Convective storms, and their products, thunder, lightning, heavy rains, hail, and tornadoes cause up to $17 billion dollars of damage each year in the United States. The factors influencing this figure include damage to property, deaths and injuries sustained. In addition, these storms cause disruption in farming and industrial activities.
With the frequency of severe storms in the Midwest, and the potential for costly damage to property and possible loss of life, accurately tracking what is happening with the convective climate in the Midwest United States is extremely important.
What is Convective Weather?
Convection is the transfer of heat through a gas or liquid. In meteorology, convection describes the vertical transport of heat and moisture from the Earth’s sun-heated surface into the cooler atmosphere.
As the Earth’s surface heats, it warms the layer of air directly above it. Bare planes, like sand and rocks, heat up quicker than those covered by water and vegetation. This causes pockets of air to heat faster than others. These hot pockets become less dense than the surrounding cooler air. They rise, transporting heat and moisture into the atmosphere. The convection stretches higher into the atmosphere and is stronger in direct correlation with how hot the surface heating is.
Convection causes many weather variations. Generally, the formation of cumulus and cumulonimbus clouds happens when water vapor condenses in the cool upper atmosphere. Convective precipitation is produced once enough droplets are formed. This creates storms with thunder, lightning, and bursts of heavy rain. Convective winds, such as sea breezes, are another common result of weather convection.
Deep, moist convection is a type of instability that is the result of energy released as heat by water changing phases. The instability is ultimately relieved when cold, dry air is pushed downward by the convection process.
In the Tropics, there is an almost constant state of equilibrium in the atmosphere as the convection process stabilizes quickly. In subtropical and temperate zones, the instability can build up over a few days to eventually be released as severe convection.
Severe Convection Storms
Severe convection weather is the assortment of hazardous events, such as large hail, extreme winds, tornadoes and heavy rainfall, produced by deep, moist convection. This is more commonly known as thunderstorms. Although, hazardous weather is produced by non-thundering convection too.
Thunderstorms are confined storms characterized by lightning and thunder. They are also accompanied by an assortment of other phenomena, like heavy rain, hail or snow, high winds, and sudden temperature changes. Thunderstorms need an ample supply of moisture, unstable air, and a source of lift.
Precipitation-producing systems that cause damage, injury and death are termed severe storms. They are significant as they affect the economy, environment, and human health of an area. There are a wide range of severe storm events in the Midwest. Heavy rain, hail, thunder, and lightning in the warmer months; Sleet, snow and ice storms in the colder months.
Severe weather is possible at any time of the year but is most common in the United States during the Spring months of April and May.
Midwestern Climate
The Midwest is located inland, far from any oceans. Consequently, extremes of temperature and precipitation (such Des Moines, IA) occur over differing periods of time. Summers are hot and humid, and winters are cold and snowy. Some possibly hazardous events happen in every season. Severe storms are a fundamental element of the Midwestern climate.
Midwestern climate is influenced by five climatic factors: latitude and solar input, typical positions and movements of weather systems, topography, the Great Lakes, and human activity. The two major influences, affecting the entire region, are the latitude and weather systems.
Solar energy input in the Midwest, is about four times greater in summer than in winter. Combined with the inland location, this causes warm summers and cold winters. The earth’s position relative to the sun affects the amount of solar heating experienced. The wide range of temperatures in the Midwest are indicative of the vast difference in latitude between the northern and southern boundaries. Midwestern latitudinal temperature variances are exhibited by the south’s long summer storm season and more winter storms further north.
The over-all atmospheric circulation is another major influence on the Midwest’s storm development. This large-scale circulation is regulated by the earth’s rotation, variances in solar heating, sea surface temperature, and the position of continents, oceans, and major mountain ranges. Low-pressure storm systems develop due to the polar jet stream passing near or over the Midwest. They are the chief source of the Midwest’s severe storms.
An almost perpetual high-pressure system in the sub-tropical Atlantic, known as the Bermuda High, is another important feature of the general atmospheric circulation. This high-pressure system transports abundant moisture to the Midwest from the Gulf of Mexico and the Atlantic Ocean, causing frequent warm humid days during summer in the southern portions of the United States. This leads to recurrent thunderstorms in the summer. They are more numerous in the southern Midwest than in the northern areas. Areas such as Columbus, Ohio and Indianapolis, Indiana are nearly twice as prone to these storms than places such as Fargo, North Dakota. Spring and fall characteristically have complex weather patterns, causing exceedingly erratic conditions and many convective storms.
With the Midwest being caught between major sources of cold, dry air to the north and west, and warm, moist air to the south, the conditions for generating severe convective storms are ideal.
Of lesser importance, the topographic influences of the various Midwestern hill regions, Great Lakes, and human activity effects on the atmosphere only affect the local climate of their respective areas.
Visual Crossing’s Weather Solutions
The Midwest is located inland, far from any oceans. Consequently, extremes of temperature and precipitation (Des Moines, IA) occur over differing periods of time. Summers are hot and humid, and winters are cold and snowy. Some possibly hazardous events happen in every season. Severe storms are a fundamental element of the Midwestern climate.
Whether you are a farmer wanting to get that next crop in the ground, an architect trying to predict how much longer your client’s new condo will take to build, or event just an avid birdwatcher waiting for the chance to spot the rare American Avocet, Visual Crossing Weather Data is perfect tool to track the optimum weather conditions for your desired activity.
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