Tomorrow is forecast to be nearly the same temperature as today.
Nowcast as of 3:42 PM CST on December 8, 2009
Now
Precipitation is expected to continue to overspread the area late this afternoon and evening. Precipitation is expected to begin as all snow...and continue to fall as snow through the early evening hours. This snow may begin to mix with sleet and or rain late this evening and overnight...especially across areas close to Interstate 88. Where rain and sleet mix with the snow...snow accumulations are expected to be between 4 and 6 inches. The best chance for precipitation remaining all snow appears to be across central and western portions of Winnebago...Lee..and Ogle counties...where snow accumulations could be as high as 10 to 12 inches.
Forecast for McHenry
Updated: 3:48 PM CST on December 8, 2009
Winter Storm Warning in effect until 6 PM CST Wednesday...
Tonight
Snow or rain or sleet or slight chance of thunderstorms until early morning...then rain or snow or slight chance of thunderstorms during the predawn hours. Precipitation may be heavy at times. Snow and sleet accumulation of 3 to 6 inches. Blustery. Temperatures nearly steady in the lower 30s. East winds 15 to 25 mph with gusts up to 35 mph at times until early morning decreasing to 10 to 15 mph during the predawn hours. Chance of precipitation 100 percent.
Wednesday
Windy...cloudy. Snow in the morning...then a chance of light snow in the afternoon. Blowing snow in the late morning and afternoon. Snow accumulation of 1 to 2 inches. Total snow accumulation 4 to 9 inches. Turning sharply colder. Highs in the lower 30s. Then temperatures falling into the upper teens by evening. West winds around 10 mph early in the morning increasing to 20 to 30 mph with gusts up to 40 mph at times in the late morning and afternoon. Chance of precipitation 90 percent.
Mostly cloudy. Areas of blowing snow in the evening. Blustery. Much colder. Lows 3 below to 1 above zero. Lowest wind chill readings 15 below to 25 below zero after midnight. West winds 15 to 25 mph. Gusts up to 40 mph in the evening decreasing to 30 mph after midnight.
Thursday
Mostly sunny. Very cold. Highs 7 to 11 above. Lowest wind chill readings 20 below to 30 below zero in the morning. West winds 10 to 20 mph with gusts up to 30 mph at times.
... Winter Storm Warning remains in effect until 6 PM CST Wednesday...
A Winter Storm Warning remains in effect until 6 PM CST Wednesday.
* Timing: periodic snow this afternoon will increase in intensity and coverage early this evening. Snow will begin to mix with or change to sleet and then rain this evening into the overnight hours. Precipitation will change back to all snow very late tonight into early Wednesday morning with some additional accumulation expected very late tonight during Wednesday.
* Accumulations: snowfall accumulations through this evening of 4 to 8 inches are likely before precipitation changes to rain tonight. Once precipitation changes to back to snow late tonight into Wednesday an additional 1 to 3 inches of snow is possible. Snowfall accumulations will be highly dependent on precipitation type... which can vary with just a 1 degree change in temperature. Should temperatures warm faster this evening then snow accumulations could be dramatically less.
* Misc hazards: strong easterly winds... possibly gusting over 40 mph... are expected this evening resulting in considerable blowing snow. Strong west winds will develop during the day Wednesday... which if the snowfall late tonight and Wednesday is fluffy enough... could result in severe blowing and drifting snow and near ground blizzard conditions in open areas.
* Impacts: travel conditions will likely deteriorate rapidly late this afternoon and evening... with most roads becoming snow covered Tuesday evening. Drifting snow may be a particular problem... especially along north to south routes on Wednesday.
Precautionary/preparedness actions...
A Winter Storm Warning for heavy snow is issued when 6 or more inches of snow is forecast to occur. The heavy snow will make travel dangerous. If you must travel... keep a flashlight... food... and water in your vehicle in case of an emergency.