Everyone knew it wouldn't last.

And sure enough, the mild weather this January, traditionally the coldest month of the year, has abruptly ended.

It ended late Wednesday afternoon when brisk, northerly winds ahead of an "Alberta Clipper" cold wave sent the wind chill here plunging to minus 30 and minus 40 degrees by dusk.

On Thursday, Cape Girardeau area residents woke up to the coldest day so far this season. The official low at the airport was 10 degrees, making it the coldest morning here since Nov. 9, 1991, when the temperature fell to 12 degrees.

The National Weather Service said warmer temperatures are expected to return by early next week. And the weather service's 30-day outlook calls for continued seasonal temperatures and below average precipitation.

Despite the sudden change, Al Robertson, professor of earth science and climatologist at Southeast Missouri State University, said Thursday's morning low wasn't even close to the record low for the Jan. 16. It's minus 12 degrees, set in 1982.

The record low for Jan. 17 is minus 16 degrees, set in 1977.

Robertson said the period from mid-January to mid-February is traditionally the coldest time of the year in the Cape Girardeau area. From Jan. 21 to Jan. 31, the long-term average temperature will be at the lowest level of the year, 33.2 degrees. After Feb. 1, the average begins to rise until it peaks at 75.4 degrees between July 11 and 20.

Robertson said local, 46-year weather records indicate that during the period Jan. 7 to Feb. 3, there are only two days when the daily record low temperature is at or above zero.

The all-time record low at the airport occurred Jan. 11, 1977, when the temperature dropped to minus 18 degrees. Other noteworthy record lows this month include: minus 15 degrees on Jan. 20, 1985; minus 14 degrees on Jan. 23 and 24, 1963, and minus 12 degrees on Jan. 28, 1961.

Despite the normally cold temperatures, it does get unusually warm, even at this time of the year. Record highs at the airport during January include 73 degrees on Jan. 23, 1967, and Jan. 24, 1950. However, most of the other record highs that occurred during the month were in the 60s.

Robertson said mild weather during the first half of the month resulted in an average temperature for the period of 38.8 degrees, up 6.4 degrees from the long-term average of 32.4. Daytime highs during the period were some 5 to 10 degrees above normal while overnight lows were almost as warm.

Precipitation during the first half of January totaled 2.27 inches, including 2 inches of snow on Jan. 13-14.