It’s a repeat of last weekend as post-Sandy repair work continues in the 4/5 and A/C tunnels under the East River. From 11:45 PM Friday, May 19 to 5:00 AM Monday, May 22 there will be no service in either direction at the 4/5 platforms at Borough Hall. Also, after a reprieve, during this same time A and C trains are being diverted to the F line between Jay Street-Metro Tech and West 4th Street, so no service in either direction at High Street. Your options are to use the 2 or 3 to or from Clark Street or Borough Hall, the R or (late night) N to or from Court Street, or the A, C, or F to or from Jay Street in Downtown or York Street in DUMBO. All of these should be running normally, barring the unforeseen.
The following work week, Monday, May 22 to Friday, May 26, each night from 11:45 PM to 5:00 AM, there will be no service to Manhattan from High Street, though there will be service from Manhattan to there. During those late night hours, Manhattan bound A trains will be diverted to the F line, and C trains do not run late at night. All other lines should be running normally.
For planned service changes that may affect travel on other parts of the system, either during the weekend or the following week, see MTA Info or The Weekender.