It has been a very warm December so far, compared to where temperatures should be this time of year. We saw above average temperatures 17 of the first 19 days of December, with a number of days with highs in the 30s and 40s. Our normal high temperature so far this month is 32 degrees, well above our average high temperature for this timeframe of about 25 degrees. But that is all about to change.
According to the Climate Prediction Center, the last week of the year has an 80% probability of having below normal temperature, and the first week of 2018 has a 70% probability of having below normal temperatures. With probabilities of below average temperatures this high, we expect very frigid air to filter in during this timeframe. Forecast models show that for some days over the next two weeks, high temperatures across the region could be 0 to as low as -10. Overnight low temperatures across the area could get down into the -20s and -30s. Average high temperatures during this timeframe are around 19, with lows typically near 2.
As we deal with the coldest air of the year, one bit of good news is that there is a significantly lower chance of having any big snowstorms. The last week of the year, we have a 40% chance of seeing below normal precipitation; the first week of 2018 gives us a 33% chance of below normal precipitation. Over the next couple of weeks, we will mainly
see partly to mostly cloudy skies, with occasional snow showers that don't amount to much.
Outlooks show we should start to see moderating temperatures and will be back to average levels of precipitation as we approach mid-January. There might be another couple of cold snaps through the winter, but outlooks show we will probably end the winter season with temperatures averaging out to above normal levels.