Navion pilot reported an abrupt yaw just after takeoff when the engine cowl opened. The pilot immediately landed the aircraft on the takeoff runway; departed the runway surface and impacted runway edge lights.

Narrative

On initial takeoff from Runway XX at ZZZ; the left side engine cowling popped open. The open cowl caused a large abrupt yaw and the decision was made to abort the takeoff. Touchdown occurred on the far right side of the runway and on rollout the aircraft departed the surface to the right; impacting several runway lights. The problem arose due to an interrupted preflight. I had flown to ZZZ to meet up with other Navion aircraft in order to fly a formation arrival at ZZZ1. During brief enroute stops I always open the engine cowling to preclude hot start problems. My cowlings latch wide open so there is no chance of forgetting to close them before engine start. I was in the process of closing the left cowl when one of my formation pilots asked for something. I had released the upper latch so the cowl was flush to the aircraft but I had not secured the three lower latches as the other pilot was standing in the way. I walked over and secured the right side cowl; then returned to the left side and spoke with the other pilot who was standing in front of the left cowl. Just then my #2 aircraft started his engine; and in my hurry to get going I did not do my usual last chance inspection to ensure the aircraft was safe for flight.I am extremely disappointed to have missed such an important item. One contributing factor is my lack of recent flying experience; my plane has been out of service for several months; so I only logged X flight hours in the past 90 days. No excuse--interrupted checklists should be started over. I shouldn't have allowed an interruption of my safety duties. I shouldn't allow time pressure to affect my flows and checklists.