Narrative:

When getting ready to depart; a thunderstorm was passing west to east about 10 miles north of the field. Due to rapidly changing winds; our runway was changed three times. After the second time we were told to wait in holding pad 1 while waiting for the storm to pass. ATC had then informed all aircraft that they were going to hold all departures for an estimated 30 minutes while they waited for the storm to completely pass. About 5 minutes later they advised us that winds were steady from the north and we could depart 7L with a gap that had formed. Looking at the radar; there was more than enough room to depart east and our departure turned us south (away from the cell) and then west (about 20 mile south of the cell). After discussing with the first officer; we decide that based on the radar; communication with ATC; other aircraft departing in the same direction; and seeing landing traffic; we decide it's safe to depart as offered. We make the needed changes for a 7L departure and run the runway change checklist and then before takeoff checklist. Once on tower we are advised 'winds are 360/25g34; can you accept that?' it was within limitations so we accept the takeoff clearance. Initial climb was normal and uneventful. About 5 miles off the runway departure advises us moderate to extreme precipitation 11 miles east of our position and that they could turn us south as we got higher. (10 east of the airport) we execute a turn to the south as published. At that time we hit what we thought was moderate to severe turbulence and the aircraft; with autopilot engaged; went from a 30 degree banked turn to a 45 degree banked turn for a few seconds. The attitude recovered quickly and we continued to experience moderate turbulence. The flight attendants and passengers were previously told to remain in their seats and double check that seatbelts were securely fastened. We continued the climb uneventfully to the west. Once out of sterile I called the flight attendants to make sure everyone was ok; which everyone was. We continued to [our destination] as normal and landed. At the gate I called [maintenance] to discuss the turbulence. We looked through the turbulence guidelines together. Based on the aircraft never being out of control; airspeed did not have any abnormal variations for moderate turbulence; and not being violently forced against seat belts (confirmed with the first officer and flight attendant) we decided that the turbulence was on the high end of the moderate category and a maintenance write up was not required. The first officer also made a thorough post-flight and did not note any abnormalities. This was my first experience with a thunderstorm near the terminal area. Based on sops (not departing/landing with thunderstorms within 5 miles of the airport; and remaining 20 miles away unless the crew determines they can safely navigate closer) we determined it safe. In the end I think it would have been a safer decision to delay until the storm was further away. Remember that radar images are not 'live' and just because other aircraft are departing and landing does not necessarily mean it is safe to do so. While the flight was safe; things could have been different with unpredictable weather or had a microburst occurred. This was a big lesson learned and decision-making will definitely be better around thunderstorms in the future.

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Original NASA ASRS Text

Title: EMB175 Captain reported severe turbulence associated with a thunderstorm on departure. During a 30 degree banked turn with the autopilot engaged the aircraft momentarily rolled to 45 degrees before recovering. Flight continued to destination.

Narrative: When getting ready to depart; a thunderstorm was passing West to East about 10 miles North of the field. Due to rapidly changing winds; our runway was changed three times. After the second time we were told to wait in holding pad 1 while waiting for the storm to pass. ATC had then informed all aircraft that they were going to hold all departures for an estimated 30 minutes while they waited for the storm to completely pass. About 5 minutes later they advised us that winds were steady from the north and we could depart 7L with a gap that had formed. Looking at the radar; there was more than enough room to depart East and our departure turned us South (away from the cell) and then West (about 20 mile South of the cell). After discussing with the FO; we decide that based on the radar; communication with ATC; other aircraft departing in the same direction; and seeing landing traffic; we decide it's safe to depart as offered. We make the needed changes for a 7L departure and run the runway change checklist and then before takeoff checklist. Once on tower we are advised 'winds are 360/25G34; can you accept that?' It was within limitations so we accept the takeoff clearance. Initial climb was normal and uneventful. About 5 miles off the runway departure advises us moderate to extreme precipitation 11 miles east of our position and that they could turn us south as we got higher. (10 east of the airport) we execute a turn to the south as published. At that time we hit what we thought was moderate to severe turbulence and the aircraft; with autopilot engaged; went from a 30 degree banked turn to a 45 degree banked turn for a few seconds. The attitude recovered quickly and we continued to experience moderate turbulence. The flight attendants and passengers were previously told to remain in their seats and double check that seatbelts were securely fastened. We continued the climb uneventfully to the West. Once out of sterile I called the flight attendants to make sure everyone was OK; which everyone was. We continued to [our destination] as normal and landed. At the gate I called [maintenance] to discuss the turbulence. We looked through the turbulence guidelines together. Based on the aircraft never being out of control; airspeed did not have any abnormal variations for moderate turbulence; and not being violently forced against seat belts (confirmed with the First Officer and Flight Attendant) we decided that the turbulence was on the high end of the moderate category and a maintenance write up was not required. The FO also made a thorough post-flight and did not note any abnormalities. This was my first experience with a thunderstorm near the terminal area. Based on SOPs (not departing/landing with thunderstorms within 5 miles of the airport; and remaining 20 miles away unless the crew determines they can safely navigate closer) we determined it safe. In the end I think it would have been a safer decision to delay until the storm was further away. Remember that radar images are not 'live' and just because other aircraft are departing and landing does not necessarily mean it is safe to do so. While the flight was safe; things could have been different with unpredictable weather or had a microburst occurred. This was a big lesson learned and decision-making will definitely be better around thunderstorms in the future.

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.