By weakening the US dollar the Fed managed to appease the main markets fears of 2016. Indeed, a weaker dollar reduces the pressure on China to further de-peg the Renminbi from the Greenback. It also provides a pause on the commodity slump, as these are quoted in dollars, which in turn raises inflation expectations.
The greenback may very well set the pace for equity markets over the coming weeks or months. A weaker dollar leading stock markets higher, and vice-versa. Hence, it will be important to keep an eye on the evolution of the dollar and the Fed.
The Dollar basket index (DXY) has been range trading between 100 and 93 since one yea, and lies now just above 95. A break below the lower band of the range @ 93, would send the greenback into a bear trend, which should help the current rally extend gains further. However a failure to do so would quickly bring back the clouds that held over our heads at the start of the year.
The SP500 currently trades close to the horizontal resistance @ 2050. Given the speed and intensity of the recent rally (1st overbought RSI since the index topped in the spring of 2015), it could be due for a short term correction towards 2000 as we enter into Easter thin volume period.