What is the synoptic/atmospheric setup that is causing the U.S. severe weather outbreak in May 2019?

The Synoptic/Atmospheric Setup Causing the U.S. Severe Weather Outbreak in May 2019

1. Introduction.

In May 2019, the United States experienced a widespread and significant outbreak of severe weather events, including tornadoes, damaging winds, and large hail. This outbreak captured the attention of meteorologists and the public alike due to its intensity and large-scale impacts on the affected areas. Understanding the synoptic and atmospheric setup that led to this severe weather outbreak is critical to improving our forecasting capabilities and our understanding of severe weather patterns. In this article, we will examine the synoptic and atmospheric conditions that contributed to the May 2019 severe weather outbreak in the United States.

2. Synoptic Setup

The synoptic setup during the May 2019 severe weather outbreak was characterized by a dynamic and strong weather pattern across the United States. A key feature was the presence of a strong and slow-moving upper-level trough, also known as a negatively inclined trough, that extended across the central and eastern portions of the country. This trough acted as a catalyst for the development and intensification of severe weather systems.

The negatively tilted trough provided favorable conditions for the formation of a deep and strong surface low-pressure system. This trough served as a focal point for the convergence of warm, moist air from the Gulf of Mexico and cool, dry air from the north. The clash of these contrasting air masses created an environment ripe for severe thunderstorm development and subsequent tornado formation.

3. Atmospheric Setup

The atmospheric setup during the May 2019 severe weather outbreak was characterized by a combination of instability, moisture, and wind shear. Instability refers to the potential energy available in the atmosphere for thunderstorm development, while moisture provides the necessary fuel for storm development. Wind shear, on the other hand, refers to the change in wind speed and direction with height and plays a critical role in the organization and maintenance of severe thunderstorms.

During this outbreak, a warm and moist air mass from the Gulf of Mexico was advected northward, resulting in an influx of high moisture into the affected regions. This moisture, combined with the unstable conditions provided by the synoptic setup, created an environment conducive to the development of severe thunderstorms.

In addition, the presence of strong wind shear increased the potential for storm organization and rotation. Wind shear helps to separate the updraft and downdraft regions within a thunderstorm, allowing for the development of rotating updrafts, or mesocyclones. These mesocyclones are often precursors to tornado formation, and were a prominent feature during the May 2019 severe weather outbreak.

4. Contributing Factors

Several factors played a role in the severity and extent of the May 2019 severe weather outbreak in the United States. One important factor was the availability of ample moisture from the Gulf of Mexico, which provided the necessary fuel for thunderstorm development. The warm and moist air mass acted as a source of instability, allowing for the rapid growth and intensification of severe thunderstorms.

Another contributing factor was the slow movement of the upper level trough and associated surface trough. The slow progression of these features allowed for prolonged periods of severe weather, increasing the overall impact and duration of the outbreak.

In addition, the presence of a strong low-level jet stream, characterized by fast and directed winds, contributed to the development of rotating updrafts and the subsequent formation of tornadoes. The interaction between the low-level jet stream and the synoptic and atmospheric conditions provided the necessary ingredients for tornado formation and contributed to the widespread nature of the outbreak.
In conclusion, the May 2019 severe weather outbreak in the United States was the result of a complex synoptic and atmospheric setup. The combination of a negatively tilted trough, converging air masses, instability, moisture, and wind shear created an environment highly conducive to the development of severe thunderstorms and tornadoes. Understanding these synoptic and atmospheric factors is critical to improving severe weather forecasting and our ability to mitigate the impacts of future severe weather events.

FAQs

What is the synoptic/atmospheric setup that is causing the U.S. severe weather outbreak in May 2019?

The severe weather outbreak in May 2019 in the United States was primarily attributed to a combination of synoptic and atmospheric factors. The key setup involved the interaction between a strong low-pressure system, a warm and moist air mass, and a dynamic jet stream pattern.

How did the strong low-pressure system contribute to the severe weather outbreak?

The strong low-pressure system acted as a catalyst for the severe weather outbreak. It provided the necessary lifting mechanism to initiate the formation of thunderstorms. The presence of a deep low-pressure system allowed for the upward movement of warm, moist air, leading to the development of strong updrafts and the potential for severe thunderstorm activity.

What role did the warm and moist air mass play in the severe weather outbreak?

The warm and moist air mass played a crucial role in fueling the severe weather outbreak. Moisture-rich air from the Gulf of Mexico was transported northward, providing a significant source of instability and moisture for the formation of thunderstorms. The warm air also contributed to the steep lapse rates, creating an environment conducive to the development of severe thunderstorms.

How did the dynamic jet stream pattern impact the severe weather outbreak?

The dynamic jet stream pattern played a vital role in the severe weather outbreak. An amplified jet stream pattern, with a trough and ridge configuration, created favorable conditions for the development of severe thunderstorms. The trough allowed for the transport of energy and moisture from the Gulf of Mexico, while the ridge provided an area of enhanced wind shear, which is essential for the organization and intensification of thunderstorms.

Were there any other contributing factors to the severe weather outbreak in May 2019?

While the primary synoptic and atmospheric setup described above were the main contributors to the severe weather outbreak, other factors could have played a role as well. These may include local topographic features, such as mountains or bodies of water, which can influence the initiation and organization of thunderstorms. Additionally, mesoscale convective systems (MCSs) and the associated outflow boundaries can also contribute to the development and intensification of severe weather events.