Over 20 Inches of Rain Triggers Historic Flash Flooding In Parts of the South (FORECAST)

Quincy Vagell
Published: March 10,2016
Torrential rainfall continues to swamp parts of the South, smashing March records, and triggering major flash flooding and worsening river flooding in parts of Louisiana, Texas, Arkansas and Mississippi. Heavy rain has also spread into parts of western Tennessee and western Kentucky.
Over 20 inches of rain has fallen near Monroe, Louisiana, prompting numerous rescues. Flash flood emergencies remained in effect Thursday morning in Shreveport, Louisiana, where up to 16 inches of rain had fallen in the metro area. Flooding also inundated homes in Greenville, Mississippi, and Dermott, Arkansas.
(MORE: Latest Flood News | Interactive Storm Reports Map)
Record flooding is now forecast along a stretch of the Sabine River next week along the Texas/Louisiana border, due to record releases from Toledo Bend Reservoir, first put in service in 1966. In some locations, the river may see levels not seen since 1884.
For river stage forecasts, storm reports and historical perspective on this event, scroll down a bit.
First, let's hit on what's going on right now and the latest rainfall forecast.
Currently, a large swath of heavy rain continues from the Texas and Louisiana Gulf Coasts to the Lower Ohio Valley.

Radar, Watches and Warnings

Unfortunately, the heavy rain threat will persist in the Lower Mississippi Valley through Saturday, all too slowly shifting east each day.
Thus, flash flooding will persist, and moderate to major river flooding in some areas will occur into this weekend once water drains from smaller tributaries to mainstem rivers.
(MORE: Your Vehicle Can Be Biggest Danger In Flash Flooding)
Among the cities not yet hit hard that should be alert for potential flash flooding the next few days are Memphis, Jackson, Mississippi, and New Orleans.
Below is a breakdown of the rainfall and some notable river flood forecasts the next several days.
Additional Rainfall Forecast

• Thursday: Areas of heavy rain persist from east Texas into western and northern Louisiana, Arkansas, western Mississippi, west Tennessee and western Kentucky. The heaviest rain should end in east Texas and western Louisiana later in the day.
• Friday: Lingering heavy rain in Louisiana, Mississippi, Arkansas. We can't rule out other lingering areas of rain or showers persisting near the upper-level low in parts of central or east Texas, but any heavy rain should be very localized, not widespread.
• Saturday: Bands of locally heavy rain may still persist near the northern Gulf Coast from southeast Louisiana and Mississippi to Alabama and the Florida panhandle. Pockets of moderate to locally heavy rain may linger as well farther north in parts of Arkansas and southeast Missouri.
• City Forecasts: Houston | Shreveport | Little Rock | Jackson | New Orleans | Mobile
• MAPS: 7-Day Weekly Planner 

Rainfall Forecast Through March 12

Some Notable River Flooding
(Click on each link below for the latest flood forecast from the National Weather Service.)

• Bayou D'Arbonne at Lake D'Arbonne, Louisiana: Forecast to reach a level of 90 feet late this week, close to the record level of 90.8 feet. Severe flooding of some homes occurs when the level reaches 86 feet. 
• Bayou Dorcheat at Lake Bistineau, Louisiana: Topped previous record flood from April 1991. Records there date back to at least 1974. Homes are flooded at these levels.
• Big Cypress Creek (Caddo Lake) at Mooringsport, Louisiana: At level of 175 feet, nearly all non-stilted homes face flooding, according to the National Weather Service.
• Bundick Creek at Bundick Lake, Louisiana: Forecast to top 100-foot stage late this week. Numerous homes, camps flooded, according to the NWS. 
• Sabine River east of Burkeville, Texas: Forecast to top its previous record flood stage of just over 48 feet set on Feb. 1, 1999. Records date to 1884. "Widespread major to catastrophic flooding occurs" at these levels, according to the NWS.
• Sabine River at Deweyville, Texas: Record flooding possible next week, topping the previous record from 1884, due to releases from Toledo Bend Reservoir well upstream. At these levels, the town of Deweyville will likely be "isolated", with "numerous homes flooded", according to the NWS. 
• Sabine River at Logansport, Louisiana: Forecast to hit a level of 33 feet this weekend. Several homes face flooding in the city, according to the NWS.
• Sabine River at Orange, Texas: Forecast to rise above major flood stage late next week due to record releases from Toledo Bend Reservoir well upstream. At the 6-foot river stage, numerous roads and homes are subject to flooding, according to the NWS. Only 2 other times has the river reached the 6-foot stage at Orange: 1) Hurricane Ike 2008 (9.86 feet) and 2) April 25, 1913 (6.27 feet).
• Trinity River at Liberty, Texas: Forecast to rise above 29-foot stage this weekend. At that stage, "several subdivisions above Liberty begin flooding", according to the NWS.

Flood Alerts

Why This Is Happening

A massive, slow-moving, southward dip in the jet stream inched east across Mexico, then near the Gulf Coast, funneling deep, tropical moisture into parts of the South and Mississippi Valley, a rather unusual pattern for early March.
In fact, atmospheric moisture values (known to meteorologists as "precipitable water") may near or top March records from the northern Gulf Coast into the Great Lakes, values last seen this time of year during the record-shattering March 2012 heat wave.
(MORE: More Flooding in a Warming World)

These ingredients will continue to support several bouts of thunderstorms and excessive rainfall from Texas into the Mississippi Valley and surrounding areas over the next several days.

It appears that the upper level low will begin to finally pull away from the southern Plains on Saturday, gradually lessening the threat for severe thunderstorms and flooding. However, a renewed threat of thunderstorms could return by Sunday and next week.

Recap of an Historic March Flash Flood

Estimated Rainfall and Flood Reports

First, here are the highest storm-total rainfalls as of early Thursday morning, from both official observing stations and cooperative observers:

• Near Monroe, Louisiana: 20.97 inches
• Near Swartz, Louisiana: 19.06 inches
• Near Minden, Louisiana: 16.35 inches
• Bossier City, Louisiana (Barksdale AFB): 15.87 inches
• Near Hamburg, Arkansas: 13.50 inches
• Near Longview, Texas: 12.03 inches
• Near Clarksdale, Mississippi: 10.02 inches

Suffice to say, this was one of the heaviest March rain events on record in this area, more reminiscent of a tropical storm or its remnant.
Calendar-day rainfall records for any March day had already been set in the following locations:

• Corpus Christi, Texas: 5.15 inches on March 9
• Greenville, Mississippi: 5.64 inches on March 9
• Monroe, Louisiana: 10.86 inches on March 9; (their second wettest March day is now March 8, when 5.62 inches of rain fell at Monroe Regional Airport)
• Shreveport, Louisiana: 5.12 inches on March 8; (their second wettest March day is now March 9, when another 4.42 inches of rain fell)

Meteorologist and hurricane specialist Eric Blake noted the storm-total rainfall in Monroe, Louisiana, as of early Thursday morning topped the previous record for any two week period, there, in records dating to 1930.
Flooding prompted evacuations in Greenwood, Haughton, Homer, Minden and Rayville, Louisiana. Evacuations have also been performed by watercraft at Lake Mexia in Texas where flooding was reportedly comparable to what occurred there last April. In Arkansas, evacuations were ordered in Dermott where at least 10 families were displaced by floodwaters.
By Wednesday night, flooding was expanding north and northeast across the Mississippi Valley, with significant flooding impacted portions of western Tennessee. At least one water rescue was made in Union City, where numerous roads were shut down due to high water.
Flooding began Monday night west of Ft. Worth, Texas, as floodwaters swamped homes and forced water rescues. In Minden, Louisiana, water was coming into the Webster Parish Courthouse and at least 40 other buildings were flooded. Water was also reported in homes in Dixie Inn, Louisiana Tuesday evening.
Flooding wasn't the only impact of this unusual pattern.
An EF1 tornado caused damage near Cool, Texas Monday evening and an EF1 tornado touched down near Tolar, Texas, southwest of Ft. Worth Tuesday morning. An EF1 tornado also left a narrow path of damage in Stephenville, Texas early Tuesday. A squall line then surged through Ft. Worth packing a 66 mph gust at the Ft. Worth Meacham Airport and a gust to 72 mph at Interstate 820 and Blue Mound Road.
Baseball size hail pounded Voca, Texas Tuesday evening, while hail to the size of golf balls covered the ground in both Evant and Jonesboro, in Texas.
You can find out more on impacts from this storm system at the link below.
(MORE: Severe Weather and Flooding Hit the South)

Continue to check back with weather.com for updated information and forecasts in the coming days.

MORE: Southern Flooding and Severe Weather