Date: 201812
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: IMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Final Approach
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Second reporter function: First Officer; Pilot Flying
Anomaly: Deviation - Speed All Types; Inflight Event / Encounter Unstabilized Approach; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Executed Go Around / Missed Approach; Flight Crew Took Evasive Action
Contributing factors: Weather; Human Factors
Primary problem: Weather

Narrative: Weather and thunderstorms were in the ZZZ area on our approach. We briefed and flew the ILS to XXR. On the approach; my FO (First Officer) got a little behind in configuring and I was late to prompt him to take different actions resulting in an unstable approach with the conditions we faced. I called for the go-around and my FO executed it appropriately. Tower gave us a left turn and climb to 2000 feet. As we leveled off; there was a bit of confusion with the MCP/autopilot as it wouldn't engage. As we discussed what was going on with the automation; the airspeed started an insidious decay. My FO started adding power to correct the decaying speed; but not quite fast enough. Then; very rapidly we apparently hit the outflow of one of the cells around us. We almost instantly lost 30 knots total around [recovery] speed. I took control of the aircraft when I saw 186 knots and falling; applied emergency thrust; and lowered the nose to get airspeed back. We kept the aircraft out of a stall; but as I got back to [recovery] speed and started to apply aft pressure on the yoke to level off/climb; tailwinds continued to increase and the stick shaker activated. Lessened the pressure on the yoke and gained more speed. We were able to initiate a climb at that time in heavy moderate turbulence. There was a cell in front of us and Approach gave us a 060 heading to avoid weather. With the turbulence and 50 knots or so tailwind it was a bit of a struggle to get the airplane to turn. Eventually; I started to reduce climb passing 7000 feet MSL. We leveled at 8000 feet after we got out of the rough air.


Second narrative: I was Pilot Flying on approach into ZZZ. We had set up and briefed the ILS to XXR. I was having difficulty getting the aircraft slowed down to final flap speed and we elected to do a go-around as we were not in a stabilized configuration for landing. The go-around was uneventful until we leveled at our missed approach altitude of 2000 feet. There was a moment of confusion as we worked out an automation issue and I noticed a slow decay of airspeed. I began adding power; but didn't recognize it as windshear at that time. We suddenly were hit with a massive loss of airspeed and immediately lost 30 knots or so. The Captain took control of the aircraft and we acknowledged it was a windshear event and he began appropriate recovery procedure. At some point in the procedure; we received the stick shaker. We were in bad weather for several more minutes until ATC was able to get us a vector clear.Had I recognized the windshear earlier and accomplished a windshear escape sooner; the aircraft would most likely have been in a better state and easier to recover.


Synopsis: B737-700 flight crew reported a loss of airspeed due to wind shear resulting in a momentary stick shaker activation.