How did Grahm know the killer would attack him in baltimore that night?

They didin't know that night. It was a sting. In Lound's interview, he asks Graham how long he would stay in D.C. and Graham says "until we take out the Tooth Fairy". He then starts walking a specific route at a specific time to establish a routine. They are gambling that the Tooth Fairy would find that a suitable time/place to attack.

They most likely planned to be ready for an attack for a certian number of days and 'set up' each night. It's implied that Dollarhyde was casing Graham's 'walk' as he has Lound's recording say they tried to lure him into a trap in D.C., so he must have wirnessed them snagging the innocent jogger.

You just have to be resigned-
You're crashing by design

Graham knew that Dollarhyde was "interested" in him from his letter to Lecter. So there was a good chance that Dollarhyde was stalking him, and that if Graham made himself conspicuous and a seeming easy target, Dollarhyde might strike. It was a gamble that didn't pay off, but it was a plausible gamble.

He fed Lounds lines that he knew would make him angry and then banked on him retaliating. He did, just not to Graham.