UK GAS-Prompt prices steady on ample supplies

* System 10 mcm long -National Grid (LSE: NG.L - news)

* Outages impact flows from Norway

Oct (HKSE: 3366-OL.HK - news) 27 (Reuters) - British gas prices were steady on Tuesday capped by ample supplies and mild weather which weakened demand.

Gas for within day delivery eased 0.25 pence per therm to 38.85 pence per therm by 0921 GMT, while day-ahead prices firmed 0.03 pence to 38.75 pence.

The system was 10 million cubic metres (mcm) long with forecast daily demand pegged at 225 mcm per day, while supply was at 235 mcm.

Outages impacting flows from Norway's Troll and Kvitebjoern fields helped support the market.

"The long system and healthy supply outlook could see contracts soften as the day progresses, especially if the current Norwegian issues are resolved in line with estimates," said Marcel Boonaert, head of trading and portfolio at Wingas UK.

Temperatures were expected to remain above seasonal norms over the coming weak, softening demand for gas for heating.

Gas prices for December rose 0.28 pence to 40.20 pence/therm.

"Monthly contracts have also ticked higher, potentially taking direction from increased gas to power demand though this is likely being tempered by the strong outlook for LNG supplies through the balance of the year," said Wingas' Boonaert.

Two LNG tankers were added to the expected arrivals in the UK on Tuesday with the Al Samriya due on Nov. 3 and the Tembek on Nov. 6.

In the Netherlands, the day-ahead gas price at the TTF hub was up 0.28 euros to 18.18 euros per megawatt hour.

In Europe's carbon market, the benchmark EU Allowance (EUA) edged down 0.02 euros to 8.64 euros a tonne. (Reporting by Sarah McFarlane; editing by Jason Neely)