UK GAS-Prices mixed in oversupplied market

LONDON, Sept 26 (Reuters) - British gas prices were mixed on Thursday, with the day-ahead contract lifted by cooler weather forecasts and the within-day contract down on oversupply.

* The day-ahead contract was up 0.25 pence at 25.00 p/therm by 0830 GMT.

* "There looks to be a bit more demand on the weather (for day-ahead) but it's still fairly subdued," a gas trader said.

* Analysts at Refinitiv said temperatures were still expected to be mild for the rest of September but would be slightly cooler than previously forecast on Friday.

* Average day-ahead temperatures in Britain were seen at 13.3 degrees Celsius, Refinitiv Eikon data showed, down 1.6 degrees on the previous forecast.

* The within-day contract was down 0.53 p at 24.75 pence per therm.

* Britain's gas system was oversupplied by 3.7 million cubic metres (mcm) on Thursday with demand forecast at 157.6 mcm and flows at 161.3 mcm/day, National Grid data showed.

* Peak wind power generation is forecast at 8.6 gigawatts on Thursday and 8.2 GW on Friday, Exelon data showed.

* Six liquefied natural gas tankers are scheduled to arrive in Britain over the next month.

* Further out on the curve, prices were little changed.

* The winter 2019 contract was flat at 47.10 p/therm.

* The summer 2020 contract was down 0.10 p at 44.60 p/therm.

* The day-ahead gas price at the Dutch TTF hub was up 0.23 euro at 10.38 euros per megawatt hour.

* The benchmark Dec-19 EU carbon contract was down 0.04 euro at 25.20 euros per tonne. (Reporting by Susanna Twidale; Editing by Dale Hudson)