Flood Threat Continues in the Central States (FORECAST)

Jon Erdman
Published: May 11,2015 



 
We've seen multiple major flash flood events in the past week in the Plains from Nebraska to Texas.
(RECAPS: Nebraska | North Texas | Okla. City | Manhattan, Kansas)
Unfortunately, more rain is expected in the south-central states in the new week ahead.

Flooding Recap

Estimated Rainfall

On Sunday, numerous storms dumped heavy rain over northern Texas, creating flash flooding conditions and swift water rescues in Krum and Sanger, Texas. The National Guard rescued numerous people who were trapped in their homes, as well as a pair of people stuck when their truck washed away in flood waters. The National Weather Service says that radar estimated more than 12 inches of rain just southeast of Corsicana, Texas. A total of 10.02 inches of rain was measured in Corsicana during a 5-hour period on Sunday.
(MORE: National Guard Performs Swift Water Rescues as Flood Waters Rise in North Texas Sunday)
Thursday, torrential rain pounded parts of north Texas, including areas hammered by heavy rain early in the week north of Dallas. A train derailed near Valley View, Texas thanks to flood-damaged tracks. Interstate 35 was shut down for a time near the town. Numerous water rescues were performed in Gainesville and Denison, Texas.
On Wednesday, severe thunderstorms produced not just tornadoes, but heavy rains as well throughout the Oklahoma City region. As much as 3 inches fell within one hour at Will Rogers Airport on Wednesday, and a calendar day total of 7.1 inches was recorded as well. So much rain fell so quickly that a flash flood emergency was issued for the metro area.
Last Monday, significant flash flooding was reported in Manhattan, Kansas, Lubbock, Texas, and Seagraves, Texas. Monday was the third wettest May day on record in Lubbock (3.42 inches), and Manhattan, Kansas, picked up over 4 inches of rain.

Forecast: More Rain Ahead

Rainfall Forecast Through Monday

Radar, Flood Alerts

A front will stall over parts of south Texas, then return northward midweek and interact with an upper disturbance. This will bring a locally heavy rain threat back in play to parts of the southern Plains.
Through Tuesday, the greatest chance of flash flooding will exist in south-central and southeast Texas, including Austin and San Antonio. A flood watch has been issued by the National Weather Service for these areas.
Tuesday night into Wednesday night, widespread showers and storms will develop in north and west Texas and Oklahoma. Given the saturated ground conditions, flash flooding is possible once again in these areas and flash flood watches have been issued in these areas as well.
Through Thursday, we expect additional rainfall amounts of 1-2 inches from parts of Texas to Oklahoma and Kansas. Heavier amounts in excess of 3 inches are possible in southern Texas.
(MAPS: 7-Day Weekly Planner)
However, the potential exists for slow-moving thunderstorm clusters to stall in a given area, quickly wringing out several inches of rain in 1-3 hours.
(INTERACTIVE: Radar Loop | Flood Alerts)
These rapid rain rates may quickly trigger flash flooding, particularly in areas that may have received heavy rain the previous days. Local flash flooding may also occur even in areas that had been rather dry recently.
(MORE: Your Vehicle...Biggest Flood Danger)

Late April/early May Drought Monitor analysis from 2011 through 2015. Brown box denotes area in southern Plains of most persistent drought since 2011.

Three-month change in the Drought Monitor analysis ending April 28, 2015. Green shading indicates areas where the drought has improved. Yellow and orange shadings indicate areas with worsening drought.
(USDA/NDMC/NOAA)

Good News: Optimal Spring Drought Relief

While California is getting much of the nation's attention on the drought front, another long-term drought continues in the nation's heartland.
Parts of the southern and central Plains have been struggling in drought since fall 2010.
According to the Texas Water Development Board, most reservoirs in northwest and west-central Texas, as well as the Texas panhandle, are still running at less than half of capacity.
O.C. Fisher Lake, a secondary drinking water source for San Angelo, Texas, is still at only 0.5 percent of capacity. About 10 other reservoirs in northwest and western Texas are also running at less than 10 percent capacity.
The news isn't all bad in the Lone Star State. Most reservoir levels generally along and east of I-35 from the Red River to Austin are running at least 80 percent of capacity.
Also, 2015 has been wetter in the southern Plains. Above-average precipitation has fallen in Amarillo, Oklahoma City and Wichita Falls, Texas.
Recent heavy rain has brought up the level of Lake Kickapoo, one of the reservoirs supplying the city of Wichita Falls, to above 50 percent of capacity for the first time in several years. The lake level had risen over 6.5 feet in just two days from May 6-8.
While it will likely take at least one, if not multiple wet years to fully recharge still-depleted southern Plains reservoirs, the wet pattern over the next several days is about as lucrative for a short-term drought dent as you can draw up in the middle of spring.
(FORECAST: Dallas | Okla. City | Amarillo | Wichita)
Drought relief is easier to come by in the spring compared to the summer, when the jet stream migrates well to the north, leaving the southern Plains often subject to hot, dry high-pressure aloft, evaporating water from reservoirs.
In the absence of a remnant tropical cyclone, it's difficult to get widespread, significant drought-denting summer rain in the southern Plains.
Interestingly, a dry winter has left parts of the northern Plains and Upper Midwest in moderate to locally severe drought, according to the May 5 Drought Monitor analysis.
The recent warmth and dry weather has allowed farmers an early start on spring planting. However, rain is needed in parts of the Dakotas, Minnesota and Wisconsin.
While not as high a flood threat, some locally heavy rain is also expected to spread into these areas mid-to-late week.

MORE: Severe Outbreak May 8-10, 2015