UK GAS-Prices weaken on oversupply

* System oversupplied by 23 mcm/day

* Strong gas injections to storage needed in Q3 -Energy Aspects

July 27 (Reuters) - British wholesale gas prices fell on Wednesday morning as higher supply nominations from Norway created oversupply.

Gas for day-ahead delivery was down 0.6 pence at 35.75 pence per therm by 0745 GMT, with the August contract falling 0.5 pence to 36.10 pence per therm.

"Tightness in the UK has changed today with strong Langeled (pipeline) flows generating significant oversupply and likely to weigh on prices for immediate delivery," said Oliver Sanderson, gas analyst at Thomson Reuters (Dusseldorf: TOC.DU - news) .

Demand was forecast to be 169 million cubic metres (mcm) and flows were around 192 mcm/day, meaning the system was 23 mcm oversupplied, National Grid (LSE: NG.L - news) data showed.

Supply through Norway's Langeled pipeline were nominated at 26 mcm, up 12 mcm on the previous day after several Norwegian outages ended overnight.

Suppliers have to notify the transmission system operator, or nominate, the amount of gas they want to put into the system on a particular day or later.

Demand for gas from the power sector is seen at 42 mcm/d over the next 15 days, from 50 mcm/d over the previous 15 days, with a drop in temperatures expected to reduce demand for air conditioning while wind output rises slightly, according to Thomson Reuters analyst forecasts.

Britain's storage sites are 55 percent full at around 2.4 billion cubic metres, data from Gas Infrastructure Europe showed.

"While the overall storage position looks better than last year, it would still require robust injections throughout the third quarter of 2016 to get back to a reasonable level by the start of October," said analysts at UK-based consultancy Energy Aspects.

The consultancy has revised its fourth-quarter price forecasts to 42 p/therm from 33 p/therm and its forecast for the first quarter of 2017 to 42 p/therm from a similar level due to expectations of a tighter market and a rise in coal prices to $65 a tonne.

In Europe's carbon market, front-year EU allowances edged up by 0.03 euros to 4.55 euros a tonne.

In the Netherlands, the August gas price at the TTF hub was down 0.12 euros at 14.40 euros per megawatt-hour. (Reporting by Nina Chestney; Editing by David Goodman)