We're About To Find Out If China's Economy Is Actually Slowing Down Again

Economists polled by Bloomberg are looking for flash PMI to rise to 50.8 in March, from 50.4 the previous month.

Official PMI fell to 50.1 in February. Remember, a reading below 50 indicates contraction.

Meanwhile, industrial production increased 9.9 percent in the Jan-Feb period, compared with a 10.3 percent rise in December.

The slowdown in manufacturing is part of the reason investors are getting anxious about a Chinese hard landing again. A Bank of America survey of global investors showed that those expecting strong growth fell to 14 percent in March, from 60 percent.

Now BAML's Ting Lu has lowered his GDP forecasts.

"With the recent weak IP growth, the brought-forward property tightening measures, the new leaders’ serious crackdown on government’s luxury consumption, the demand for much tougher stance on environment protection and the worsening situation in Europe, we cut forecast of China’s annual GDP," he writes.

Lu expects Q1 and Q2 growth to come in at 7.9 percent and 8.1 percent, down from earlier estimates of 8.3 percent for both quarters respectively. For 2013, he expects growth of 8 percent, down from 8.1 percent.

"We believe markets now are a bit too bullish and we expect consensus forecast to be trimmed in coming weeks," Lu writes.

He expects consensus estimates of 8.2 percent growth in 2013, and 8.0 percent growth in 2014 to be revised down. He also sees "relatively strong headwinds" for stocks and commodities.

While previous data was taken with a grain of salt because of the impact of the New Year, the March PMI numbers should give a clearer picture of manufacturing and a broader picture of economic growth.