* Prompt prices up despite mild weather, oversupply
* Currency weakness, carbon gain support curve, prompt
* LNG tanker arrives in UK port
Dec 21 (Reuters) - British wholesale prompt gas prices reversed earlier losses to trade higher on Wednesday, supported by firmer near-curve contracts on the back of a weakening pound against the euro and on rising carbon prices.
The price of gas for immediate delivery rose by 0.10 pence to 45.50 pence per therm by 0946 GMT.
The day-ahead contract also added 0.05 pence to 45.60 pence per therm in response to higher estimated heating demand for Thursday.
"Prompt contracts opened the session lower in line with comfortable supplies and a slight increase in expected temperatures for the coming weeks, though support from gains on the front month has reversed some of these moves," according to Andrew Crabtree, pricing and risk analyst at Wingas UK.
Gas for January delivery traded 0.05 pence higher at 46.25 pence per therm, lifted by sterling currency weakness and rising carbon prices, Crabtree said.
In the European carbon market, the benchmark Dec 17 contract firmed by 0.13 euro to 5.38 euros a tonne.
Trading liquidity was especially poor, which may have also helped influence some of the moves.
"You can tell from the trading liquidity in the market that a lot of people are already off," one trader said in reference to the upcoming Christmas holiday season.
Britain's gas market was oversupplied by 14.3 mcm/day with daily demand estimated at 292.2 mcm/day, according to National Grid data.
Resuming production from Centrica's Barrow North gas terminal, fed by fields in the Irish Sea, is contributing around 7 mcm/day extra gas into the grid.
An unplanned outage saw Barrow idled on Dec. 19.
France's Engie started production at the Cygnus field offshore the UK last week, and supplies continue to ramp-up, analysts said.
Liquefied natural gas (LNG) tanker the Aamira arrived at the UK's port of South Hook but there are no further incoming shipments listed, according to shipping data.
Temperatures across the UK on Wednesday hovered at around 6.8 degrees Celsius, several degrees above earlier expectations.
Thursday however will bring colder weather with forecasters predicting an up to 2.7 degrees Celsius drop versus expectations to around 4.5 degrees Celsius.
Flows from Norway through the Langeled pipeline are currently at around 74 mcm and are forecast to stay close to this level this week, Thomson Reuters analysts said.
In the Netherlands, gas for day-ahead delivery at the TTF hub was up 0.07 euro at 17.80 euros per megawatt-hour. (Reporting by Oleg Vukmanovic, editing by Jeremy Gaunt)