Category: Posts EN

 

Months of torrential rainfall have affected much of the Mississippi River watershed. Major tributaries have been setting new record crests in recent weeks. Now those flood waters are entering the already swollen Mississippi, creating major headaches for downstream locations.

 

 

The map above shows deviations from normal rainfall over the past six months. As you can see, excess rainfall of 10-20 inches has fallen across much of the Mississippi River watershed from the Plains through the Midwest to the Ohio Valley. Numerous gauges along the Mississippi have been in the major flood stage for weeks if not months. Unfortunately, moisture from a tropical low moving slowly north in the western Gulf won’t help (see map below). Expect widespread showers and storms in the coming days that will add up to an additional 4-5 inches (100-125 mm) of rain in some areas.

 

 

Ironically, considering the magnitude of river flooding in the area, much of southeast Louisiana has actually seen near-normal rainfall over the past several months. However, the tremendous surge of flood waters from upstream have kept the river well above flood stage for months. River levels are so high, in fact, that officials have announced plans to open the Morganza Spillway as early as this weekend. If they were to open it, it would be for only the third time since the construction of the spillway in 1954. Likewise, the Bonnet Carre Spillway has been opened multiple times in the same calendar year for the first time ever. Lead photo courtesy US Air Force.

 

A pattern of rich, warm Gulf moisture surging into an area of strong upper level winds over the Plains and Midwest has persisted since mid-May. The result has been waves of severe storms developing on a daily basis, hammering the same regions time and time again. These severe cells have put down over 200 tornadoes in the past two weeks.

 

 

The record for consecutive days with at least eight tornado reports was broken on May 28th. More tornadic storms on Wednesday (29-May) extended the record to 13 days. Of these tornadoes, 47 have been classified as EF-2 intensity after careful analysis by National Weather Service meteorologists. The EF (Enhanced Fujita) scale is based on the nature and severity of the damage the tornado causes. Those rated EF-2 and EF-3 are considered “strong” tornadoes, while EF-4 and EF-5 rated twisters are classified as “violent”. Only one tornado so far in the outbreak has been rated EF-4, the one that leveled Linwood, Kansas on Tuesday (28-May). However, even EF-2 and EF-3 tornadoes produce devastating wind speeds of 111-165 mph (180-265 kph)!

 

@ReedTimmerAccu right in our backyard last night. Linwood, KS. Awful destruction. pic.twitter.com/utWwLaW1Ww

— Luke Terrell (@LTerrell10) May 29, 2019

 

Aerials showing the #tornado destruction across Linwood, KS Video courtesy of @Johnny_Rowlands at @kmbc #KSwx #severe pic.twitter.com/JMEMs4Pk0M

— Mike Seidel (@mikeseidel) May 29, 2019

 

This outbreak has been historic not only for its persistence, but for the major population centers that have been directly impacted. Over the past few weeks the following cities have been hit by EF-3 storms:

• Jefferson City, MO (pop 42,838) on 22-May
• Dayton, OH (pop 140,640) on 27-May
• Lawrence, KS (pop 96,892) on 28-May

The Jefferson City and Dayton tornadoes were made all the more dangerous by the fact that they struck late in the evening, potentially catching some residents asleep and off-guard. Damage estimates are still being tallied, but costs will likely run at least into the tens of millions of dollars. One saving grace has been that warnings have been timely and accurate from the National Weather Service. As a result, despite the devastation to homes and businesses, relatively few lives have been lost, likely less than ten for the entire outbreak.

 

Widespread, record-threatening rainfall has hammered the Plains and Mississippi Valley in the past several weeks. Totals of more than 20 inches (500 mm) have been recorded in parts of Kansas, Missouri, and Oklahoma, at least six times the norm (see map below). The pattern is also responsible for the deadly tornadoes from the Plains to the Midwest.

 

 

In order to relieve pressure on the Keystone Dam just west of Tulsa, officials Monday increased flood output to 275,000 cubic feet per second (CFS). That’s nearly 8 million liters per second! This tremendous release is causing severe flooding downstream. The Arkansas River at Tulsa is expected to reach 23 feet (7 m), the second highest depth ever reached. Flooding of numerous homes and businesses will occur, especially on the south side of the Tulsa metro.

 

 

Just east and downstream from Tulsa the Arkansas River joins the Verdigris and Neosho Rivers (see map above). Many gauges on these two rivers are also in the major flood category. The additional water from these swollen tributaries will make for record-shattering floods downstream towards Van Buren, Arkansas and beyond. The previous record gauge level there is expected to be surpassed by more than four feet! In fact, every gauge downstream from Ft. Smith to Little Rock will see record-setting crests in the next several days. Lead photo courtesy Wikipedia user Jill Carlson.

 

FLOODING: Seen on approach to Fort Smith, AR … The Arkansas River is already at a record level and not expected to crest until Tuesday. We’re covering for @CBSThisMorning #CTM pic.twitter.com/bIuUL3FOHe

— Manuel Bojorquez (@BojorquezCBS) May 26, 2019

 

Moffett, OK with the Arkansas River at a new all time record high… with several more feet to go! #okwx #flooding pic.twitter.com/mWbk77AOjD

— Brian Emfinger (@brianemfinger) May 27, 2019

 

The active week of severe weather continued on Wednesday and Thursday with more tornadoes, large hail, and damaging winds. The total tally of tornado reports for the week is up to 130 and still counting! One tornadic supercell was particularly long-lived, dropping killer tornadoes from northeast Oklahoma through southeast Kansas and across central Missouri Wednesday evening.

 

This was the home of 86-year-old Gene Harris and his 83-year-old wife, Opal. They were killed by the tornado that hit near Golden City, MO Wednesday night. pic.twitter.com/jQg3fLxU4y

— Bianca Beltrán (@KMBCBianca) May 23, 2019

 

WATCH: Deadly storms hit Missouri Wednesday night, including a “violent tornado” that caused catastrophic damage in the state’s capitol https://t.co/2QbrwKmLfS pic.twitter.com/2KrWPTZmG0

— CBS News (@CBSNews) May 23, 2019

 

The storm in question developed early Wednesday evening just north of Tulsa. Its first tornado was observed just before 8 pm CT near Welch, OK. Initially it was a relatively weak twister that soon clipped far southeastern Kansas. The storm gained strength as it crossed into southwest Missouri, however. National Weather Service employees found category three damage on the Enhanced Fujita (EF) scale between Carl Junction and Golden City, MO. That’s consistent with wind speeds of 140-160 mph (230-260 kph)! The tornado claimed three lives in Golden City on Wednesday. Coincidentally, it was the eighth anniversary of the infamous EF-5 twister that took 160 lives in nearby Joplin.

 

 

The supercell weakened somewhat for a few hours as it rolled towards central Missouri. However, ominous signs of increasing rotation began to appear on radar after 11 pm as the storm approached the state capital of Jefferson City. Sure enough, another monster tornado soon developed, ripping across eastern and southern portions of the city. Banks, homes, businesses, and schools were all destroyed with almost a dozen serious injuries, although fortunately no deaths. Survey teams have found damage of high-end EF-3 rating so far with analysis continuing.