Tropical Storm Bertha was a rapidly forming and short-lived off-season tropical storm that affected the

Eastern United States The Eastern United States, commonly referred to as the American East, Eastern America, or simply the East, is the region of the United States to the east of the Mississippi River. In some cases the term may refer to a smaller area or the East C ...

in late May 2020. The second

named storm Tropical cyclones and subtropical cyclones are named by various warning centers to simplify communication between forecasters and the general public regarding forecasts, watches and warnings. The names are intended to reduce confusion in the ...

of the very active

2020 Atlantic hurricane season The 2020 Atlantic hurricane season featured a total of 31 tropical or subtropical cyclones, making it the most active Atlantic hurricane season on record. All but one cyclone became a named storm. Of the 30 named storms, 14 deve ...

, Bertha originated from a trough in the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United ...

. The National Hurricane Center (NHC) only anticipated slight development as the trough moved over southern

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, bringing torrential rainfall. The system rapidly organized on May 27 after it emerged into the western

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

, developing a small, well-defined circulation. That day, the disturbance developed into Tropical Storm Bertha east of

Georgia Georgia most commonly refers to: * Georgia (country), a country in the Caucasus region of Eurasia * Georgia (U.S. state), a state in the Southeast United States Georgia may also refer to: Places Historical states and entities * Related to the ...

, and a few hours later it moved ashore near

Isle of Palms, South Carolina Isle of Palms is a city in Charleston County, South Carolina, United States. At the 2010 census, the population was 4,133. Isle of Palms is a barrier island on the South Carolina coast. The city is included within the Charleston-North Charleston ...

with peak winds of . The storm weakened over land and dissipated late on May 28 over

West Virginia West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the B ...

. The storm and its precursor disturbance caused heavy rainfall and flash flooding in southern Florida, as well as spawning a brief

tornado A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...

. In South Carolina, Bertha produced above normal tides and locally heavy rainfall, causing minor flooding. As the storm moved into

North Carolina North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and ...

, its remnants produced a brief

, while

rip current A rip current, often simply called a rip (or misleadingly a ''rip tide''), is a specific kind of water current that can occur near beaches with breaking waves. A rip is a strong, localized, and narrow current of water which moves directly away ...

s resulted in several water rescues in Surf City. According to the National Centers for Environmental Information, Bertha caused $130,000 (2020

USD The United States dollar (symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the official ...

) in damage.

Meteorological history

A trough, or elongated

low pressure area In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. Low-pressure areas are commonly associated with inclement weather (such as cloudy, windy, with possible ...

, developed in the southeastern Gulf of Mexico on May 24. By that time, the trough extended across southern Florida into the western Atlantic Ocean, producing a widespread area of thunderstorms. The National Hurricane Center (NHC) first mentioned the system in a special tropical weather outlook on May 25, assessing a 20% chance for tropical

cyclogenesis Cyclogenesis is the development or strengthening of cyclonic circulation in the atmosphere (a low-pressure area). Cyclogenesis is an umbrella term for at least three different processes, all of which result in the development of some sort of cycl ...

, due to expected strong

wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizont ...

, the proximity to land, and dry air. By that time, the trough extended across southern Florida into the western Atlantic Ocean, producing a widespread area of thunderstorms. A weak surface low formed near Orlando, Florida early on May 26, which moved northeast over water by early the following day. Subsequently, the NHC increased the system's development potential to 30%. Early on May 27, the system developed a well-defined center underneath an area of organized

thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are some ...

s. In addition, an offshore buoy recorded tropical storm-force winds. The NHC estimated that the system developed into Tropical Storm Bertha at 06:00 UTC that day while located about east of

Savannah, Georgia Savannah ( ) is the oldest city in the U.S. state of Georgia and is the county seat of Chatham County. Established in 1733 on the Savannah River, the city of Savannah became the British colonial capital of the Province of Georgia and later t ...

. Operationally, it was not until 12:30 UTC that the NHC had initiated advisories on Bertha. The storm had characteristics of both a

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

and a

subtropical cyclone A subtropical cyclone is a weather system that has some characteristics of both tropical and an extratropical cyclone. As early as the 1950s, meteorologists were uncertain whether they should be characterized as tropical or extratropical cyclon ...

, but the NHC designated it as tropical due to the storm's small

radius of maximum wind The radius of maximum wind (RMW) is the distance between the center of a cyclone and its band of strongest winds. It is a parameter in atmospheric dynamics and tropical cyclone forecasting. The highest rainfall rates occur near the RMW of tropic ...

s. Upon its formation, Bertha was moving northwestward around the western side of a ridge over the western Atlantic. At 12:00 UTC, the storm had reached peak winds of ; this was based on observations from buoys and the storm's well-defined curved

rainband A rainband is a cloud and precipitation structure associated with an area of rainfall which is significantly elongated. Rainbands can be stratiform or convective, and are generated by differences in temperature. When noted on weather radar im ...

s near the center. Its gale-force winds extended only from the center. At 13:00 UTC on May 27, 2020, Bertha made

landfall Landfall is the event of a storm moving over land after being over water. More broadly, and in relation to human travel, it refers to 'the first land that is reached or seen at the end of a journey across the sea or through the air, or the fact ...

near

while at peak intensity. The storm quickly weakened as it progressed inland, falling to tropical depression status within a few hours of moving ashore. The depression turned toward the north, moving through western North Carolina and into western Virginia. Early on May 28, Bertha transitioned into an extratropical cyclone, which persisted another 12 hours before dissipating over northern West Virginia.

Preparations and impact

Florida

The precursor disturbance to Tropical Storm Bertha caused a significant, multi-day rainfall event across South Florida, reaching across several locations. The peak 72–hour accumulation was , recorded in

Miami Miami ( ), officially the City of Miami, known as "the 305", "The Magic City", and "Gateway to the Americas", is a coastal metropolis and the county seat of Miami-Dade County in South Florida, United States. With a population of 442,241 at ...

. Rainfall rates of an hour contributed to a 24-hour total of there, more than doubling the previous daily rainfall record and resulting in the city's most significant rain event in eight years. The precursor disturbance spawned an EF1 tornado in Aladdin City, which produced winds of and was on the ground for . The tornado damaged trees and fences, and overturned several campers. There was also a

funnel cloud A funnel cloud is a funnel-shaped cloud of condensed water droplets, associated with a rotating column of wind and extending from the base of a cloud (usually a cumulonimbus or towering cumulus cloud) but not reaching the ground or a water su ...

Broward County Broward County ( , ) is a county in the southeastern part of Florida, located in the Miami metropolitan area. It is Florida's second-most populous county after Miami-Dade County and the 17th-most populous in the United States, with over 1.94 m ...

. However, they were not considered to be directly associated with Bertha. Thunderstorms produced hail up to in diameter near

Wellington Wellington ( mi, Te Whanganui-a-Tara or ) is the capital city of New Zealand. It is located at the south-western tip of the North Island, between Cook Strait and the Remutaka Range. Wellington is the second-largest city in New Zealand by metr ...

, as well as wind gusts estimated up to . In and around Miami, the rains flooded homes and roadways, especially in close proximity to canals. Some homes even reported partial roof collapses throughout Hallandale Beach and Hollywood as a result of the heavy precipitation. Local police in El Portal asked that the South Florida Water Management District open floodgates to relieve flooding in those canals. Floodwaters entered vehicles and buildings in Miami Beach and

Hialeah Hialeah ( ; ) is a city in Miami-Dade County, Florida, United States. With a population of 223,109 as of the 2020 census, Hialeah is the sixth-largest city in Florida. It is the second largest city by population in the Miami metropolitan area, whi ...

, prompting several water rescues. Hialeah's mayor asked residents to remain indoors accordingly. Days of heavy rainfall prompted local National Weather Service offices to issue flash flood warnings, and sporadic severe thunderstorms prompted additional advisories. Strong wind gusts uprooted a tree onto Route A1A. As the low associated with Bertha moved northeastward, it also produced minor flooding near St. Augustine due to heavy rainfall. Unsettled weather related to Bertha forced the cancellation of the planned

Crew Dragon Demo-2 Crew Dragon Demo-2 (officially Crew Demo-2, SpaceX Demo-2, or Demonstration Mission-2) was the first crewed test flight of the Crew Dragon spacecraft. The spacecraft, named '' Endeavour'', launched on 30 May 2020 on a Falcon 9 booster, and ca ...

launch on May 27 from Cape Canaveral. Damage across the state was estimated at $71,000.

Carolinas

Ahead of Bertha's development, the NHC warned of the potential that the system could cause flash flooding, dangerous marine conditions, life-threatening surf and rip currents. Upon Bertha's development, the NHC issued a

tropical storm warning Tropical cyclone warnings and watches are alerts issued by national weather forecasting bodies to coastal areas threatened by the imminent approach of a tropical cyclone of tropical storm or hurricane intensity. They are notices to the local popul ...

for the South Carolina coastline from

Edisto Beach Edisto Beach is a town in Colleton County, South Carolina, United States. Edisto Beach's population was 414 as of the 2010 census, down from 641 in 2000. The town limits include only the developed coastal area of Edisto Island within Colleton Coun ...

to South Santee River, only an hour before landfall. The National Hurricane Center warned that given very saturated antecedent conditions, rainfall from Bertha could produce life-threatening flash flooding and river flooding. The 2020 Alsco Uniforms 500, held in Charlotte, North Carolina, was also postponed a day due to the possibility of bad weather. Upon moving ashore, Bertha produced a small storm surge, causing some

coastal flooding Coastal flooding normally occurs when dry and low-lying land is submerged by seawater. The range of a coastal flooding is a result of the elevation of floodwater that penetrates the inland which is controlled by the topography of the coastal land ...

Wrightsville Beach, North Carolina Wrightsville Beach is a town in New Hanover County, North Carolina, United States. Wrightsville Beach is just east of Wilmington and is part of the Wilmington Metropolitan Statistical Area. The population was 2,477 at the 2010 census. The town c ...

recorded water levels above normal, the highest tides related to the storm. Bertha also dropped rainfall across South Carolina, reaching in some locations. Wind gusts on land reached in

Winyah Bay The Winyaw were a Native American tribe living near Winyah Bay, Black River, and the lower course of the Pee Dee River in South Carolina. The Winyaw people disappeared as a distinct entity after 1720 and are thought to have merged with the Wacc ...

. Floods in Charleston, South Carolina inundated streets and cars. A few streams exceeded their banks in Lancaster County, flooding some bridges. Minor power outages occurred throughout South Carolina. A drowning was reported in

Myrtle Beach Myrtle Beach is a resort city on the east coast of the United States in Horry County, South Carolina. It is located in the center of a long and continuous stretch of beach known as "The Grand Strand" in the northeastern part of the state. Its ...

due to rip currents from Bertha after the storm made landfall. Heavy rainfall in North Carolina flooded roads and streams near

Charlotte Charlotte ( ) is the most populous city in the U.S. state of North Carolina. Located in the Piedmont region, it is the county seat of Mecklenburg County. The population was 874,579 at the 2020 census, making Charlotte the 16th-most populo ...

. The storm's remnants spawned a brief EF0

in northern

Warren County Warren County is the name of fourteen counties in the USA. Some are named after General Joseph Warren, who was killed in the Battle of Bunker Hill in the American Revolutionary War: * Warren County, Georgia * Warren County, Illinois * Warren County ...

, which destroyed a building and uprooted a few trees. Damage caused by tornado was estimated at $50,000, although it was not considered to be directly associated with Bertha. At least ten people required rescue in Surf City from rip currents.

Elsewhere

The remnants of Bertha later brought rainfall to West Virginia, resulting in flash flooding in Kanawha County that inundated some roads. Statewide damage was estimated at $16,000. Rainfall from Bertha extended into northeastern Ohio, where it was the earliest former tropical cyclone to affect the state on record.

Pittsburgh Pittsburgh ( ) is a city in the Commonwealth of Pennsylvania, United States, and the county seat of Allegheny County. It is the most populous city in both Allegheny County and Western Pennsylvania, the second-most populous city in Pennsylva ...

, Pennsylvania recorded of rainfall related to the storm.

References

External links

*The NHC'
advisory archive on Tropical Storm Bertha
{{DEFAULTSORT:Bertha Bertha (2020) Hurricanes in Canada Hurricanes in Florida Hurricanes in New York (state) Hurricanes in North Carolina Hurricanes in Ohio Hurricanes in Pennsylvania Hurricanes in South Carolina Hurricanes in Virginia 2020 Atlantic hurricane season Bertha (2020) Tropical cyclones in 2020