There were only a few of these more flashy Warblers. Nashville and Mourning Warblers both have yellow breasts and gray heads but what's under the chin is what distinguishes them. The Mourning Warblers have dark gray to black like a veil or hood. Northern Parulas are more blue gray with yellow on their chest with a colorful ban of rust.
Mourning - Not as clear as the others but the black under the gray hood can be seen.