The progression of priority datesin the recent few months has been exciting news for many, especially those EB-3applicants who have been patiently waiting for their green cards for manyyears. 
Unfortunately the unexpected progressionhas swamped the National Visa Center. The NVC is now issuing letters indicating that NVC cases will be delayedfor 60 days.  Here is an excerpt from astock form letter that our office has received in the last few days.  We have received about a dozen of theseletters.
Weare currently receiving an increased number of approved petitions from U.S.Citizenship and Immigration Services. As a result, we are experiencingincreased review times for documents received.
Weexpect it will be at least 60 days from the date we received your mail beforewe complete the review of your documents. We will notify you when we reviewyour documents.
Weare working to reduce these processing times and we appreciate your patience.