Parade of Severe Thunderstorms, Flash Flooding Will Pound Southern Plains Into Thursday

Jon Erdman
Published: May 17,2016
Continuing what's been a wet, stormy spring, severe thunderstorms and flash flooding will again pound parts of Texas, Louisiana, and other parts of the Southern Plains and Gulf Coast into late this week.
Parts of the Texas and Oklahoma panhandles into western Oklahoma were pounded with hail larger than baseballs, wind gusts over 70 mph, tornadoes and flash flooding Monday.
For a full recap of severe weather reports over the past few days, scroll to our "reports" section below.

Latest Radar, Watches and Warnings

(MORE: View National Interactive Radar Map | Difference Between a Watch and a Warning)
Below is a look ahead at the severe weather and flood threats into the new week ahead.

Severe Storm Threat Forecast

Severe weather will remain a possibility across the region the next several days. The atmosphere will be very unstable with plenty of moisture to work with, so the strongest thunderstorms could produce damaging winds (58+ mph), large hail (1 inch diameter or larger), and a few tornadoes.
A major outbreak of severe weather with dozens of tornadoes is not expected, however.
Here is an overview of where severe storms could develop.
Tuesday: 

• The greatest chance of severe storms will be from central and southeast Texas. This could include a development of a large thunderstorm complex that may sweep through parts of east and South Texas through the night.
• Threats: Large hail, damaging winds and local flash flooding. A few tornadoes can't be ruled out.
• Cities: Austin | San Antonio | Houston | Corpus Christi

Tuesday's Thunderstorm Forecast

Flood Threat Forecast

The threat for locally heavy rainfall from thunderstorm clusters has already begun from parts of the Rio Grande Valley of central Texas into southeast Texas.
Then, as another cold front drops south and stalls out Tuesday, more rounds of thunderstorms with heavy rain are expected to occur each day and evening through Thursday in the Southern Plains.
(MAPS: 7-Day Rainfall Forecast)
By Friday, as the upper-level disturbance finally begins moving east, the heavy-rain threat shifts into the Southeast, Appalachians and Mid-Atlantic states, with a threat of local flash flooding from Florida to the Delmarva Peninsula.
This includes recently-dry parts of the southern Appalachians and adjacent piedmont of the Carolinas, which were recently classified in moderate drought, according to the latest Drought Monitor analysis.
(FORECAST: San Antonio | Pensacola | Asheville | Roanoke | Washington D.C.

Forecast Rainfall Into This Weekend

Storm Reports Through Monday

Monday, a cluster of severe t-storms rumbled through the panhandles of Texas and Oklahoma.
Hail up to 3 inches in diameter (somewhat larger than baseball size) damaged vehicle windshields southeast of Masterson, Texas.

Strong thunderstom winds snapped power poles near Spearman, Texas. Thunderstorm wind gusts from 60-75 mph were measured in over a dozen locations in the panhandles into western Oklahoma Monday evening.
There were eight reports of tornadoes according to the Storm Prediction Center, most staying out in open country. Trees were uprooted east and southeast of Canadian, Texas, from an apparent tornado.
Early Monday morning, major flash flooding hit the Corpus Christi area with numerous water rescues reported throughout the city. Water was reportedly over the roofs of cars in the southeast part of town. Some residents of Ingleside had to be rescued from their homes. One location southeast of Corpus Christi picked up 11.51 inches of rain in the 24 hours ending Monday morning. For more details on this story, see the link below.
(LATEST NEWS: Major Flooding Hits Southeast Texas)
On Saturday, water rescues from vehicles were reported on the southwest side of Houston in Bellaire, Meyerland, and Westbury. Locally 4-5 inches of rain fell in the area during a short period of time. On Sunday, roads were flooded near Marathon, Texas and near Kingsville, Texas.
(MORE: Is Houston America's Flood Capital?)

Setup

A series of disturbances will track through the Southern Plains this week as the southern branch of the jet stream becomes more active.
By mid-to-late week, a more pronounced upper-level southward dip in the jet stream will swing out of the Desert Southwest into the Plains, triggering what should be the most significant round of thunderstorms in the Southern Plains, Lower Mississippi Valley, Deep South and Gulf Coast mid-late week.
A persistent south to southeast wind off the Gulf of Mexico will provide a plethora of moisture to fuel thunderstorm development. Therefore, any storms that form will have the potential to dump very heavy rainfall.

The setup for repeated rounds of thunderstorms with locally heavy rain in parts of the Southern Plains and Gulf Coast over the next several days.

Parts of Texas and Louisiana are already flood-fatigued after April's flood and several other floods over the past year, and they do not need anymore significant rain.

How Wet has it Been?

Houston has received over 74 inches of rain in the past 12 months, placing it as the wettest 12-month period ending on May 12 of any year.
This shatters the previous record for this period of 68.25 inches by about 6 inches. Houston currently sits at 24.8 inches of precipitation above average for this 12-month period, with Abilene, Dallas, and Austin also 20 to 25 inches above average over the past 12 months.
Some rivers in east Texas, Louisiana and Arkansas are still above flood stage, and soil moisture remains much higher than average in these areas, meaning even relatively brief heavy rainfall may quickly run off and trigger flash flooding.

MORE: Texas Flooding April 2016