The state of being so intoxicated one is nearly "pickled". It comes from sitting on a porch all day long and into the night while steadily drinking alcholic beverages.
Porch Drunkeness usually occurs in trailer parks, urban housing projects and backwoods locales.
"Did you see Cletus out in front of his double wide? He looked like a homeless wino."
"Yeah, he was out there early this morning too. He's porch drunk."