US growth is expected at 2.9% on average in 2018. This corresponds to a growth rate of 0.7/0.8% in Q4 (non-annualized figures). This view is consensual, as is the consensual perceived robustness of the economy and the slowdown to an average growth of 2.5% in 2019.
Making all of these elements compatible is interesting.
If the 2.9% of 2018 is ok (with 0.8% in Q4), it is necessary to think about 2019.
The average quarterly growth rate needed to converge to 2.5% is 0.5% (non annualized) The slowdown in the US economy is strong from the very beginning of the year. This figure must be compared to 0.8% which is the average quarterly growth in 2018.
The assumption of maintaining robust growth in the first half of 2019 (0.8% per quarter) implies a rapid decline from the summer. Convergence to 2.5% implies a contraction of -0.2% per quarter from the summer.
If growth is robust at the beginning of 2019, then to be compatible with the consensus forecasts, it will take a break from the summer