British and Dutch prompt wholesale gas prices mostly rose on Monday morning, amid forecasts of colder weather and lower LNG send-out in Britain due to high wind speeds.

The British within-day contract TRGBNBPWKD rose by 12.00 pence to 160.00 pence per therm by 0909 GMT, while the day-ahead contract TRGBNBPD1 rose by 1.50 pence to 160.00 pence/therm, according to Refinitiv Eikon data.

The British gas system was 9.1 MMcm under-supplied, National Grid data showed.

"The stormy winds continue blowing at Milford Haven and LNG send-out has stepped further lower over the weekend," Refinitiv analyst Marina Tsygankova said in morning note.

Wind speeds are expected to stay strong for most of the week, posing a risk of reduced LNG deliveries into the UK gas system despite a many cargoes queueing, she added.

There are currently 10 tankers scheduled to unload at the Milford Haven terminals Dragon and South Hook over the next three days. 

"The generally unsettled trend with slowly decreasing temperatures remains stable so that the mild and unsettled next few days will be followed by slightly cooler weather next week," Refinitiv meteorologist Georg Mueller said.

Refinitiv is forecasting British local distribution zone gas demand, which is primarily used for heating, at 174 MMcm for Jan. 10, rising to 219 MMcm for the working days next week but levels are still below the seasonal norm.

Peak wind generation is set to rise from 16.2 gigawatts (GW) on Monday to 18.3 GW on Tuesday, out of a total metered capacity of more than 22 GW, Elexon data showed.

The Dutch front-month contract TRNLTTFMc1, a European benchmark, was up 2.30 euros at 70.00 euros per megawatt hour (MWh), while the March contract TRNLTTFMc2 was down 1.50 euros at 70.00 euros/MWh.

"For me, it's a sideway move. The picture doesn't look too bullish, with the mild weather, low demand and high gas storages," a trader said.

Europe-wide gas storages were 83.1% full, with the region's biggest consumer Germany continuing to add gas to storages, which are 91.1% full, according to Gas Infrastructure Europe data.

Germany has enough gas to get through the current winter, the head of the country's network regulator said at the weekend.

In the European carbon market, the benchmark contract CFI2Zc1 rose by 0.56 euros to 77.95 euros a tonne.