Date: 201601
Local time of day: 1801-2400
Location: IAH.Airport, TX
Flight conditions: IMC
Weather elements / visibility: Rain; Thunderstorm
Aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Final Approach
Airspace: Class B IAH
ATC / advisory: Tower IAH
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Situational Awareness; Workload; Distraction
Second reporter function: First Officer; Pilot Not Flying
Anomaly: ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Automation Aircraft Other Automation
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Executed Go Around / Missed Approach; Flight Crew FLC complied w / Automation / Advisory
Contributing factors: Weather
Primary problem: Weather

Narrative: We were on final for runway 8R in IAH and encountered windshear.  We intercepted final approximately 30 miles out and were instructed to slow continuously all the way back to 160 knots.  I was the pilot flying and we lowered the gear and were fully configured at 20 miles from IAH; auto pilot on.  Tower started calling an approach wind loss of 20 knots that increased to 25 knots at a 3 mile final.  The copilot and I were discussing what constituted a microburst alert which was 30 knots so we elected to continue the approach.  We were in moderate turbulence and the wind was currently a right quartering tailwind which would switch to a left crosswind on the runway.  I asked the copilot to increase our target speed to plus 20 which he did and as we approached the outer market we were fully configured and on speed.  At approximately 1;400 feet AGL we received a 'monitor radar display'.  I saw the indication was ahead of us to the right of our course.  Since we were still stable; fully configured and autopilot and autothrottle on; we elected to continue.  Shortly after we received the call 'go around; windshear ahead'.  I initiated the go around and asked for flaps 15 and gear up.  Very shortly after this we received the call 'WINDSHEAR; WINDSHEAR; WINDSHEAR'.  At that point I pushed the throttles to the stops and verified the spoilers were stowed and selected Takeoff Go Around (TOGA) again.  The first officer called ATC and said we were going around and I was so focused on flying the plane with regards to RA and trend and verifying I was doing everything correctly; I did not hear what ATC replied back to us.  Adding to the workload and task saturation was the plane on 8L also went around and then the two planes behind us on 8R and 8L also went around.  The copilot drew my attention that ATC said to level off at 2;000 feet as we were passing through 2;000 with a high climb rate.  I still had WINDSHEAR displayed on my ADI and I told him I was not going to level off.  He then had to try to talk to ATC again to get a new altitude which they did give us of 3;000 feet.  We were climbing rapidly and I brought the throttles back to level off at 3;000 but overshot it to approximately 3;200 feet and descended back to 3;000.  The landing gear horn immediately began to sound when I pulled the power back since we still had flaps 15.  I made sure we were above F15 retraction speed and we completed a normal go around at that point to clean maneuvering speed.  I do not believe we made many mistakes; I just wanted to bring this to your attention in that we are used to getting windshear training at a low altitude; heavy gross weight and normally on a hot day.  Granted; I would take my event over that situation any day but it posed a different kind of threat in that everything happened so fast and ATC should not give a level off altitude of 2;000 feet since I now know it is possible to still be in windshear (or at least have it displayed) at that altitude.  If I were to fly this approach again; I would elect to abort the approach and wait for tower to stop calling a 20-25 knot loss at a 3 mile final.  I did consider this option and vocalized to the co-pilot but we thought since the planes ahead of us were landing we would be able to.  Obviously there is always a first flight that cannot land and on this day; that was us.


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


Synopsis: A flight crew reported encountering windshear conditions on final approach and performed a go-around. The missed approach maneuver was successfully accomplished; however dynamic flight conditions resulted in a deviation from their assigned altitude.