* May light synthetic quoted at $10/bbl above WTI
* Suncor, Canadian Natural gear up for oil sands maintenance
* WCS for May $12.75/bbl under WTI
CALGARY, Alberta, April 4 (Reuters) - Canadian light synthetic crude prices rose on Thursday as the market prepared for scheduled outages at major northern Alberta oil sands operations.
Light synthetic for May delivery last sold for $10 a barrel over benchmark West Texas Intermediate, up 10 cents from Wednesday's settlement, according to Shorcan Energy Brokers.
Supplies will be tight in the coming weeks as such oil sands operators as Suncor Energy Inc and Canadian Natural Resources Ltd start major maintenance at their facilities.
Suncor is poised to start seven weeks of planned maintenance on the 100,000 barrel per day Upgrader 1 unit at its site north of Fort McMurray, Alberta. The overall oil sands operation has a capacity of about 350,000 bpd.
Canadian Natural has said its 115,000 bpd Horizon oil sands plant will be down for 18 days in May for a turnaround, though that could stretch to 24 days, according to TD Securities.
Supplies of upgraded light synthetic have tightened in recent weeks as another major operation, Syncrude Canada Ltd, has been running well under capacity.
Canadian Oil Sands Ltd, the Syncrude joint venture's biggest interest owner, said this week the facility produced 261,000 barrels a day in March, up 9 percent from February but still well under the facility's 350,000 bpd capacity.
Meanwhile, Western Canada Select heavy blend for May was quoted at $12.75 a barrel under WTI, compared with a settlement of $13.55 a barrel on Wednesday. That was its smallest discount since Oct. 3.
Part of the recent strength in Canadian heavies - WCS fetched $40 a barrel less than WTI in January - has been the slow start-up of the first phase of Imperial Oil Ltd's 110,000 Kearl oil sands project. That has kept previously anticipated volumes out of the market, industry sources have said.
Imperial said early this week it expected to start producing marketable diluted bitumen from the C$12.9 billion ($12.69 billion) project in "the next few days."