US GDP data has been distorted to an unprecedented degree by trade uncertainty. Kevin Gordon of @CharlesSchwab points out that net exports took the biggest bite of GDP in history in Q1, then made a record contribution to GDP in Q2.

It's understandably been increasingly difficult to forecast how the data will come in. Citi's Economic Surprise index has whipsawed from deeply negative at the end of June to one of the most positive levels this year.