Winter Outlook Update: January - March 2016 to Feel Influence of Strong El Niño

Jon Erdman
Published: December 18,2015
NOAA and WSI, a division of The Weather Company, issued their January through March 2016 outlooks, and both forecast temperatures and precipitation have the fingerprints of the current strong El Niño, the strongest in 18 years, all over them.
(MORE: El Niño Nears a Peak)
Stronger El Niños typically exhibit their peak influence on North America's weather pattern during the core winter months.
Keep in mind, however, there are several other factors in the atmosphere, operating on shorter time scales, that can, at times, oppose the overall three-month trend.
We'll go into more detail on those patterns following the outlooks a bit later. First, let's take a look at NOAA's outlooks for average temperature and total precipitation across the U.S. for January through March 2016.
These predictions do not project when and where individual storms may occur. An individual cold front or an upper ridge of high pressure can lead to a brief period of colder or warmer weather, respectively, that bucks the overall three-month trend. The same front or area of high pressure can bring a brief period of enhanced precipitation or dry spell that may or may not be indicative of the overall trend that is forecast.

Temperatures

Shaded areas indicate regions where NOAA believes there is a greater-than-average chance that the average temperature from Jan. 1, 2016, through Mar. 31, 2016, will rank among the warmest or coldest one-third of all winters in the 1981-2010 climatological reference period.

For the first three months of 2016, NOAA says the best chance of colder-than-normal temperatures lies in the Deep South, from Texas and New Mexico to Georgia, Florida and South Carolina.

Winter temperature anomalies (above or below average) in the five strongest El Niños prior to 2015-2016.
(NOAA/CPC)

Meanwhile, a large swath of the western and northern United States from California into the Pacific Northwest eastward into the Midwest, Great Lakes and Northeast is expected to be warmer than normal, overall.
"The bulk of the evidence suggests that the November/December pattern will persist into at least the first half of January, with below-normal temperatures being confined to the West and unusually mild weather continuing in the East," wrote Dr. Todd Crawford, WSI chief meteorologist, in their outlook released Friday.
Crawford said there is now "increasing doubt that a sustained cold pattern will ever set up across the Northeast this winter," based on the latest forecast guidance.
In a typical strong El Niño winter, a warm South in December eventually transitions to a colder-than-normal January, February and March, while the northern tier of states remains relatively mild, by winter standards.
(MORE: December's Record-Shattering Warmth)
But that's not always the case. The winters of 1972-73 and 1965-66 were considerably colder in much of the northern tier of states during those strong El Niños, and the winter of 1957-58 was very cold in the Northeast.

Precipitation

Shaded areas indicate regions where NOAA believes there is a greater-than-average chance that the total precipitation from Jan. 1, 2016, through Mar. 31, 2016, will rank among the wettest or driest one-third of all such periods in the 1981-2010 climatological reference period.

NOAA also expects January through March 2016 to trend wetter than usual over much of the southern tier of the nation, from California into the Desert Southwest to the southern and central Plains, as well as the Gulf Coast and Southeast coast, including Florida.
Parts of the Northeast seaboard from the Mid-Atlantic states into southern New England, may also see more precipitation than a typical winter.
Conversely, a relatively dry winter is expected over parts of the Pacific Northwest, northern Rockies and into the far northern Plains, Great Lakes and Ohio Valley.
This precipitation outlook owes to the typical dominance of the subtropical or southern branch jet stream during a strong El Niño winter, bringing more frequent and vigorous low pressure systems along the nation's southern tier.
(MORE: El Niño and Seasonal Snowfall | Your Typically Snowiest Month)

December through March precipitation anomalies in five previous strong El Niños dating to 1950. Green/blue shading corresponds to areas wetter-than-average. Yellow, oranges and reds correspond to drier-than-average areas.

This should at least deliver a significant dent in California's exceptional drought, but even a strong El Niño winter doesn't assure that.
As we discussed in an early December article about the winter outlook, one of the five previous strong El Niño seasons was drier than average in the Golden State (1965-66).
The aforementioned subtropical jet stream usually brings an increase in Pacific storms to California in January and February.
Conversely, drought may either hold steady or expand during the winter in the northern Rockies and northern High Plains, thanks to persistent warmth and expected drier conditions.

El Niño Not the "Be-all and End-all"

A strong El Niño will peak in early winter, influencing the overall temperature and precipitation impacts.
However, three variables, in addition to El Niño, could play an important role in early 2016, including the North Atlantic Oscillation, the Arctic Oscillation and the Madden-Julian Oscillation. These features can be difficult to forecast more than a few weeks in advance.
The North Atlantic Oscillation (NAO) basically describes the degree of blocking of the jet stream over the North Atlantic Ocean, frequently in the vicinity of Greenland. The NAO's negative phase features high pressure aloft blocking the west-to-east flow of the jet stream, forcing it to buckle south over the eastern U.S., ushering in prolonged cold air. The positive phase is just the opposite; no blocking means Canadian cold air mainly drains west-to-east across the content, not plunging deep into the U.S.
The Arctic Oscillation is a climate pattern characterized by the strength of counterclockwise winds around the Arctic. Its positive phase confines cold air to the polar regions, while its negative phase is associated with cold air penetrating farther south, as well as an increased chance of nor'easters.
(MORE: Winter Storm Names 2015-2016 | The Science Behind Naming Winter Storms)
The Madden-Julian Oscillation is associated with variations in tropical thunderstorm activity (convection) and is characterized by an eastward-moving pulse of atmospheric features affecting cloud formation, precipitation and pressure patterns. This pulse circles the globe roughly once every one to two months. In turn, the jet streams over the North Pacific and South Pacific can be impacted during the winter due to large-scale changes in tropical convection. This can contribute to blocking activity which impacts the amount of precipitation across the Pacific Northwest.

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