No....they will usually use linked repeaters. For example, the Ft Worth office will use a repeater in Gainsville that is on a 2,000 foot tower for work between Dallas and the Red River (Oklahoma border). I can roam for 90 miles in any direction of that tower. If I get on a fringe and am about to go out of its range, I just ask what frequency I should move to, and they help me figure out what linked repeater I am moving into range of.
The Norman OK office was coming to me on a repeater in the Arbuckle mountains, near Davis/Sulphur.
There is a placefile for GRLevel3 that shows all the Skywarn repeaters, and I also have a repeater directory in the truck. However, to be honest, they are out of date as soon as they are put up, so you usually have to ask a local person you find by scanning the band.