Narrative:

Myself and another pilot had made the flight on an IFR flight plan. On the way up to kansas; thunderstorms were to the west of us; but we flew east of them without any issue. Upon arriving in kansas; we picked up another pilot who was also instrument rated; and he and I flew in the front seats on the way back; with the previous pilot sitting in the backseat. We flew VFR to an airport in northern oklahoma without issue; where we fueled the airplane. We then filed an IFR flight plan and continued our trip back home. The initial line of thunderstorms had passed through to the east of our route; but another line was building over oklahoma city. We deviated several times to avoid areas of moderate and heavy precipitation by using ATC suggestions and xm weather (nexrad). After successfully navigating the storms for some time; we were passed to fort worth center. We requested a few deviations to the right by using the xm radar in order to go around the building storms on the back side. At this time; it had been at least 30 minutes since we had received an advisory from ATC for moderate to heavy precipitation. We had found a gap in the storms that was showing on our xm radar to be green and yellow areas. After 10 minutes or so in this area; the radar updated and showed us rapidly approaching a pink area of extreme precipitation. Unable to avoid it quickly enough; we flew into the precipitation and experienced extreme precipitation; severe turbulence; light hail (pea sized at most); and heavy downdrafts. After flying in the extreme precipitation for 20 seconds or so; we experienced a momentary loss of power which we expect to be due to the ingestion of water in the engine intake. We informed ATC that we were experiencing 'engine troubles' and severe turbulence; and got radar vectors out of the storm. After exiting the precipitation; the engine power resumed and we continued the flight without issue.

Related reports:

Google
 

Original NASA ASRS Text

Title: C172 pilot reported entering an area of extreme precipitation and severe turbulence while using NEXRAD XM weather to circumnavigate storm areas.

Narrative: Myself and another pilot had made the flight on an IFR flight plan. On the way up to Kansas; thunderstorms were to the west of us; but we flew east of them without any issue. Upon arriving in Kansas; we picked up another pilot who was also instrument rated; and he and I flew in the front seats on the way back; with the previous pilot sitting in the backseat. We flew VFR to an airport in northern Oklahoma without issue; where we fueled the airplane. We then filed an IFR flight plan and continued our trip back home. The initial line of thunderstorms had passed through to the east of our route; but another line was building over Oklahoma City. We deviated several times to avoid areas of moderate and heavy precipitation by using ATC suggestions and XM weather (NEXRAD). After successfully navigating the storms for some time; we were passed to Fort Worth Center. We requested a few deviations to the right by using the XM radar in order to go around the building storms on the back side. At this time; it had been at least 30 minutes since we had received an advisory from ATC for moderate to heavy precipitation. We had found a gap in the storms that was showing on our XM radar to be green and yellow areas. After 10 minutes or so in this area; the radar updated and showed us rapidly approaching a pink area of extreme precipitation. Unable to avoid it quickly enough; we flew into the precipitation and experienced extreme precipitation; severe turbulence; light hail (pea sized at most); and heavy downdrafts. After flying in the extreme precipitation for 20 seconds or so; we experienced a momentary loss of power which we expect to be due to the ingestion of water in the engine intake. We informed ATC that we were experiencing 'engine troubles' and severe turbulence; and got radar vectors out of the storm. After exiting the precipitation; the engine power resumed and we continued the flight without issue.

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.