They say the aircraft allows them to remain a safe distance from a tornado and fly the planes into the heart of the storm to collect data.
Forecasters say the Midwest could be in for another round of strong storms and heavy rain.
The system is free to the 40,000 residents of Finney County but participation has been low.
Rain that lashed a broad swath of Texas on Wednesday brought flooding to many regions.
A couple died shielding their young daughter from a tornado as the twister chewed up the family’s mobile home.
This weekend, parts of several Great Plains states were in the path of severe weather, while a tropical storm came ashore in the Carolinas.
At 2 p.m. Sunday, the center of the depression was located about 30 miles north of Myrtle Beach.
Forecasters say there are no reports of damage after a severe storm system generated at least five tornadoes Saturday.
Emergency responders searched the wreckage of communities in northeast Texas and southwest Arkansas early Monday.
Ana was centered about 65 miles (105 kilometers) southeast of Myrtle Beach, South Carolina, as of 5 p.m. EDT,
When Park Director Bill Meadows learned his park had taken a direct hit by Wednesday’s tornado, he feared the worst.
Conditions appeared to be ripe on Friday and Saturday for storms that could produce even more powerful tornadoes.
A tropical storm warning was issued Friday for parts of North and South Carolina as Ana approached the U.S.
Numerous tornadoes tore through the state yesterday, one of which tore a part a home near Mount Hope.
The National Weather Service says it was an internal problem, and it’s been fixed.