Economists estimate that the index rose to 6.8 in August from 5.7 last month, according to Bloomberg.
This index is expected to provide a more complete picture of manufacturing in the northeast, after the Empire State manufacturing survey index plunged to the lowest level since 2009 on Monday.
In a preview to clients, UBS' Sam Coffin wrote: "Details of the Philadelphia Fed survey were even softer than the headline index in July. The headline index, which is based on a single, stand-alone question about general business conditions, fell to 5.7 from 15.2; however, our ISM-equivalent series, which aggregates other details of the survey, fell almost to its 50 break-even level. We project reacceleration in August, as the national ISM index has not appeared as weak."