UK GAS-Prices mixed: oversupply weighs but cooler temperatures ahead

(Refiles to fix paragraph order)

* Slight oversupply weighs on gas for immediate delivery

* Cooler temperature forecast for next week supports prices

* Winter 2015 contract slides closer to record low

LONDON, May 27 (Reuters) - British prompt gas prices were mixed on Wednesday morning with gas for immediate delivery declining on oversupply and other prompt contracts higher on cooler temperature forecasts for next week.

The within-day gas price fell by 0.25 pence to 42.85 pence per therm at 0759 GMT.

National Grid (LSE: NG.L - news) data showed demand was forecast at around 203 million cubic metres (mcm) on Wednesday and supply at 209.6 mcm/day, indicating the system was oversupplied by 6.5 mcm/day.

Gas flows from the UK Continental Shelf are slightly higher and exports to Europe lower than on Tuesday.

Liquefied natural gas supply is also healthy with three tankers expected to come to Britain over the next few days.

However, flows through the Langeled pipeline from Norway have dropped to 9 mcm from 18 mcm on Tuesday, likely due to an ongoing outage at the Kvitebjørn field, a UK gas trader said.

The winter gas contract for 2015 was down 0.45 pence at 47.70 p/therm, edging closer to a record low of 47.45 p/therm.

Meanwhile, gas for delivery on Thursday inched up by 0.05 pence to 42.95 pence per therm, while June gas was up 0.10 pence at 41.75 p/therm.

Traders said cooler temperatures were forecast for next week which would raise gas demand and wind power generation had fallen, which was supporting prices.

Consultancy Energy Aspects also said it saw support for prompt contracts above 42 p/therm as many utilities would switch from coal to gas for power generation, also lifting gas demand.

In the Netherlands, the June gas price at the TTF hub flat at 20.48 euros per megawatt hour.

Traders are also awaiting a ruling by a Dutch court by June 1 at the latest on production restrictions at the Eemskanaal gas field cluster in the Groningen region, which accounts for around 2 billion cubic metres (bcm) a year of Dutch production, or 5 percent of the Groningen region's total last year.

"We do not think the ruling will have that much bearing on Groningen production as it is just on one specific part of the field," Sikorski said.

"More important will be the July 1 announcement by the Dutch government on the cap for the second half of the year for all of Groningen. We expect that this will see no increase on the 16.5 bcm cap that was put in place for the first half of the year."

The benchmark European Union carbon price was trading 0.03 euros lower at 7.23 euros a tonne. (Reporting by Nina Chestney; editing by Jason Neely)