A marked upper tropospheric temperature anomaly observed by an aircraft near a thunderstorm over inland Western Australia

A marked positive temperature anomaly of up to 18°C was encountered by a commercial passenger aircraft near Meekatharra, Western Australia at an altitude of around 9500 m. The aircraft was diverting around the up-wind side of a large thunderstorm at the time and experienced difficulties maintaining power. The meteorological aspects of the situation are examined and evidence is presented that similar anomalies have been observed at other times, in other parts of the world. Adiabatic warming of air returning from the stratosphere as a result of interactions between the thunderstorm outflow and the environmental airflow is shown to be consistent with the magnitude of the anomaly observed.