Weather prep week: severe thunderstorms

Weather prep week: severe thunderstorms
(Photo Source: WLOX)
What is a severe thunderstorm?
What is a severe thunderstorm?
What is a watch?What is a warning? What is the difference?
What is a watch?What is a warning? What is the difference?

SOUTH MISSISSIPPI (WLOX) - The week of February 19, 2018 has been designated as Severe Weather Preparedness Week in Mississippi. Monday's topic is severe thunderstorms.

The goal of this Severe Weather Preparedness Week is to call attention to severe weather threats and to review severe weather safety rules in an attempt to reduce the loss of life and injury.

What is a Severe Thunderstorm?

A severe thunderstorm is any storm that contains one or more of the following: hail of 1"(quarter size) or larger, winds of 58 miles per hour (50 knots) or greater, or tornadoes.

While severe thunderstorms can occur any time of the year, the most common time for occurrence is during the months of March, April and May.

What is the difference between a watch and a warning?

A watch means that conditions are favorable for severe weather development. Watches are issued for up to six hours. Be aware of rapidly changing weather conditions. And review your severe weather safety plan.

A warning means that severe weather has been detected on radar or has been observed. Warnings are issued for up to an hour. Take cover and activate your severe weather safety plan immediately if under a warning.

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.

The largest hailstone to fall in Mississippi history was 5 inches in diameter, or CD/DVD size. This fell in Lafayette County on April 10, 1962.

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