Mississippi Severe weather Awareness Week Day 1: Severe Thunderstorms

Mississippi Severe weather Awareness Week Day 1: Severe Thunderstorms
(Photo source: WDAM First Alert Weather Team)

PINE BELT (WDAM) - While only a fraction of all thunderstorms are severe, those are the storms people tend to remember the most. A storm is "severe" when it produces hail larger than the size of a quarter, wind gusting more than 58 m.p.h or has the potential to produce a tornado.

So what is the difference between a Severe Thunderstorm Watch and a Severe Thunderstorm Warning?

A Severe Thunderstorm WATCH means that conditions are favorable for the development - a bit later - of severe thunderstorms. A "Particularly Dangerous Situation" (PDS) WATCH means conditions are favorable for development of intense severe weather. A WATCH usually lasts between four and eight hours.

A Severe Thunderstorm WARNING means that a storm is severe right now, it is moving toward your location, and will be there soon. It is important to take action and get indoors. A WARNING usually lasts less than one hour.

The National Weather Service in Jackson, Mississippi explains the two biggest threats with severe thunderstorms in detail as:

Damaging Winds

Damaging thunderstorm winds are common across Mississippi any time of the year. Damaging winds (sometimes referred to as straight-line winds) can do just as much, if not more, damage than a tornado. These storms can knock down trees and cause damage to structures. While these winds can occur any time of year, damaging wind reports tend to increase during the spring months and peak during the summer months in Mississippi. In mid June 2012, a large complex of thunderstorms moved across the state from the northwest. This complex of storms brought widespread tree and power line damage with 60 to 70 mph wind gusts. Some pockets of significant wind damage occurred in the Mississippi Delta where winds likely gusted around 80 mph.

Severe Hail

Hail is formed when water droplets are drawn into an area of strong upward moving air, known as an updraft, of a storm. Once the water droplets are transported above the freezing level, they combine with tiny airborne particles, such as dirt, salt, etc., and freeze on contact, forming tiny ice particles. These ice particles are light enough that they remain suspended in the cloud, where they undergo processes that allow them to combine with other supercooled water droplets and grow into hailstones. Once the hailstones are heavy enough to overcome the upward force of the updraft, they fall out of the cloud.

Hail can occur throughout the year as long as temperatures aloft are cold enough to support freezing of the hailstone, and won't melt the hail as it falls. The spring months tend to be the time of year that the largest number of severe hail reports occur. In addition, the highest number of large hail (2 inches or larger) reports also occurs during the spring months.

Large hail can cause significant damage to crops and property. On March 18, 2013, hail to the size of ping pong balls, tennis balls and even softballs fell across several locations in central Mississippi. The largest of the hailstones fell across portions of the Jackson metro area during rush hour. This caused significant damage to thousands of cars and many buildings. Around 550 million dollars in damage was caused by this destructive hailstorm. The softball size hailstone that fell in Clinton, MS was the third largest hailstone to fall in March in Mississippi since 1950 and the seventh largest to fall in the state for any month of the year.

This is why when a Severe Thunderstorm Warning is issued, we urge folks to get inside and away from the weather.