Warmer-than-normal temperatures are expected to be in place in the Northeast and across the south-central and western areas as well in September, while the Southeast and north-central areas will average cooler than normal, according to forecasters at Weather Services International (WSI).

That scenario could keep natural gas prices soft in New England past Halloween, according to Energy Securities Analysis Inc. Senior Analyst Chris Kostas. And the temperature forecast map isn’t likely to change any time soon.

While the East and most of the central United States have experienced fewer cooling degree days this month than in a typical August, New England, the Mid-Atlantic and some other regions — and the country as a whole — have accumulated more cooling degree days during the entire season than normal, according to National Weather Service data. A degree day is the difference between the mean daily temperature and the 65-degree Fahrenheit base.

“The summer has followed the general pattern established earlier in 2013 of below-normal temperatures extending from the northern Plains into the Southeast, with above-normal temperatures elsewhere. Strangely enough, our latest dynamical and statistical model guidance suggests that this pattern will persist through the fall season,” said WSI Chief Meteorologist Todd Crawford.

“Of course, the large-scale pattern is often modulated by the impact of re-curving tropical cyclones in September and October, and individual paths of these cyclones are unpredictable at long lead times. Because of this, confidence in the fall forecast, as is often the case, is reduced from typical values. Some of our indicators are beginning to suggest that a pattern change toward warmer-than-normal temperatures may occur across the northern Plains in November, so there is a warmer risk to our forecast in that region.”

Cooler-than-normal temperatures in the Midwest and Mid-Atlantic regions in September should help keep electrical loads below seasonal norms and push power prices and implied market heat-rates lower, according to Kostas. “Delivered natural gas in those regions should also see downward pricing pressure,” he said.

“Considering persistent negative basis prices seen between the Mid-Atlantic region and Henry Hub this past summer, discounts to Henry Hub are likely to increase in duration and magnitude as electrical load and gas demand softens in September. California and Texas, on the other hand, may see firm power prices and implied market heat-rates in September due to above-normal temperatures expected in those regions. Generator outages will also help to support prices as baseload generators begin their maintenance season. In California, reduced Northwest imports should also help to support power prices as run-of-river hydroelectric generation declines.”

With the warmer-than-normal trend hanging on in New England in October, “delivered natural gas prices may remain soft (especially if Canadian imports increase as expected due to new offshore production at Deep Panuke),” Kostas said.

“…With aggregate North American heating and cooling demand expected to be soft in October, natural-gas inventories are likely to close the year-over-year deficit by the end of the month. Weak natural gas demand from the power sector in August, coupled with the expected soft demand in September and October should allow inventories to challenge last year’s record. This would be bearish for natural gas prices in October in particular, and the winter in general, but is dependent on the mild weather forecast for the September/October time frame.”

WSI’s temperature forecast map remains unchanged in November, with a third straight month of cooler-than-normal temperatures expected in the Southeast.

“This should help to lift mid-Atlantic delivered gas prices from the very soft levels we expect in October,” Kostas said. “The South is expected to be split between cooler-than-normal temperatures in Florida and warmer-than-normal temperatures in Texas.”

In a preview of WSI’s winter forecast, Crawford said there is some indication that there may be some colder-than-normal months ahead.

“A very early look at indicators for the upcoming winter suggest that atmospheric blocking may be favored again this winter, which would favor below-normal temperatures across significant parts of the United States,” Crawford said. “However, it is still too early to have any reasonable level of confidence in the winter forecast since many of the key drivers don’t reveal themselves until October, which is when our first official winter forecast will be released.”