Winter volatility saw Western natural gas forward hubs post huge gains during the Dec. 15-21 trading period, while expectations for a very mild start to 2023 drove deep discounts elsewhere in the Lower 48, NGI’s Forward Look data show.

With intense Arctic cold diving from the Northwest into the heart of the Lower 48, spot market prices surged Wednesday, with gains particularly pronounced in the Rockies and California regions, Daily GPI data show. Day-ahead prices skyrocketed $25-plus day/day at most western U.S. hubs.

Western markets have been no stranger to price spikes this season; the West Coast bore the brunt of wintry weather during an otherwise mild start to December for the Lower 48, one of a number of factors that have contributed to elevated physical market prices out...