- Gas for power demand was expected 8 mcm/day higher on Monday amid lower wind, however, according to Refinitiv data.
British gas prices across the curve declined on Friday morning amid plentiful supply and milder weather forecasts.
The day-ahead contract was down 0.25 pence to 35.25 pence per therm at 0908 GMT.
The system was over-supplied by 25 million cubic metres (mcm), with demand forecast at 245 mcm and flows at 270 mcm/day, National Grid data showed.
"The strongly oversupplied system on the opening today should provide an important bearish signal to the physical prices," said analysts at Refinitiv in a daily report.
The oversupply stemmed from higher flows of Norwegian gas and a 19 mcm rise in sendout of liquefied natural gas (LNG) due to a busy tanker arrival schedule, they said.
Gas for power demand was expected 8 mcm/day higher on Monday amid lower wind, however, according to Refinitiv data.
Peak wind generation is forecast at 14 gigawatts (GW) on Friday and 11.7 GW on Monday, out of total metered capacity of around 18 GW, Elexon data showed.
Along the curve, December gas on the NBP fell 0.60 pence to 36.20 pence per therm.
Temperatures in December were now forecast milder than previously, Refinitiv's analysts said.
Analysts at Energy Aspects said in a note they had lowered their UK winter demand outlook for December 2020-March 2021, to a rise of 0.16 billion cubic metres (bcm) bcm year on year from a 0.4 bcm y/y rise previously, due to mild weather and the re-imposition of nationwide COVID-19 lockdown measures.
Still, Norwegian gas flows to Norway should rise by 1.2 bcm y/y over the winter period, they added.
The December price at the Dutch TTF hub was 0.15 euro lower at 12.80 euros per megawatt hour.
The benchmark Dec-20 EU carbon contract was up 0.18 euro at 26.53 euros a tonne.