The Philly Fed manufacturing index came in at 4.7 for May, leaping into positive territory from the prior month.
Economists had forecast that the diffusion index for current activity rose to 1 after tumbling to -1.8 last month, according to Bloomberg.
This is just the third time in the past year that the index has been positive.
Overall, the report called the recovery in the manufacturing "tepid" and cited some worrying underlying trends below the headline number. For labor, hours worked and the employment index remained negative, falling to -10.9 from -3.3 in May.
The report also noted weakness in the growth of new orders and shipments. Additionally, the index measuring prices paid by manufacturers rose for the fourth straight month to 23.0, from 16.0 in May.
Encouragingly, however, long-term outlook for businesses in the region stayed positive with 46% of firms expecting a pick-up in activity over the next 12 months, against just 16% expecting a decline.
The bounce back comes as another strong reading for regional manufacturing, after the Empire State Manufacturing Index showed an unexpected spike for industrial activity Monday.