UK GAS-Prompt mostly down on milder weather outlook

* Day-ahead down 0.20 pence at 30.00 p/therm

* Temperatures expected to increase by end of week

* Within-day up on undersupply, increased demand

LONDON, March 7 (Reuters) - British wholesale gas traded mixed on Monday morning, as prompt prices declined on expectations of milder temperatures and increased supply towards the end of this week while the curve mostly rose on oil price gains.

Gas for day-ahead delivery was down 0.20 pence per therm at 30.00 p/therm at 0935 GMT from the previous settlement on Friday.

Gas for immediate delivery inched up by 0.05 p to 30.00 p/therm, lifted by an undersupplied gas system and higher demand.

Britain's gas network was short by almost 26 million cubic metres (mcm). Demand was forecast at nearly 330 mcm/day - 61 mcm above the seasonal norm - and flows at around 304 mcm/day, National Grid (LSE: NG.L - news) data showed.

Demand for gas for heating received a boost from below-normal temperatures, analysts said, but temperatures were expected to rise to above normal by the weekend.

On the supply side, flows from Norway through the Langeled pipeline are strong at around 72 mcm and expected to remain sizeable in the coming days.

Supply from the Netherlands through the BBL pipeline is close to 30 mcm and is expected to stay close to this level until the current cold snap ends.

Further along the curve, the UK winter 2016 gas contract was 0.17 p higher at 33.20 p/therm, supported by rising oil prices.

In the Dutch gas market, day-ahead prices at the TTF hub inched up by 0.02 euro to 12.30 euros per megawatt-hour.

Front-month Brent crude oil futures extended a rally on Monday morning to around $39.15 a barrel. The contract is now a third higher than its January low, when prices fell to levels not seen since 2003.

"This (higher oil price) is a strong bullish driver and should lift the curve irrespective of bearish fundamentals," said Oliver Sanderson, Thomson Reuters (Dusseldorf: TOC.DU - news) gas analyst.

The day-ahead TTF price declined on Friday due to forecasts for higher-than-normal temperatures in the second half of March and relatively low gas consumption.

In the European carbon market, front-year allowances edged up by 0.05 euro to 4.98 euros a tonne. (Reporting by Nina Chestney; Editing by Dale Hudson)