The northern United States and southern Canada will be dominated by colder-than-normal temperatures over the next three months, while above-normal temperatures are expected across the U.S. South, according to forecasters at Weather Services International (WSI). The heavily populated Boston-to-Washington, DC, corridor may avoid much of the winter’s coldest weather, WSI said.

“The brutally cold early winter weather across the eastern United States has been the result of a seemingly endless supply of Arctic air masses plowing southeastward across Canada,” said WSI Chief Meteorologist Todd Crawford. “This pattern has been driven by strong and persistent atmospheric ridging across the North Pacific. As long as this ridging continues, the risk of widespread cold temperatures will continue. However, any weakening or displacement of this ridging will lead to significantly warmer risks across the United States due to the expected strength of the polar vortex.

“There are several reasons why we expect a stronger-than-normal polar vortex this winter, including a weaker-than-normal Siberian high, a recent spike in solar activity, and the continuation of very strong westerly winds in the equatorial stratosphere. This strong polar vortex should generally confine the cold air to northern latitudes, and should allow much of the South to bask in a mild winter.”

WSI expects temperatures in December to average colder-than-normal across the northern tier, except the southern portion of the Northeast, including the Boston-to-Washington corridor, which, along with the southern United States, is likely to be warmer than normal, WSI said.

“Considering the slightly warmer-than-normal December forecast for the South and along the East Coast (including major demand centers like Boston, New York City and Washington, DC), we believe aggregate natural gas demand will run slightly below normal between Thanksgiving and the end of the year,” said Energy Securities Analysis Inc. (ESAI) Senior Analyst Chris Kostas. “New York City could experience relatively soft delivered gas prices in December given the slightly warmer-than-normal weather forecast and Spectra Energy’s recently completed New Jersey-New York pipeline upgrade (which is capable of delivering an additional 0.8 Bcf/day of natural gas into New York City [see Daily GPI,Oct. 22]. Natural gas prices at Henry Hub should also find bearish pricing pressures in December given the expectation for mild southern temperatures.”

Warmer-than-normal temperatures will move into all but the northernmost sections of the Northwest and North-Central regions in January and will remain in place over the Boston-to-Washington corridor and the South, according to WSI.

“If warmer-than-normal temperatures materialize over much of the country as WSI expects, North American natural-gas prices could soften considerably in January,” Kostas said. “Warmer-than-normal January temperatures would also provide an inventory overhang for the second half of the winter.

“Robust inventories at the end of January would increase downside price risk for the February-March period. Delivered natural-gas prices in PJM and New York could hit very soft levels in January considering the significant year-over-year increase in shale gas production in Pennsylvania. Winter price expectations in New England (i.e., Algonquin Citygate) have been extraordinarily high this year, with January price quotes approaching $15.00/MMBtu. We believe New England gas prices will average below that level in January given the warmer-than-normal temperatures expected over the southern portion of the region.”

WSI expects colder temperatures to finally take over throughout all of the Northeast — including the Boston-to-Washington corridor — and the North-Central in February.

“Slightly colder-than-normal Northeast and Midwest temperatures in February should help to firm up natural-gas demand and delivered prices in PJM, New York and New England,” Kostas said. “Mild temperatures elsewhere, however, should help to offset the increase in Northeast natural-gas demand. While February prices will depend on the level of cold in the Northeast and the number of cumulative population-weighted heating degree days across the country, we believe downside fundamental risk has developed given the forecast for a mild January-February period.”

WSI’s forecast dovetails with the National Oceanic and Atmospheric Administration’s (NOAA) recently released Winter Outlook, which called for above-average temperatures across most of the South and portions of New England (see Daily GPI,Nov. 21). Forecasters at the Farmers’ Almanac, on the other hand, expect the winter will be colder than normal for most of the United States (see Daily GPI,Aug. 27).

With the exception of localized spikes during periods of high demand, natural gas prices aren’t expected to increase significantly this winter, according to the Federal Energy Regulatory Commission’s Winter 2013-2014 Energy Market Assessment (see Daily GPI,Oct. 17). And the U.S. Energy Information Administration — which expects the Henry Hub spot price for natural gas to increase to $4.00/MMBtu next year, compared with an estimated $3.71/MMBtu this year — expects average winter temperatures this year to be roughly in line with the 10-year average (see Daily GPI,Oct. 9).

Barring unexpectedly cold weather this winter, rising natural gas production will prevent prices from eclipsing $4/MMBtu, according to BNP Paribas’ Teri Viswanath, director of commodity strategy (see Daily GPI,Nov. 11). BNP Paribas’ latest price forecast sees natural gas at $3.55/MMBtu in 4Q2013, $3.90/MMBtu in 1Q2014, and $4.20/MMBtu by 4Q2014.