B737-800
Flight Crew Air Transport Pilot (ATP)
Situational Awareness; Other / Unknown; Workload
Deviation - Speed All Types; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Executed Go Around / Missed Approach; Flight Crew Exited Penetrated Airspace; Flight Crew Took Evasive Action
Weather
The weather was VFR with rain directly over the field and and the winds were favoring RW 25. I elected to practice the VNAV RW 25 and requested radar vector for this approach. I planed for this and briefed the RW 25 RNAV approach before the decent started. I was cleared to 2500' and leveled at 2500'. I was configured with flaps 5 and speed was set. I was given a heading of 270 degrees to intercept the final approach course about 6 miles from the (FAF) ZZZZZ and cleared for the RNAV 25. As the autopilot was intercepting the inbound heading of 249 degrees we experienced a 15 knot loss of indicated airspeed and moderate turbulence. I immediately disconnected the autopilot and the auto throttles and simultaneously rolled wings level and increased the throttles. I pitched up when I was confident that the airspeed was recovered to a safe speed. I asked the FO to inform the approach controller that we aborted the approach. We maintained the 260 degree heading and climbed up to 4000'. We flew out for approximately 10 miles. After 10 minutes we received radar vectors for a right base and a visual approach without incident.The wind sheer was much worse than expected and I have never experienced anything like that.I will elect to hold until the strong down drafts of the isolated rain showers dissipate of move out of the area.
B737-800 Captain reported wind shear and loss of air speed on approach.