UK GAS-Within-day prices ease as domestic supplies rise

* Imports from Norway falls by around 10 mcm/day

* UK domestic output close to maximum winter levels

March 24 (Reuters) - British gas prices for within-day delivery eased slightly on Thursday morning as a rise in domestic production offset a fall in Norwegian gas imports.

Gas for immediate delivery fell 0.05 pence to 29.10 pence per therm by around 1015 GMT.

Britain's gas system was broadly balanced on Thursday morning with demand forecast at 280 mcm per day, National Grid (LSE: NG.L - news) data showed.

Imports from Norway fell by around 10 mcm due to a drop in flows through the Langeled pipeline, Britain's main gas import artery.

This was offset by higher domestic supplies from the UK's continental shelf, partly due to an increase in flows at St Fergus Mobil terminal.

"Today's levels are probably close to the maximum observed UKCS production this winter, which is around 110 mcm once Norwegian gas (deliveries via Vesterled and FLAGS pipelines) is excluded," analysts at Thomson Reuters (Dusseldorf: TOC.DU - news) said.

Deliveries from Britain's LNG terminals were nominated at around 37 mcm/day as one tanker, Al Hamla, docked at South Hook terminal. Two new tankers are confirmed to arrive on March 28 and March 31.

Day-ahead contract for delivery next Tuesday gained 0.15 pence or 0.52 percent 29.25 pence/therm due to colder weather outlook.

Next (Other OTC: NXGPF - news) week is expected to start with temperatures near or slightly below normal levels and strong winds in western and southern areas, Britain's Met Office said.

Further along the curve, contract for gas delivery next-season was trading 0.13 pence up at 27.85 pence/therm.

Dutch day-ahead gas prices remained unchanged to 12.05 euro/MWh.

In the European carbon market, front-year allowances eased 0.04 euro or 0.83 percent to 4.77 euro a tonne. (Reporting by Nerijus Adomaitis; editing by Susan Thomas)