Frosty Wednesday morning, Toasty Wednesday afternoon


After temperatures Wednesday morning dropped into the mid and upper teens, sunny skies prevailed for much of the afternoon. The combination of sunshine and a very dry atmosphere allowed temperatures to warm quickly late morning, all the way into the mid and upper 40s by the afternoon. Officially, Rockford reached 49 degrees. The 30 degree temperature rise was quite impressive given the time of year and low the sun angle is in the sky.

There were a couple of factors that lead to the rapid jump in temperatures Wednesday – mostly sunny skies, dry soil and a dry air mass. In fact, the dry air mass is likely the main reason why we felt temperatures warm so much. Dew point temperatures – a direct measure of moisture in the atmosphere – Wednesday across much of the Stateline were in the teens and low 20s. The drier the air mass, the more efficient it is to warm. That’s because the air molecules in the atmosphere are able to move more freely, allowing the warm up to happen faster.

An air mass that has more water vapor molecules (moisture) doesn’t allow the air molecules to move around as much, slowing the warming process. That’s why on days when the dew point temperatures are higher, the temperature spread from morning to afternoon typically isn’t as great.

Dew point temperatures these next few days will remain low, but we will see the numbers rise Thursday and Friday. It won’t be enough to bring us any precipitation as the lower portions of the atmosphere remain dry, but just enough to add in a few more clouds throughout the day.

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