Incessant storms keep flood risk high in Texas, Louisiana
By
Alex Sosnowski, AccuWeather senior meteorologist
Updated Jun 4, 2021 9:48 AM EDT
A relentless pattern of persistent showers and thunderstorms is not showing signs of easing across parts of waterlogged Texas and Louisiana. And to make matters more concerning, AccuWeather meteorologists say that a storm and tropical moisture from the Gulf of Mexico may team up to aggravate existing flooding and potentially lead to new flooding problems.
The initial flooding concern will be the result of a storm in the middle levels of the atmosphere that is forecast to form over Texas later this week and crawl eastward through next week, according to AccuWeather Senior Meteorologist Brett Anderson.
"That mid-level storm will trigger drenching showers and locally severe thunderstorms and incidents of flash flooding over a several-day period mainly from Friday to Sunday," Anderson said.
The slow-moving storm and its circulation will pump Gulf of Mexico moisture northward over much of Texas and Louisiana as well as neighboring portions of Oklahoma, Arkansas and Mississippi.
The new batch of flooding rain is coming to an area that had more than its fair share in May.
Both Victoria, Texas, and Lake Charles, Louisiana, received more than 20 inches of rain during May, which was nearly four times the normal rainfall for the month for each city, and much of that rain fell in a mere 10 days.
The tremendous rainfall was not just isolated to these two cities. Rainfall totals in the double digits were reported from parts of the lower Rio Grande Valley to central Texas and much of southern Louisiana. Houston, Port Arthur and Austin, Texas, as well as New Orleans and Lafayette, Louisiana, all received double-digit rainfall during May.
The May rainfall has left the ground saturated in many locations from central Texas to southern Louisiana. Area streams, rivers and bayous are swollen to the point where flooding from prior rainfall has continued into the start of June.
The Trinity River at Liberty, Texas, a city located northeast of Houston, teetered at major flood stage of 29 feet during much of the Memorial Day weekend, according to National Weather Service hydrological data. The Trinity was only receding at a snail's pace as of Wednesday. Long-range water level projections on the Trinity and other rivers in the region were not incorporating the potential amount of rain that may fall in the next week to 10 days.
Even smaller creeks in central and western Texas periodically swelled rapidly to moderate and major flood stage over the holiday weekend with more rounds of storms on the way.
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However, it is not just this week's mid-level storm that will be a problem. Showers and thunderstorms from a moist flow of air from the Gulf will occur before and after the storm's direct impact.
"Regardless of what weather systems happen to be in the neighborhood, this is a pattern that is ripe for multiple rounds of showers and thunderstorms that focus on areas of central and east Texas and Louisiana that have been inundated in recent weeks with frequent heavy rain events and flooding," AccuWeather Senior Meteorologist Joe Lundberg said.
Early signs of tropical development?
Atlantic hurricane season is officially underway, and while one named system has already formed, forecasters are tracking long-range forecasts in an effort to glean insight into when the second organized system could take shape.
AccuWeather's team of tropical weather experts says these forecasts are beginning to reveal signs of potential tropical development in the western Caribbean and perhaps the Gulf of Mexico during the second week of June.
Occasionally, storms in the middle levels of the atmosphere can spin some energy down to the surface and allow a tropical system to slowly evolve.
There is a remote chance of a low-end tropical system that may form near the northwestern Gulf coast next week provided wind shear eases up in the region.
Wind shear is the change in direction or increase in speed of breezes from near the sea surface to higher levels in the atmosphere. When wind shear is strong, it can prevent tropical development or cause established tropical systems to weaken.
In lieu of any tropical development, a plume of tropical moisture is likely to persist in the area from eastern Texas to Louisiana and the central Gulf Coast to the lower part of the Mississippi Valley next week, after the storm in the middle part of the atmosphere breaks down.
While the pattern may not evolve into another Harvey with record rainfall and catastrophic flooding in a concentrated area, torrential rainfall may affect broad areas of Texas and Louisiana and could result in moderate to major flooding going forward, Lundberg said.
Harvey, which peaked as a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale before making landfall in Texas in the summer of 2017, caused catastrophic flooding and $125 billion in damage as it unloaded up to 61 inches of rain on the Port Arthur, Texas, area and unleashed between 40 and 55 inches of rain on the Houston area spanning Aug. 25 to Sept. 1. The 60.58 inches of rain that fell near Nederland, Texas, set a U.S. rainfall record for any storm system.
Just two years later, another multiday flood disaster occurred. Tropical Storm Imelda struck southeastern Texas and unloaded a total of 44.29 inches near the town of Fannett from Sept. 17-19. With that storm total, Imelda is considered to be the fifth-wettest tropical cyclone on record for the contiguous U.S.
Even if a tropical system fails to form or move over the area projected to be slammed by heavy rain into the second week of June, a general 5-10 inches of additional rain is projected to fall from Friday, June 4, through Wednesday, June 9, from southeastern Texas to western Louisiana and into western Arkansas. An AccuWeather Local StormMax™ of 24 inches is projected to fall in isolated areas.
"Many major metropolitan areas will be affected by heavy rain and some degree of flooding from central and southeastern Texas to central and southern Louisiana in one way or another during the first half of June in lieu of a tropical system strike," Lundberg said.
While the money saved on cooling costs during the cloudy and wet pattern may be substantial, some communities could be overwhelmed by the costs related to flooding damage and cleanup.
Motorists should anticipate travel disruptions in the coming days as rainfall continues and more low water crossings and underpasses are inundated by rising water from streams and storm drainage systems.
In addition to the risk of problems ranging from flash flooding to river flooding, some of the thunderstorms in the region can periodically reach severe levels and produce isolated incidents of damaging winds, large hail and even an isolated tornado into next week.
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
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News / Severe Weather
Incessant storms keep flood risk high in Texas, Louisiana
By Alex Sosnowski, AccuWeather senior meteorologist
Updated Jun 4, 2021 9:48 AM EDT
A relentless pattern of persistent showers and thunderstorms is not showing signs of easing across parts of waterlogged Texas and Louisiana. And to make matters more concerning, AccuWeather meteorologists say that a storm and tropical moisture from the Gulf of Mexico may team up to aggravate existing flooding and potentially lead to new flooding problems.
The initial flooding concern will be the result of a storm in the middle levels of the atmosphere that is forecast to form over Texas later this week and crawl eastward through next week, according to AccuWeather Senior Meteorologist Brett Anderson.
"That mid-level storm will trigger drenching showers and locally severe thunderstorms and incidents of flash flooding over a several-day period mainly from Friday to Sunday," Anderson said.
The slow-moving storm and its circulation will pump Gulf of Mexico moisture northward over much of Texas and Louisiana as well as neighboring portions of Oklahoma, Arkansas and Mississippi.
The new batch of flooding rain is coming to an area that had more than its fair share in May.
Both Victoria, Texas, and Lake Charles, Louisiana, received more than 20 inches of rain during May, which was nearly four times the normal rainfall for the month for each city, and much of that rain fell in a mere 10 days.
The tremendous rainfall was not just isolated to these two cities. Rainfall totals in the double digits were reported from parts of the lower Rio Grande Valley to central Texas and much of southern Louisiana. Houston, Port Arthur and Austin, Texas, as well as New Orleans and Lafayette, Louisiana, all received double-digit rainfall during May.
The May rainfall has left the ground saturated in many locations from central Texas to southern Louisiana. Area streams, rivers and bayous are swollen to the point where flooding from prior rainfall has continued into the start of June.
The Trinity River at Liberty, Texas, a city located northeast of Houston, teetered at major flood stage of 29 feet during much of the Memorial Day weekend, according to National Weather Service hydrological data. The Trinity was only receding at a snail's pace as of Wednesday. Long-range water level projections on the Trinity and other rivers in the region were not incorporating the potential amount of rain that may fall in the next week to 10 days.
Even smaller creeks in central and western Texas periodically swelled rapidly to moderate and major flood stage over the holiday weekend with more rounds of storms on the way.
CLICK HERE FOR THE FREE ACCUWEATHER APP
However, it is not just this week's mid-level storm that will be a problem. Showers and thunderstorms from a moist flow of air from the Gulf will occur before and after the storm's direct impact.
"Regardless of what weather systems happen to be in the neighborhood, this is a pattern that is ripe for multiple rounds of showers and thunderstorms that focus on areas of central and east Texas and Louisiana that have been inundated in recent weeks with frequent heavy rain events and flooding," AccuWeather Senior Meteorologist Joe Lundberg said.
Early signs of tropical development?
Atlantic hurricane season is officially underway, and while one named system has already formed, forecasters are tracking long-range forecasts in an effort to glean insight into when the second organized system could take shape.
AccuWeather's team of tropical weather experts says these forecasts are beginning to reveal signs of potential tropical development in the western Caribbean and perhaps the Gulf of Mexico during the second week of June.
Occasionally, storms in the middle levels of the atmosphere can spin some energy down to the surface and allow a tropical system to slowly evolve.
There is a remote chance of a low-end tropical system that may form near the northwestern Gulf coast next week provided wind shear eases up in the region.
Wind shear is the change in direction or increase in speed of breezes from near the sea surface to higher levels in the atmosphere. When wind shear is strong, it can prevent tropical development or cause established tropical systems to weaken.
In lieu of any tropical development, a plume of tropical moisture is likely to persist in the area from eastern Texas to Louisiana and the central Gulf Coast to the lower part of the Mississippi Valley next week, after the storm in the middle part of the atmosphere breaks down.
While the pattern may not evolve into another Harvey with record rainfall and catastrophic flooding in a concentrated area, torrential rainfall may affect broad areas of Texas and Louisiana and could result in moderate to major flooding going forward, Lundberg said.
Harvey, which peaked as a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale before making landfall in Texas in the summer of 2017, caused catastrophic flooding and $125 billion in damage as it unloaded up to 61 inches of rain on the Port Arthur, Texas, area and unleashed between 40 and 55 inches of rain on the Houston area spanning Aug. 25 to Sept. 1. The 60.58 inches of rain that fell near Nederland, Texas, set a U.S. rainfall record for any storm system.
Just two years later, another multiday flood disaster occurred. Tropical Storm Imelda struck southeastern Texas and unloaded a total of 44.29 inches near the town of Fannett from Sept. 17-19. With that storm total, Imelda is considered to be the fifth-wettest tropical cyclone on record for the contiguous U.S.
Even if a tropical system fails to form or move over the area projected to be slammed by heavy rain into the second week of June, a general 5-10 inches of additional rain is projected to fall from Friday, June 4, through Wednesday, June 9, from southeastern Texas to western Louisiana and into western Arkansas. An AccuWeather Local StormMax™ of 24 inches is projected to fall in isolated areas.
"Many major metropolitan areas will be affected by heavy rain and some degree of flooding from central and southeastern Texas to central and southern Louisiana in one way or another during the first half of June in lieu of a tropical system strike," Lundberg said.
While the money saved on cooling costs during the cloudy and wet pattern may be substantial, some communities could be overwhelmed by the costs related to flooding damage and cleanup.
Motorists should anticipate travel disruptions in the coming days as rainfall continues and more low water crossings and underpasses are inundated by rising water from streams and storm drainage systems.
In addition to the risk of problems ranging from flash flooding to river flooding, some of the thunderstorms in the region can periodically reach severe levels and produce isolated incidents of damaging winds, large hail and even an isolated tornado into next week.
Related:
Keep checking back on AccuWeather.com and stay tuned to the AccuWeather Network on DirecTV, Frontier, Spectrum, FuboTV, Philo, and Verizon Fios.
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