we often use heat to describe an economy - 'hot' meaning really good, or 'on the boil' ... lukewarm or tepid means slightly warm, but not cool. Describing economy it means still growing, but not fast. In the context of China where growth has been at 8-10% it will still mean something like 5% and that is pretty good compared with Europe. The fundamentals of an economy would refer to quantitative measures like (un)employment, balance of trade, inflation, interest rate. In a pattern means there is a repeating behaviour each year. Hit a slowdown = the rate of economic growth slows or cools down (goes from hot to lukewarm to cool)