Weather phrases like “in like a lion, out like a lamb” have floated around the English-speaking world for centuries. But do they have any meteorological base? This is the story of a phrase that is oft-repeated but not necessarily upheld by conditions.
March is a month of seasonal transition. For most of Indiana, it’s still pretty much winter, with occasional flickers of springlike conditions. This is not necessarily true farther south.
In March, the tropics are warming as the sun moves northward and spring approaches. By natural global circulation, that warm air gradually makes its way north, generally accompanied by a low-pressure system.
To the north, arctic air still prevails throughout Canada and the polar region. This cold air is generally associated with high pressure.
In March, these two air masses move closer together, and pressure gradient force takes over.
The laws of atmospheric physics state that wind flows from high pressure to low pressure. This difference of pressure creates the movement of air, which we observe as wind, but due to the impacts of the Coriolis force from Earth’s rotation, and friction from the Earth’s surface, winds usually end up blowing roughly parallel to the pressure gradients.
In March, low- and high-pressure areas are close and winds are increased. The phrase about lions and lambs has been used to describe a stormy start and a calm finish vs. a calm start and a stormy finish, leaving it open to basically any interpretation imaginable. When it comes to forecasting itself, these rhymes and tales can be entertaining, but they’re just that: rhymes and tales. They don’t really do much for forecasting.
Eggert works in the Indiana State Climate office. He writes from West Lafayette, Ind.