UPDATE: MBTA General Manager Beverly Scott said this afternoon the authority will seek federal disaster aid and that it could be 30 days - yes, 30 - before the T is fully operational again, but only if we don't have another blizzard.
The MBTA says service on the T will be about the same as today, MassDOT says: The Red Line will run between Alewife and Andrew, the Orange Line between Sullivan and Back Bay and the Green Line between Lechmere and Kenmore, except for the D branch, which will continue all the way to Riverside. The Blue Line will run all the way between Bowdoin and Wonderland.
On the Red Line that's still running, trains will operate every six to seven minutes. On the discontinued segments of the Red Line, there'll be "limited substitute bus service" on the Ashmont and Braintree branches. Also limited bus replacement for the Mattapan Line.
Orange Line trains will run every 12 minutes, with limited bus service between Oak Grove and Sullivan and between Back Bay and Forest Hills.
Green Line trolleys will run every five or six minutes. Also:
Along the B branch, Route 57 buses will make stops between Packards Corner and Kenmore Stations. There will be no bus service between Packards Corner and Boston College.
Along the C branch, limited shuttle bus service will be available between Cleveland Circle and Kenmore.
Along the E branch, Route 39 buses will make stops between Northeastern and Heath St. Stations.
Buses, including the Silver Line, will run on weekday schedules, but expect delays.
Please note that parking in MBTA garages will continue to be permitted, but availability may be limited. Lynn, Beverly, Salem, and Wonderland Garages will continue to have low availability. Additional parking availability information can be found here. Illegally parked vehicles in garages that are found to be blocking pedestrian access ways and/or traffic lanes will be subject to towing. Passengers are encouraged to park in garages only when leaving their vehicle on the premises overnight.
MBTA passengers may also park in available Massport parking at Suffolk Downs Station and board Massport employee shuttles either to Airport terminals or to the Blue Line Airport Station.