Most of us like popcorn, but what is a popcorn shower? This is not an official meteorological term, but I like to use it when hit and miss showers pop-up on the radar screen. When we have “popcorn” showers or storms most people will be dry. However, if you end up under one of these showers or storms it can ruin your outdoor plans. One of our big challenges as meteorologists is how to word our forecasts when we have hit and miss showers. I don’t like to go on the air and just say we have a “chance” of showers. I try to give everyone a little more information. I will usually try to expand on the forecast by saying most places will remain dry, but have your umbrella handy. Furthermore, I will tell you not to cancel your outdoor plans. Take a look at the radar from 3:30 on Sunday afternoon.
Notice that the majority of SE Wisconsin is dry. There are a few showers in Dodge, Fond du Lac, Washington, and Ozaukee counties. “Popcorn” showers and storms can bring brief heavy downpours and are created in the afternoon after the heat of the sun causes the air to rise and cumulus clouds begin to form. These cumulus clouds can merge and grow rapidly in colder air aloft. Cold air aloft brings instability, meaning that rising motion is not inhibited once a parcel of air is lifted. The lifting today came from the sunshine warming the surface. The satellite map can often show the “popcorn” showers as well.
Note the dots of clouds across central and NE Wisconsin. These are the fair weather cumulus clouds with no rain. In SE Wisconsin, some of the cumulus clouds have turned into cumulus congestus clouds with scattered showers. The nice thing about “popcorn” showers and storms is that they do not last long. They pop-up and then dissipate pretty rapidly.
Tomorrow our afternoon weather will bring another chance of “popcorn” showers, but again, don’t change your outdoor plans. Thanks for reading.