The high temperature on Saturday was 57°F (14°C), yet today’s high will be below 20°F (-7°C)!
There is a large, deep area of high pressure to our west (over the Great Lakes). Because we live on a rotating planet, air flows clockwise around high pressure systems. Therefore, today’s airflow is predominantly from the north. Air advecting from the north tends to be cold, since it is coming from the Arctic region.
High pressure also leads to a clear sky. In a high, air is “subsiding,” or sinking, towards the ground. Due to adiabatic heating, cloud droplets are evaporated very quickly. We can also expect a very windy day. Wind speed is, in part, determined by the gradient of the isolines of pressure (isobars). When the isobars are very close, as in today’s situation, wind speeds are high.
Luckily for us (unless you enjoy the cold), the high pressure will rapidly move eastward over the next day. Tomorrow’s high temperature should be about 10 degrees warmer than today, as the northerly winds die down and there is less cold air advection.
Today: Bitterly cold, windy, and sunny. High 17°F (-8°C).
Tonight: Bitterly cold, windy, and clear. Low 8°F (-13°C).
Tomorrow: Some clouds. High 26°F (-3°C).
Tomorrow night: Some clouds. Low 14°F (-10°C).
Thursday: A few clouds. High 26°F (-3°C).
Thursday night: Clear. Low 17°F (-8°C).