The Markit Flash U.S. Manufacturing Purchasing Managers' Index (PMI) fell a seasonally adjusted 0.6% to 52.8 for September, according to a Markit report (link opens as PDF) released today.

The "flash" estimate is typically based on approximately 85% to 90% of total PMI survey responses each month and is designed to provide an accurate advance indication of the final PMI data. An above-50 reading denotes general growth, while below 50 signals contraction.

Although this month's report continues to point to modest expansion, its 52.8 reading is the lowest in three months. After August's final 53.1 rating, analysts had expected September to bring bigger growth, but their 54.0 estimate proved too optimistic. 

Diving deeper into components, new orders took a three-point dip to 52.7, its slowest rate since April. New export orders fell into the red at 49.1, while employment growth slowed from 53.1 to 51.4 for September. As a positive point amid mostly uninspiring numbers, output managed a solid 2.8-point bump to 55.3. 

"The flash PMI indicates that manufacturers enjoyed a further improvement in business conditions in September, suggesting the third quarter has on the whole seen stronger growth than the lackluster performance seen in the second quarter," said Markit Chief Economist Chris Williamson in a statement today. "However, as far as policymakers are concerned there are some worrying signals in relation to the sector's growth momentum, which vindicate the Fed's decision to hold off on tapering its asset purchases."