Pulse? Supercell? Not All Thunderstorms The Same
More than 100,000 thunderstorms hit the United States annually,but did you know there are different types?
Let's step into a little meteorology 101 and take a look at a few of the ones you might hear meteorologists talk about,and who knows,maybe it'll come in handy for a trivia night,or at the very least you can impress your friends.
Supercell
This is the king of all thunderstorms and they are often accompanied by dangerous weather conditions,including large hail,damaging winds and,sometimes,tornadoes.
Supercell thunderstorms can last several hours and track hundreds of miles. They often have a distinct appearance on radar,with a on the southwest corner of the storm (lower left below) which sometimes indicates a tornado is in progress. To the north and northeast of that hook is the storm's main cell where huge hail,high winds and heavy rain can occur.
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When viewed in an open area,classic supercells have a "mothership"appearance often photographed in the Plains states. Most large and violent tornadoes are spawned by supercells.
They develop in volatile severe weather setups that contain plenty of wind shear. This change in wind speed and direction with height in the atmosphere keeps the storm's downdraft separated from its updraft,allowing it to grow and sustain itself for long periods of time.
(MORE:Everything To Know About Supercells)
Squall Line
Also known as a multi-cell line,this type of thunderstorm can pack widespread damaging winds as well as an embedded tornado threat.
As the name implies,squall lines are thunderstorms arranged in a line,often from north to south. They can be hundreds of miles long but are usually only about 10 to 20 miles wide. An extreme form of a squall line that meets a certain longevity threshold is called a derecho.
In addition to the threat of high winds and tornadoes,squall lines contain blinding rain and frequent lightning as well.
Within a squall line is often one or more,which can produce bursts of stronger winds in concentrated areas.
Pulse Thunderstorm
These storms can rapidly form and then fall apart just as quickly.
They are sometimes also called pop-up thunderstorms,popcorn thunderstorms or air mass thunderstorms. We see them commonly pulse up with daytime heating in summer,especially in the South.
Pulse thunderstorms generally last less than an hour and can occasionally turn severe with strong wind gusts being the primary threat,but they also pack torrential downpours and frequent lightning.
These storms form when the sun heats humid air and causes it to rise,cool and condense,allowing a cumulonimbus thunderstorm cloud to form.
Since there is often little wind shear in the atmosphere where these storms form,they don't last very long. That's because the lighter winds in upper atmosphere cause the storm's downdraft to be located too close to the updraft. This results in the inflow of upward-rising air that fuels thunderstorms to get choked off by the rain and hail-laden downdraft.
Multi-Cell Cluster
These clusters of thunderstorms are commonly seen year-round and can last several hours,though they are most common in warmer times of the year.
Within the larger cluster are multiple individual thunderstorm cells that last 30 to 60 minutes,according to NOAA. The outflow from each cell helps form what's called a gust front,where converging winds cause new cells to develop,allowing the cluster to persist.
Severe weather can occur in multi-cell storms with hail,strong winds and sometimes brief tornadoes being threats.
They can also be prolific rainfall producers that cause flooding when additional cells form on the upwind side of the cluster and then "train"heavy rain over an area already soaked by a previous cell or cells.
Chris Dolce has been a senior digital meteorologist with www.weathernow24.com for nearly 15 years after beginning his career with Weather Now 24 in the early 2000s.
