(WBRE/WYOU-TV) — When it comes to winter precipitation, we can quickly go from snow to ice or rain to snow, but why exactly is that? Meteorologist Logan Westrope explains why.
Tis’ the season for not only rain but snow, sleet, and freezing rain. When it comes to forecasting which type of wintry precipitation an area may see, it’s important to remember where it all starts…in the clouds.
“In winter, especially over the mid-latitudes, places like Pennsylvania, the truth is most precipitation actually begins in the cloud, as a snowflake,” said Dr. Jon Nese, Penn State Meteorology professor.
That snowflake can encounter a long, ever so-changing journey from the cloud to the ground. During the winter is when we typically have more of that battleground between colder and warmer air. Now, everything starts as a snowflake up near the cloud, but then once you have those pockets of warmer air, that’s when we start to see some of those changes in the winter precipitation.
For snow to form, we start with that snow all the way from the cloud and it makes it all the way down to the surface, still staying as snow. Now, if you add a little bit more of a pocket of warmer air in the upper levels of the atmosphere, that’s when we see those snowflakes turning from snow into sleet pellets.
Adding a little bit warmer air into the mix, that’s when we have snowflakes turning into raindrops. But, right at the ground, is where we are still at or below freezing, so that’s when we have freezing rain. When you have all warm air from the surface to the cloud, that’s when we have all plain rain.
A big misconception Dr.Nese says during the winter months is the difference between sleet and hail.
“Hail is strictly a thunderstorm phenomenon, which means it occurs mainly in the warm season when thunderstorms are more plentiful. Sleet, on the other hand, very specifically refers to a melted snowflake, or partially melted snowflake, that falls through a layer of the atmosphere that’s cold enough to turn that partially melted snowflake, or even raindrop into a little pellet of ice,” explained Dr. Nese
As for the worst type of precipitation to drive in… Especially with no traction: “Not with your shoes, not with your tires. So freezing rain, by far, is most dangerous,” said Dr. Nece.