Air carrier flight crew reported receiving a predictive wind shear warning passing 100 kts on the takeoff roll at IAD. They continued the takeoff because there were no secondary indications of wind shear.
Synopsis
Air carrier flight crew reported receiving a predictive wind shear warning passing 100 kts on the takeoff roll at IAD. They continued the takeoff because there were no secondary indications of wind shear.
Narrative
Clear skies; winds 340/3; temp -7. Deiced trace frost at the Gate. Good weather and no convective activity through local area. We departed Runway 30 and passing approximately 100 kts. there was a predictive wind shear warning. After a quick mental assessment of local conditions and the possibility of a high speed abort I opted to continue. We had no secondary indications; no fluctuations in airspeed or reports from the recently departed air carrier in front of us. During departure we experienced no anomalies.I've done two go-arounds over the last few weeks (one for low weather and one for an unstable approach) and experienced the same operational stresses that everyone else has recently but this was one of my toughest decisions in recent memory. I know what the manual says regarding predictive windshear guidance but the FO (First Officer) and I debriefed out of 10;000 feet and we were both in agreement that under the circumstances; with the conditions we were encountering; that continuing was the best course of action.
Second reporter narrative
During takeoff roll above 80 kts. (I believe around 100 kts.) we had a predictive wind shear alert. Due to the current weather conditions we believed this message appeared to be an anomaly. The weather was clear skies; temp -7; calm winds (130/4) and no convective activity. Neither the previous aircraft that took off right in front of us nor Tower mentioned any wind shear conditions. Our takeoff was normal and we did not encounter any wind shear; airspeed fluctuations or turbulence.After re-reading the FOM; [Flight Handbook] and Ship Handbook regarding wind shear; I will now be more assertive stating the wind shear alert; possibly with an abort or go-around depending on the situation. It's best to always error on the side of safety.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.