How can hail fall when it is above freezing?

Hail can fall and even accumulate on the ground when the air temperatures is well above freezing! Why is this?

Hail is formed in many layers within the sub-freezing tops of thunderstorms. In fact, a hailstone is formed in many layers. Therefore, when the hail speeds toward the ground through the progressively warmer layers of atmosphere, some of the outer layers of the hail may melt, but many layers still remain.

Whatever is left of the hail, which can still be quite a bit (as seen in the photo), then lands and remains on the ground until the rest of the hailstone can melt away on the surface.

Jonathan Myers

What the "hail" was that?

A pocket of cold air aloft combined with an upper air disturbance, kicked off a few exciting thunderstorms on Thursday afternoon. This time it wasn't wind that caused major problems, it was hail! Why hail forms has everything to do with how low the freezing line is in a thunderstorm.

The hail nucleus, buoyed by the updraft is carried aloft by the updraft and begins to grow in size as it collides with supercooler raindrops and other small pieces of hail. Sometimes the hailstone is blown out of the main updraft and begins to falls to the earth. If the updraft is strong enough it will move the hailstone back into the cloud where it once again collides with water and hail and grows.

This process may be repeated several time. In any case, when the hailstone can no longer be supported by the updraft it falls to the earth. The stronger the updraft, the larger the hailstones that can be produced by the thunderstorm.

Image Courtesy of www.srh.noaa.gov

What is all of this white on the satellite?

The visible satellite, shown here, basically takes a "photo" of the clouds. These, in fact, are some high cloud tops associated with a batch of severe thunderstorms over the Western Southern Tier of New York. These thunderstorms produced damaging wind and heavy rain across Western New York.

Note: The whiter the clouds, the higher the tops, the gray clouds represent lower clouds.

Jonathan Myers

Some Fiesty Storms Tuesday Afternoon

Plenty of heat and humidity will help develop thunderstorms during Tuesday afternoon. In scenarios like this we look at several parameters to determine if storms may become severe. One of the more important variables is Convective Available Potential Energy (CAPE). This is the maximum amount of energy available to an ascending parcel of air.

The higher the value, the greater the instability. Once values reach over 1,500 J/KG (Joules per kilogram), strong thunderstorms are possible. On Tuesday afternoon, we expect CAPE to reach near 2,000 J/KG. Some storms may have wind gusts near 60 mph and small to moderate sized hail. Stay tuned to News 8 for the latest on the storms Tuesday afternoon and evening.