Date: 201909
Local time of day: 0601-1200
Location: ZZZZ.Airport, FO
Flight conditions: IMC
Weather elements / visibility: Rain; Thunderstorm
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
ATC / advisory: Tower ZZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Workload; Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Provided Assistance; Flight Crew Executed Go Around / Missed Approach; Flight Crew Diverted; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Weather
Primary problem: Weather

Narrative: This report details a wind shear event on approach that led to a diversion.During approach; there was a strong rain shower (radar returns stronger than rain only but contours less defined than a thunderstorm) between the final approach fix and Runway 12L threshold. Rain was visible out the bottom of the cloud. Other airplanes were getting in (although I'm not sure of the name or type of the planes). Given its relative strength from radar returns on minimum gain settings; we decided to try an approach. The First Officer was the pilot flying. Prior to entering the rain shower; I flipped the start switches to FLT. The First Officer vocalized the potential need for me to turn on windshield wipers once we cleared the cell. Shortly after entering the heavy rain; at roughly 1;000-1;500 feet. AGL; a wind shear alert was heard. I do not recall which alert it was with 100% certainty; however; I believe it was 'Wind shear Wind shear.'I announced; 'Wind shear! Set max thrust. Stow speed brake.' The First Officer responded properly. I then informed Tower that we were going around. We quickly left the wind shear threat zone; however; I should have vocalized this to the First Officer. Concurrently; the First Officer started the go-around callouts. When it came time for retracting the flaps; I was overloaded with radio calls; monitoring the First Officer's flying (which included slightly higher pitch attitudes than were called for by the flight directors during the wind shear event). The First Officer; in an effort to continue cleaning up the aircraft; moved the flap lever himself from 5 to 1 to up. We [later] debriefed the importance of not changing the configuration of the aircraft without proper communication with other crewmembers.The First Officer used heading select to get back onto the LNAV missed approach path; which resulted in slight lateral course deviations until back in LNAV.We held as published for 15 minutes or so. During that time; we coordinated with passengers; flight attendants; and Dispatch to create a plan. After another aircraft went around on approach; we decided a diversion was most prudent given how slowly the storm was moving away from the field.After informing dispatch and ATC; our flight proceeded and successfully flew the RNP approach to Runway 30 in visual conditions. Roughly 1 hour later; our flight was fueled and ready to depart. The return flight was completed without event.


Second narrative: [Report narrative contained no additional information.]


Synopsis: B737 flight crew reported encountering wind shear; resulting in a diversion.