UK GAS-Prices fall on healthy supply, warmer weather

* Spot down 1 pct, further out contracts also slip

* System seen oversupplied by 14 mcm on Friday -NatGrid

* Average temperatures to stay elevated next week

* Disrupted Norway flows, Ukraine could support prices

LONDON, Aug 29 (Reuters) - Natural gas prices in Britain dropped on Friday on a healthier supply outlook and as warmer weather was forecast to remain for at least another week.

The day-ahead contract dropped 1 percent to 44.65 pence per therm. Further out, front-month and winter 2014 prices eased by 0.4 percent and 0.7 percent respectively.

Britain's gas system was forecast to be long by about 14 million cubic metres (mcm) on Friday, according to National Grid.

Imports from Europe via the Langeled and BBL pipelines are also set to increase compared with Thursday, while send-out of liquefied natural gas (LNG) was nominated at 36 mcm for Friday, up from the previous day's 33 mcm.

Temperatures across Britain are expected to stay above seasonal averages until at least Sept. 6, meteorologists forecast, suggesting lower demand for gas.

However, analysts at Thomson Reuters Point Carbon said that lower UK continental shelf flows on Monday, as well as escalating tensions between Russia and the west over Ukraine, coul support prices.

Meanwhile, North Sea gas infrastructure operator Gassco said that work at the Troll gas field off Norway, which is cutting output by 46 mcm per day, will end on Sept. 17 - a week later than planned.

That means that a Norwegian Continental Shelf (NCS) outage scheduled to start on Sept. 11, with capacity impact of 59 mcm/day, will overlap the Troll maintenance.

Though Norwegian available production capacity will remain at 45 mcm/day, there is a higher risk that Norwegian flows via Langeled could be disrupted if an unplanned maintenance occurs on those days," Thomson Reuters Point Carbon analysts said. (Reporting by Michael Szabo; Editing by David Goodman)