There has been record warmth in and around the north pole this summer. This makes lightning much more likely at high latitudes. There's been an unusually strong and persistent blocking high pressure system just south of Alaska that's caused the northern branch of the polar jet to deviate north of the Pacific Ocean. This has meant a very warm, dry, and sunny summer for most of southern Alaska. The tendency for a trough to form downstream of the ridge near Alaska has meant more northerly flow over Canada. Persistent cooler northerly flow over Canada has meant the lack of any significant heat wave over the US this summer, outside the far southwest at least. Europe and Asia have experienced several significant heat waves this summer though. The northern hemisphere average this summer is in record warm territory, despite mostly average temperatures over North America.
11 Aug 2019, 9:46 pm
