Tropical downpours unleash more than 12 inches over flood-weary south-central US
Residents in Yell County, Arkansas, have been battling rising waters over several days after the levees of the Arkansas River burst at Holla Bend on May 31. The Yell County Sheriff's Department released drone footage recently revealing just how inundated the community is with flooding.
The combination of a slow-moving non-tropical storm and a weak tropical disturbance loaded with moisture is unleashing torrential rain and causing new and worsening flooding problems over the south-central United States into this weekend.
Moisture began to stream northward from the upper Texas coast to Mississippi during Wednesday morning. The plume of moisture will continue for several days over part of the lower Mississippi Valley.
This image shows heavy rainfall totals across the south-central U.S. over the past 24 hours as of 11:15 a.m. CDT on June 6, 2019.
Meanwhile, downpours associated more so from the non-tropical storm will do some damage in terms of rainfall and flooding farther inland.
Hourly rainfall of 1-3 inches can occur with daily rainfall averaging 3-5 inches.
However, there is the potential for some areas of the Interstate 10 and 20 corridors to receive a foot or more of rain from the multiple-day event that may last through the weekend.
Both Wharton and Palacios, Texas, received 8 inches of rain in less than 12 hours on Wednesday. Midfield, Texas, received just over 14 inches of rain during the event.
Rainfall of this magnitude will trigger street and poor drainage area flooding, initially. Motorists should be prepared for road closures, substantial delays and the need to alter their routes. To drive through flooded roadways is extremely dangerous.
Cities such as New Orleans and Baton Rouge, Louisiana, as well as Mobile, Alabama, and Pensacola, Florida, will be at risk for inundation in some neighborhoods through this weekend.
Some small streams and bayous will flood and ultimately trigger river flooding in areas that have not had such problems recently.
Home and property owners prone to flooding should be prepared to move valuables and seek higher ground.
A pocket of severe thunderstorms will affect the central Gulf coast into the weekend.
A small number of these storms may produce a tornado. Cities at risk for a tornado strike include New Orleans; Gulfport, Mississippi; Mobile, Alabama; and Pensacola, Florida.
To complicate matters, heavy rainfall over the Central states and melting snow from the Rockies has created a surge of water from the Missouri and Arkansas rivers that is emptying into the Mississippi River and flowing southward.
Over the lower part of the Mississippi Valley, this surge of water may occur at nearly the same time that heavy rain falls.
The combination thereof could result in record-challenging high water on the lower Mississippi River, especially where the water levels are not mitigated by spillways toward the middle and into the latter part of June.
Official forecast levels from Wednesday could be underdone over part of the Southern states along the Mississippi and other rivers depending on how far inland torrential rain occurs.
The opening of the Morganza Spillway on the Mississippi River above Baton Rouge has been pushed back to June 12, based on National Weather Service hydrologist forecasts, according to The Associated Press.
In this May 18, 2011 file photo, floodwater is seen rushing from the Mississippi River, above right, into the Atchafalaya Basin through open bays of the Morganza Spillway in Morganza, La. As the Mississippi River rises, the Army Corps of Engineers plan to open the Morganza Spillway will be opened for the third time ever — and only the second time for flood control on June 12, 2019. (AP Photo/Rich Matthews, File)
The spillway would be overtopped if not opened with the anticipated level of water. The release of water at the spillway and the Old River structure diverts some water from the main stem of the Mississippi River and creates flooding in the Atchafalaya River Basin.
The back edge of the heavy rain is forecast to make slow eastward progress this weekend.
Much of eastern Texas should be in the clear from rain by Saturday, following only isolated showers and thunderstorms on Friday. However, runoff from rains through Friday will continue to cause flooding problems.
It may take until Monday or Tuesday before the rain departs the lower Mississippi Valley.
Even well away from the stream of tropical moisture, the non-tropical storm will play more of a role with pockets of heavy rain and thunderstorms over parts of the southern Plains and the middle Mississippi Valley.
Up to 6 inches of rain fell in about 2 hours and triggered flash flooding around Oklahoma City during Thursday midday. High water closed roads, including a portion of Interstate 44 and stranded multiple vehicles.
As the corridor of torrential rain advances eastward, it will reach needy areas of the southeastern U.S. late this week and this weekend. The rainfall could provide relief from drought and abnormally dry conditions that have been building across the region. However, even in some of these eastern areas, too much rain could fall and may result in flooding.
Even in the wake of this slow-moving rainstorm, the ordeal of flooding is far from over in the South Central states this summer.
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