Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Workload
Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Aircraft Equipment Problem Dissipated
Human Factors
I was flying from ZZZ - ZZZ1. I was Pilot Monitoring and my First Officer was Pilot Flying. The weather at the time was heavy rain; 4 sm visibility; and overcast at 2;200 ft. At the time ZZZ was in a south flow and we were set up for Runway XXR. After we pushed back; ran the after start checklist and were ready to taxi; ground informed us that they were switching to a north flow and to expect Runway XYR; and stated the winds were '300 at 14 kts.' I stopped; re-entered the numbers in ACARS and the new numbers for Runway XYR were flaps 20 instead of flaps 8; which I promptly read out and pointed at. Somehow; however; the new flap position did not get selected. I then called for the runway change checklist; ran it; and began our taxi. Upon commencing the takeoff roll and passing through 80 knots; I was doing my scan of the instruments and noticed the flaps were still at 8 and not 20; so I selected 20. We got a 'config flaps' warning which promptly went away as soon as the flaps reached their newly commanded position so I continued the takeoff roll and lifted off without any issues.The reason I elected not to abort the takeoff was because we were in heavy rain and the aircraft only had one operable thrust reverser. Adding a 'flaps __' item in the before takeoff above the line checklist but the barriers that are currently in place have been sufficient numerous times before. I simply made a mistake that I have learned from and that will make me more vigilant and observant in my duties.
CRJ Captain reported that distraction and a runway change resulted in takeoff with an incorrect flap setting.