UK GAS-Gas for immediate delivery up on undersupply

LONDON, May 11 (Reuters) - British gas for immediate delivery rose slightly on Thursday morning due to undersupply while other contracts dipped as warmer weather forecasts curbed demand. * Gas for immediate delivery rose by 0.35 pence to 40.25 p/therm at 0735 GMT. * Gas for day-ahead delivery was flat at 39.00 p/therm. * The gas system was undersupplied by around 8 million cubic metres (mcm), with flows at 190 mcm/day and demand at almost 198 mcm, National Grid (LSE: NG.L - news) data shows. * Thomson Reuters (Dusseldorf: TOC.DU - news) analysts expect the system to become tighter on Thursday due to production disruption at the UK Continental Shelf. * There are no flows into Bacton Shell, according to National Grid data. Shell (LSE: RDSB.L - news) was not immediately available to comment. * Flows from Norway through the Langeled pipeline are also lower at 15 mcm due to the full shutdown of the Ormen Lange gas field. * Milder temperatures are expected in Britain over the coming week which is curbing demand, traders said. * In the Dutch gas market, the day-ahead TTF gas price was down 0.18 euro at 15.77 euros per megawatt hour. * Benchmark Dec-17 EU carbon contract was up by 0.01 euro at 4.46 euros a tonne. * Thomson Reuters analyst view: http://emea1.apps.cp.extranet.thomsonreuters.biz/cms/?pageid=united-kingdom-gas (Reporting by Nina Chestney)