A bit of a misnomer - this may occur after noon, and it isn't for a period of an hour. An explanation of the practice is -
"the House of Representatives meets earlier than the hour established for that day’s session for a period called “morning hour debates” (also known as “morning hour speeches”). This period provides a rare opportunity for non-legislative debate in the House; remarks in the House are usually limited to pending legislative business. During morning hour debates, individual Members deliver speeches on topics of their choice for up to five minutes.
The majority and minority leaders give the Speaker a list showing how each party’s time for morning hour debates will be allocated among its Members. The chair follows this list in recognizing Members for morning hour debates. At the conclusion of morning hour debates, the House recesses until the starting time for that day’s session."
In the video below, a message is received from the Speaker, appointing Chip Cravaack, a freshman from the 8th District of Minnesota, to act as Speaker pro tempore. The "morning hour debates" are then commenced