Both natural gas cash and futures markets rocketed higher Monday as more deferred weather forecasts turned sharply colder. Only a single point followed by NGI was unchanged, and all other locations were deep into double-digit gains.

The NGI National Spot Gas Average rose 34 cents to $3.63, with the Northeast leading the charge higher. Futures opened up over a dime and kept on advancing. At the close, January had risen 21.8 cents to $3.654 to post another two-year high, and February was up 20.1 cents to $3.641. January crude oil rose 11 cents to $51.79/bbl.

Weather models turned significantly colder in the more deferred periods.

Monday’s 11-15-day forecast was “colder than Friday’s forecast for days 11-12, especially over the north-central U.S. and Canada,” said WSI Corp. in its Monday morning report to clients. “The Southwest and southern tier are a bit warmer.” Continental U.S. gas-weighted heating degree days (HDD) were up “3.4 for those two days and are now forecast to be 156 for the whole period.”

WSI said even with the changes to the forecast, “there is a greater colder risk versus warmer risk for the northern and eastern U.S. The West, mainly California and the Southwest have warmer risks.”

Traders see the market poised for further advances. Not only did Monday’s advance reach the highest point since December 2014, but trading volume was at new highs.

“We haven’t seen this move in quite a while and volume was also good,” said a New York floor trader. “January volume was 257,000,” he said shortly after the close of floor trading. “It’s a good move for the market and reinforces that $3.50 ought to be solid support, and near term resistance is now $3.75.”

Tim Evans of Citi Futures Perspective saw the market “trading sharply higher than on Friday as a significant cold air mass pooling over Western Canada is seen resulting in ongoing lower-than-normal readings across the balance of Canada and the northern U.S. over the next two weeks.”

According to Evans’ figures, current inventories of 3,995 Bcf still stand 235 Bcf higher than the five-year average, “but the cold will be eroding that year-on-five-year average surplus in coming weeks…”

Near-term heating loads are forecast to be about average. For the week ending Dec. 10, the National Weather Service (NWS) predicted that New England would see 240 HDD, or three fewer than normal. The Mid-Atlantic is expected to experience 200 HDD, or seven under its normal tally, and the greater Midwest from Ohio to Wisconsin is anticipated to endure 241 HDD, or five more than its seasonal norm.

Barclays Commodities Research sees a sharp decline in storage.

“The natural gas market got a big boost [last] week as December weather forecasts turned colder,” said Barclays analyst Nicholas Potter in a note to clients. “This should be the first burst of cold, marking the true start to the winter of 2016-2017 heating season. As the cold hits, storage withdrawals should pick up further, aided by higher year/year export levels and lower production.

“The market should read this fast pace of withdrawals as bullish. By the end of December, we forecast storage inventories will be below 2015 levels for the first time this year and within striking range of the five-year average.”

Eastern points showed the day’s greatest gains in physical market trading, although near-term temperature forecasts hovered right at seasonal norms. Forecaster said Monday’s high in New York of 49 would slide to 46 Tuesday before reaching 47 Wednesday, right at normal. Boston’s high of 39 Monday was seen climbing to 43 Tuesday and 45 Wednesday, also normal for this time of year.

Gas at the Algonquin Citygate jumped $1.69 to $6.01, and deliveries to Iroquois, Waddington added 44 cents to $4.35. Gas on Tennessee Zone 6 200 L soared $1.97 to $6.18.

Major market centers also posted strong advances. Gas at the Chicago Citygate rose 21 cents to $3.62, and gas at the Henry Hub added 19 cents to $3.60. Gas at the NGPL Midcontinent Pool changed hands 24 cents higher at $3.46, and Kern Receipts came in at $3.54, up 36 cents. Gas at the SoCal Citygate rose 45 cents to $3.86.

If forecast cold weren’t enough to propel prices higher, Rockies Express Pipeline (REX) reported that production would be temporarily reduced as it “conducts another smart pig run at the eastern end of the pipe, which may impact up to 500 MMcf/d of flow,” said industry consultant Genscape Inc.

Tuesday’s pig run was to take place near Chandlersville, OH. “Previous runs at this segment have impacted between 50 and 500 MMcf/d,” Genscape said. Last week, REX did a pig run near Clarington (non-Tenn), OH, “which resulted in flows through Segment 390 dropping about 519 MMcf/d day-over-day on gas day Nov.1.”

Marcellus points rose. Gas on Dominion South jumped 35 cents to $3.05, and deliveries on Tennessee Zn 4 Marcellus added 31 cents to $2.99. Gas on Transco-Leidy Line was quoted at $3.04, up 35 cents.

Drilling rigs keep returning to the onshore. Texas and the Permian Basin again led among states and plays, respectively, in the return of U.S. land-based drilling rigs, according to the Baker Hughes Inc.’s weekly rig count.