ORLANDO, Fla.- – The short answer, very. Thursday afternoon storms began firing along the east coast sea breeze and exploded as the east and west coast sea breezes collided. Instability, aided by colder temperatures above the surface, was plentiful to fuel the intense hail storms Thursday evening.
The I-4 corridor was especially impacted.
Pictured below were the hail reports 1″ in diameter or larger Thursday evening. The biggest report was 3″ hail or about the size of a tea cup in Sanford. There were several other smaller hail reports across Central Florida. Hail 1″ or great is considered to be severe and a severe thunderstorm warning would be issued by the National Weather Service if a storm was producing or thought-to-be producing hail of that magnitude.
3″ hail ties the record for largest hailstone in the east-central Florida counties that the National Weather Service in Melbourne covers.
How does yesterday's hail event compare to other hail events?— NWS Melbourne (@NWSMelbourne) May 22, 2020
Well, the 3" hail report from Sanford ties the record for the largest hailstone reported in our east central Florida counties, but record for the state of Florida remains 4.5". #flwx pic.twitter.com/yUkTJOdn2M
While Thursday’s hail was huge and exceptionally rare for Florida, the record for the Sunshine State still stands at 4.5″. This grapefruit-size hail has been observed on three occasions in Florida; in Polk county in March of 1996, Bradford county in March of 2003 and in Marion County on May 13 2007.
It is even more uncommon for large hail in Florida because it is much warmer in this part of the world at ground level and in the upper atmosphere. Notice the months, however, for the record hail events in Florida. Most big hail occurs in late winter or spring in Florida when it is typically cooler, especially above the surface. It was in the mid 90s at the ground, but about 14 degrees 18,000 feet above the surface Thursday.
How does hail form?
Thunderstorms are made up of updrafts and downdrafts. The updraft is the rising air within the thunderstorm and the downdraft is the downward moving air, eventually producing the gusty winds we feel on the ground and damage if strong enough.
Hail forms in thunderstorms with intense updrafts. The updraft forces rain high into the thunderstorm where the air is below freezing. The rain drops freeze becoming ice.
If the updraft is strong enough, the newly-formed hailstone cycles through the storm and grows. The hailstone forms layers by colliding with water and supercooled water, water that remains in the liquid state even though temperatures are below freezing.
Once the hailstone becomes too heavy to be supported by the thunderstorm updraft, it falls to the ground. The more intense the thunderstorm updraft, the larger the hail typically is. Oftentimes, hail can look like onions with multiple layers. This is more evident if you cut the stone in half.
When looking at the clear sections, the air was below freezing, but not extremely cold. The water spreads out over the stone and slowly freezes. Air bubbles are allowed to escape making the ice clear.
When the ice is cloudy, the air temperature where the ice formed is well below freezing, oftentimes locking in air bubbles because the water froze so fast. This leaves the ice more cloudy.
If you count the number of cloudy and clear rings/layers, you can estimate how many trips the stone made within the thunderstorm!
Making Thursday night’s hail even more impressive was the fact that temperatures at ground level were in the 90s, so melting of the hail likely took place before it reached the ground!
Most of the reports from Orange, Seminole and Osceola counties Thursday evening were the size of golf or ping pong balls, making this event all the more noteworthy. Hailstones Friday were also big, but nowhere near the size of the giant hail that fell Thursday night.