Warm Weather to Dominate U.S., Especially Next Week

December 3,2015

It has not felt much like December so far across parts of the United States, but by next week practically nobody will feel like December in the Lower 48 as above-average temperatures take over virtually the entire country.

Although parts of the Northwest and Midwest saw some wintry weather to start the month, it may be quite some time before the next widespread, significant winter storm threatens the Lower 48.

(MORE: Winter Storm Delphi Recap)

Cold Air Stays Bottled Up North

As we start meteorological winter, which runs from Dec. 1 through Feb. 29, true arctic air remains locked up in extreme northern Canada, well to the north of the U.S. border and even well north of all the major Canadian cities.

While December is early in the winter season, it is quite common for chunks of bitterly cold air to reach the U.S. during the first half of the month.

The forecast for early next week keeps the arctic jet stream north across Canada.

However, most computer model forecast guidance shows no such thing happening right into the middle of this December, as the arctic jet stream remains well to the north in Canada.

Although some cooler air may reach the West later next week, the airmass is projected to be fairly modified, meaning that the coldest air still remains locked up in Canada. The result may only be a drop to near or slightly below average in terms of temperatures.

(Forecast: Denver | San Francisco | Seattle)

Looking Ahead

There are no signs of any blasts of cold air reaching the U.S. in the near future. Outside of some mountains, snow will be hard to come by as well.

Over this weekend, areas of high pressure across the Rockies and East Coast will help keep conditions quiet for most locations. It also means temperatures by Saturday and Sunday could rise to 10 or more degrees above average.

Forecast Highs Compared to Average

Only a portion of the southern Plains and South is expected to see near or below average highs this weekend, as most other parts of the country can expect above average to considerably above average temperatures.

(Forecast: Dallas | Houston | New Orleans)

Into next week, the relative warmth is likely to continue. The most unseasonable warmth is forecast across the northern tier of the country.

Forecast Highs Compared to Average

Temperatures will be even more out of whack in Canada, where the whole country will feel temperatures well above normal into the second week of December. At times parts of central Canada could be up to 40 degrees (24 Celsius degrees) warmer than average, especially in terms of nighttime lows.

Some computer models do show some changes later next week. A storm system may develop over the Plains, perhaps bringing some cooler air back to the West. However, even if such a storm develops, indications are that at least the eastern half of the country stays warmer than average out ahead of it.

Everything seems to be going to plan according to December temperature outlooks that peg much warmer than average conditions across the northern tier. At least for the first two weeks of December, conditions are closely following what is generally expected during a strong El Niño.

(MORE: Strongest El Nino on Record May Jeopardize White Christmas)

Long-range computer models show no significant shift in the pattern for the second half of December either, although there are some signs that parts of the West and Gulf Coast may cool off slightly later in the month.

What Effects Will This Warmth Have?

As a result of the jet stream staying north of the U.S. frequently throughout November, parts of the Northeast and Mid-Atlantic have remained rather mild and snowless recently. Philadelphia saw its second warmest November on record in 2015, and made it through the autumn to the start of December without a freeze for the first time since 1939.

For Buffalo, New York, it was the fourth warmest November on record. Buffalo has also yet to see accumulating snowfall this season through Dec. 3, marking the longest the city has gone in a snow season without receiving measurable snow.

The lack of snowfall and nights below 32 degrees means a tough start for ski resorts in parts of New England and the Appalachians. Over the Great Lakes, on the heels of record late-season ice into spring 2015, lake ice formation may be significantly delayed.

Interestingly enough, a delay in freezing of the lakes could support a later lake-effect snow season, as colder air moving over warmer lake water can lead to the development of heavy snow bands into early winter. This, however, depends on the ability of substantial moisture to coincide with sufficient cold air, something that has struggled to happen so far this season.

(PHOTOS: November 2014 Lake Effect Snow Buries South Buffalo)

It is not just the northeastern quarter of the country that has escaped the bulk of winter’s fury to date. 

Florida, in particular, has been on quite a stretch for above normal temperatures. In November, Naples and Fort Lauderdale recorded their warmest November on record. For Miami and West Palm Beach, it was their second warmest November on record.

Fargo, North Dakota has reached 40 degrees or higher on 256 days so far in 2015. Dating back to 1942, the record is 261 days in 2012, but December 2015 could push them over the edge in just the next two weeks alone.

What About Last Winter?

December 2014 was also a warmer than average month for much of the country. Despite that happening, winter took a fast turnaround in parts of the Northeast.

The pattern changed very quickly in the winter of 2014-15 with record-setting snows hitting parts of New England in January in February.

(MORE: Record New England Snowfall in 2014-15)

There are some differences between this winter and last winter, particularly with the strong El Nino currently in place. 

Regardless, weather patterns are bound to change at some point, so check back regularly with weather.com for the latest information.

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