER OUTLOOK: Friday, an Arctic front brings highs down into the 20s, with wind chills in the single digits. With no snow cover, this will be mostly just annoying, but with the wind, wind chills will be significantly lower, dropping down to -10 to -15 on Saturday morning. Keep that in mind if you have any travel plans on Friday into Saturday. We could see a dusting of snow on Friday as well, possibly creating some slick or icy spots. **************************************************************************** PRECIPITATION: Friday: a trace of liquid equivalent and snow, and 60% coverage. **************************************************************************** FORECAST DISCUSSION: Well, that was a non-event, and the cold front that produced a whopping 10 snow grains, 12 raindrops and 2 ice pellets (sleet) that I saw yesterday is dissipating to our south. But on our surface maps this morning, we see the blue triangles of doom in central Canada, a cold front whose leading edge is racing southbound and will cross the border tomorrow, and then race through our area on Friday with a band or two of light snow, and considerably colder air this weekend. The good news is that any snow we get will be light, the weekend will be sunny, and the "real" cold weather with highs in the 20s will last for only 3 days before we warm up on Monday...to the point where we have to insert chances of either light rain or light snow around Monday night through Wednesday of next week. This will be short due to a number of system problems that need to be fixed today, and general work load. The bottom line: outside of very minor tweaks, no changes were made to the forecast. We didn't clear out as early as I thought we would have this morning, but otherwise, things are going as forecast. Sunshine has come out as high pressure from the Dakotas to Texas brings in dry Polar air into our region. With diminishing winds, we'll see higher wind chills today, holding into the 20s...dropping into the teens tonight. But for this time of year, that's typical. Look for winds to go southwesterly tomorrow as the high pushes off to the east, but still allowing for plenty of sunshine. Unfortunately, the winds will become gustier tomorrow afternoon, bringing in slightly milder air, but bringing the wind chills back down to around 20 degrees. Friday, however, is a different story. An Arctic cold front, strongly modified by a lack of snow cover to our north, and that the northeastern U.S. will bear the brunt of it, will nonetheless give us colder temperatures. It should also bring the area some flurries to maybe a dusting of snow as it comes on through, along with gusty north winds. Those winds should set up some sizable lake effect snows over an unfrozen Lake Michigan in far northeastern Illinois and northwestern Indiana later Friday into Saturday. I think the wind fetch will be northerly enough to exclude our eastern campuses, but it will be a very close call. I'll keep watching to see if it hits them, but for now, I'm keeping them snow-free. Stay tuned, as even a slight wind change could bring the lake effect snow bands into DuPage and far northwestern Cook counties later on Friday and Saturday. But for our DeKalb and western campuses, we're dry, sunny but cold this weekend and through at least much of Monday, before a system Monday night into Tuesday, and another on Wednesday come into the area, producing light rain and snow perhaps with the Tuesday system...but Wednesday's system has a better shot of producing accumulating snow. That said, it's one week out, and...well, lots and lots of things can and will go "wrong" between now and then. So, I kept Wednesday as a "chance of snow", and left it at that, as the new GFS model takes that system mostly south of us. My confidence levels on that happening, to reiterate, are not high. After that...there could be another system later next week, but in the changing jet stream pattern is in, I don't want to say anything about it. BUT, the new GFS and European models suggest a wholesale change in the jet stream pattern in the next 1-2 weeks, bringing us more stormy weather than we have seen in the last month. Therefore...look for near average temperatures today and tomorrow...below average Friday-Sunday...and near average much of next week. Precipitation should be very little through Monday morning, and then average to below average, with low confidence, for next week. ******************************************************************************* Gilbert Sebenste ******** (My opinions only!) ****** Staff Meteorologist, Northern Illinois University **** E-mail: sebenste@weather.admin.niu.edu *** web: http://weather.admin.niu.edu ** Twitter: http://www.twitter.com/NIU_Weather ** Facebook: http://www.facebook.com/niu.weather * *******************************************************************************