Uncertainty over where freezing rain and snow might fall still lingers as the thermometer gets set to drop Thursday to the season’s lowest levels yet. But just to be on the right side of caution, Cullman County Schools made the call late Wednesday to postpone Thursday’s school day start.

A final decision about the full day of classes, as well as Friday’s, is expected early Thursday morning. But as of late Wednesday, school buses were set to run this morning on a two-hour delay, with students asked to show up for Thursday classes at 10 a.m.

With timelines and affected areas still in question late Wednesday, the Huntsville office of the National Weather Service issued a Winter Weather Advisory effective until 6 p.m. Thursday that includes all of Cullman County.

Affecting all of the Huntsville office’s coverage counties in north Alabama and southern Tennessee, the advisory anticipates mixed winter precipitation through the Thursday, as well as rain possibly changing to freezing rain or snow as temperatures fall farther to the south in Cullman and neighboring counties.

Beginning in west Alabama and progressing eastward, wintry precipitation “will start out as a mix of freezing rain, sleet & snow north of the Tennessee River, while south of the river, more of a rain & freezing rain mixture is expected,” NWS advises.

In locations where temperatures fall far enough through the afternoon hours, a transition from rain to freezing rain, sleet, and snow is expected to arrive during the day Thursday. Snowfall accumulations north of the Tennessee River were forecast to reach 1 inch, while freezing rain in Cullman and other southerly counties was also expected to accumulate up to one-tenth of an inch of surface ice. NWS cautioned, though, that area forecasts could change as the system nears, and urge residents to remain alert to the most recent updates.

While some of Thursday’s local precipitation may arrive during the warmer hours as rain, residual moisture is expected to linger into the evening, when temperatures in Cullman County will take a dramatic dive into the teens. The front that comes in on the back of Thursday’s wet weather will bring “dangerous cold,” according to NWS, with temperatures in Cullman and other area counties sinking to between 10 and 18 degrees. Winds of 15 mph will make outdoor conditions even harsher; forecasters expect wind chill measurements overnight of between 2 and 10 degrees.

NWS cautions that local motorists should plan to encounter slippery road conditions after night falls Thursday, with black ice and other ice-related hazards also potentially affecting Friday morning’s commute.