Narrative:

During our descent; we noticed weather approaching the field. We were about 35-40 miles from the final approach fix. We sent dispatch a message asking for current radar picture for the airport. He said he couldn't tell too much if there was any weather on the field. After that we decided to continue the descent. As we approached the FAF; the controller asked if we had the field. The captain said he did and accepted the visual approach. We set 1800 ft in the MCP and descended down from 3300 ft. At this point we were on a 90 degree intercept course for final approach fix. The captain recommended a 45 degree intercept which would have us intercepting the course just passed the FAF. We started configuring with gear down and flaps 15; as we started intercepting the inbound course we entered into a heavy rain shower; also at the same time the aircraft was capturing 1700 altitude and leveling off. I ask[ed] for flaps 30 during this same time period. When the localizer captured I noticed the glide path went full scale deflection. Also the airspeed was bleeding off very fast. The autothrottle was still engaged and it was not increasing power for some reason. With the airspeed going below ref; I executed a go around. Even with max power the airspeed decreased even further to around 130. We got airspeed low at this time we descended to around 1650 ft before the aircraft started climbing. Even though we asked for multiple updates on the weather at the field we didn't get a clear picture from the controller or tower. They never reported gust; which gave us the impression of just heavy rain not a thunderstorm near the field or on the approach path. We requested a climb to 10;000 and got a vector of 260. We started setting up for another approach and landed successfully.

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Original NASA ASRS Text

Title: B737 First Officer reported entering a thunderstorm on final approach that resulted in a loss of airspeed and a go-around.

Narrative: During our descent; we noticed weather approaching the field. We were about 35-40 miles from the final approach fix. We sent dispatch a message asking for current radar picture for the airport. He said he couldn't tell too much if there was any weather on the field. After that we decided to continue the descent. As we approached the FAF; the controller asked if we had the field. The captain said he did and accepted the visual approach. We set 1800 ft in the MCP and descended down from 3300 ft. At this point we were on a 90 degree intercept course for final approach fix. The captain recommended a 45 degree intercept which would have us intercepting the course just passed the FAF. We started configuring with gear down and flaps 15; as we started intercepting the inbound course we entered into a heavy rain shower; also at the same time the aircraft was capturing 1700 altitude and leveling off. I ask[ed] for flaps 30 during this same time period. When the localizer captured I noticed the glide path went full scale deflection. Also the airspeed was bleeding off very fast. The autothrottle was still engaged and it was not increasing power for some reason. With the airspeed going below ref; I executed a go around. Even with max power the airspeed decreased even further to around 130. We got airspeed low at this time we descended to around 1650 ft before the aircraft started climbing. Even though we asked for multiple updates on the weather at the field we didn't get a clear picture from the controller or tower. They never reported gust; which gave us the impression of just heavy rain not a thunderstorm near the field or on the approach path. We requested a climb to 10;000 and got a vector of 260. We started setting up for another approach and landed successfully.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.