How We Decide Rain/Sleet/Snow

Some shoreline locations saw all rain. High elevation towns inland got all snow. Most of us had both plus a little sleet!

Forecasting what kind of slop falls from the sky is one of winter’s most difficult predictions. I wrote a little story about it for Thursday’s Hartford Courant and thought you might enjoy reading along.

We didn’t have a lot of precipitation today, but we sure had a lot of different types! Some shoreline locations saw all rain. High elevation towns inland got all snow. Most of us had both plus a little sleet!

Predicting the precipitation type has everything to do with temperature, though not necessarily the temperature at ground level. Ice crystal formation and snow growth takes place mainly between 10,000 and 20,000 feet up. If the temperature remains below freezing from cloud to ground snow falls intact.

Wednesday had some milder pockets tucked in the atmosphere. Snow melted then refroze producing sleet. Near the shore there wasn’t enough cold air to refreeze the melted snow and so it was rain that hit the ground.

We missed Connecticut’s most dangerous winter precipitation which occurs when mild pockets melt falling snow, but very cold temperatures at the surface refreeze it on contact. Freezing rain can and has turned Interstates to skating rinks!

A Tiny Bit Of Sleet

The snow changed to sleet! Sleet is more dense and has greater survivability. We’re still a long way from accumulating here.

It’s been snowing lightly all afternoon. So far our accumulation is exactly zero. Not unexpected.

Things changed a few minutes ago. The snow changed to sleet! Sleet is more dense and has greater survivability. We’re still a long way from accumulating here. It’s very light.

This will be a small storm, but there to greet you in the morning.