The 2015–16 North American winter was not as frigid across North America and the United States (especially the East Coast) as compared to the 2013–14 and 2014–15 winters. This was mainly due to a strong El Niño, which caused generally warmer-than-average conditions. However, despite the warmth, significant weather systems still occurred, including a snowstorm and flash flooding in Texas at the end of December and a large tornado outbreak at the end of February. The main event of the winter season, by far and large, was when a crippling and historic blizzard struck the Northeastern United States in late January, dumping up to of snow in and around the metropolitan areas. Several other smaller snow events affected the Northeast as well, but for the most part the heaviest snowstorms and ice stayed out further west, such as a severe blizzard in western Texas in late December (producing a tornado outbreak as well), and a major late-season snowstorm in Colorado in mid-April.
While there is no well-agreed-upon date used to indicate the start of winter in the Northern Hemisphere, there are two definitions of winter which may be used. Based on the astronomical definition, winter begins at the winter solstice, which in 2015 occurred late on December 21, and ends at the March equinox, which in 2016 occurred on March 20. Based on the meteorological definition, the first day of winter is December 1 and the last day February 29. Both definitions involve a period of approximately three months, with some variability. Winter is often defined by meteorologists to be the three calendar months with the lowest average temperatures. Since both definitions span the calendar year, it is possible to have a winter storm in two different years.
Seasonal forecasts
On October 15, 2015, the National Oceanic and Atmospheric Administration's Climate Prediction Center issued its U.S. Winter Outlook. The presence of a strong El Niño event was expected to affect weather and climate patterns by influencing the position of the Pacific jet stream. According to CPC deputy director Mike Halpert at the time of the outlook, "A strong El Niño is in place and should exert a strong influence over our weather this winter" and "While temperature and precipitation impacts associated with El Niño are favored, El Niño is not the only player. Cold-air outbreaks and snow storms will likely occur at times this winter. However, the frequency, number and intensity of these events cannot be predicted on a seasonal timescale." Other oscillations anticipated to have some effect on winter in the United States were the Arctic oscillation and the Madden–Julian oscillation. The precipitation outlook indicated an elevated likelihood of above-average levels precipitation from central and southern California to Texas and Florida and northward to southern parts of New England. Above-average precipitation was also favored in southeastern Alaska, with below-average levels of precipitation favored in central and western Alaska, parts of the Northwestern U.S. and northern Rocky Mountain states, and areas in the vicinity of the Great Lakes and Ohio Valley.
The temperature outlook favored below-average temperatures in the southern Plains and Southeastern United States. Above-average temperatures were most favored across the West and the northern half of the contiguous United States and Alaska and Hawaii. The drought outlook anticipated improvement in conditions in central and southern California by the end of January 2016, noting the possibility of additional alleviation of drought conditions in February and March. The outlook favored the removal of drought across large parts of the Southwestern U.S., with additional lessening or elimination of drought conditions likely in the southern Plains. Drought conditions were expected to persist across the Pacific Northwest and northern Rocky Mountains, with development likely in Hawaii and areas in the vicinity of the northern Great Lakes region.
On November 30, 2015, Environment Canada issued its winter outlook for December, January, and February, as part of their monthly climate outlooks. Above-average temperatures were favoured throughout most of Canada, with the exception of northern Quebec and the southern tip of Baffin Island; areas that were considered the most likely to see above normal temperatures included the Lower Mainland of British Columbia, the Maritime provinces, southern Newfoundland, central Quebec and Ontario, and northern Manitoba and Saskatchewan; in those areas, the probability of above-normal temperatures was over 80%. The areas where below-normal temperatures were favoured included extreme northern areas of Quebec and Labrador, along with southern parts of Baffin Island. Above average precipitation was favoured in the Lower Mainland of B.C., New Brunswick, northern Quebec, northern Newfoundland, the Northwest Territories, and western Nunavut. Below-average precipitation was favoured on the south-eastern tip of Baffin Island and a small area just north of Lake Superior.
Seasonal summary
The winter of 2015–16 was quite unusual in terms of winter weather. First, around the end of November near Black Friday, a crippling ice storm hit the Southern and Central Plains with as much as of ice accumulation in some areas, knocking out power to over 100,000 residents. In December, two winter storms impacted the Great Lakes, with the latter one being a bit farther to the west, both brought roughly a foot of snow in some locations. Normally, in this area, this is not common, but the super El Niño may have been a contributor to this. Following that, the nation had one of the warmest Decembers on record, with New York City being as warm as on Christmas Eve (December 24). This was the warmest temperature in New York City in the second half of December on record. The low that day of was the warmest December low on record in New York. Record-Breaking Christmas Heat Clinches Record Warm December For Hundreds of Cities, Weather Channel, January 2, 2016 In fact, across the Lower 48, this was the warmest and wettest December on record at the time. Every single state in the Northeastern United States saw a record warm December.December 2015 National Climate Report, NOAA In 2021, an even warmer December was recorded across the Lower 48, with a mean temperature of rather than .December 2021 National Climate Report, NOAA This meant Buffalo, New York until December 18, a record for latest first snow.Buffalo, New York, Finally Saw Its First Measurable Snow of the Season Friday, The Weather Channel, December 20, 2015 A strong tornado outbreak also occurred from December 23–25, which a very similar event had occurred the year before, just weaker. After this system passed, a larger storm complex moved through the same areas impacted by the ice storm from Black Friday 2015. This storm brought blizzard conditions to parts of Texas and New Mexico, with areas reaching up to close to 2 feet of snow in parts of Texas, which is a rare event in that state. For comparison, the last time this has occurred (or near the same areas), was in 2011 during the Groundhog Day blizzard.
The month of January 2016 was variable in its weather patterns. Following the warm trend in December, an early cold snap brought close-to-average temperatures to the East Coast, at the same time a storm complex was moving through the Northeast, and due to the fresh batch of cold air, it was able to produce some snow on the back side of it. At the opposite end of the spectrum, the West Coast was receiving needed rainfall to help during its long-time drought. This brief period of relief soon ended. After that, around January 16–17, a potent storm system moved up the East Coast, bringing the first snowfall of the season to areas like Philadelphia and New York City. A few days later, an Alberta clipper moved through the central United States, producing a swath of snow from Illinois to North Carolina. This small system was then proceeded and eclipsed by a crippling and historic blizzard just days later on January 22–23. Cities like Washington D.C., Philadelphia, and New York City were buried with of snow, breaking numerous records. At the start of February, another snowstorm kicked off the month with a swath of snow from Colorado to Michigan. Snow accumulations ranged from , along with winds up to . After the storm system passed, its cold front transformed into another snowstorm for the East Coast, with snowfall amounts up to 8 inches. Multiple winter storms proceeded to affect the Northeast during a two-week period in early-to-mid February, and the coldest air of the season arrived by February 14, parts of the Northeast on February 14, with temperatures dipping to as low as , shattering many record low temperatures.
Historic flash flooding occurred in the southern U.S due to a very slow-moving system in early March. At the same time, record-breaking temperatures pushed into the Northeast, with some areas reaching into the low 80s. Later that month, another blizzard occurred in the High Plains, and dropped up to of snow in parts of the High Plains and the Great Lakes through March 23–25, along with bringing a significant ice storm to parts of New England, with accumulations of of ice in some areas. The final winter weather event occurred in mid-April, upper-level low stalled in the West, producing a major snowstorm that affected the High Plains and Rocky Mountains in areas near the Denver metropolitan area, dumping up to of heavy snow, which led to power outages. The storm also produced record rainfall of up to , leading to severe flash floods.
Events Late November ice storm Around Black Friday of 2015, a major ice storm occurred in the Southern Central Plains, with areas receiving up to of the frozen precipitation. Residents in the areas were without powers for days, if not weeks. The storm also brought snow to parts of the Midwest, with accumulations up to of snow. Historic rainfall also fell too, breaking numerous records. On November 25, an area of low pressure system moved through the West and central Midwest, dropping snow of up to , and also brought the first cold blast of the winter season. At the same time, incoming moisture from weakening Hurricane Sandra in the East Pacific was starting to streak through Mexico into the southwestern United States. Interacting with the low pressure area, this combined to produce a plume of precipitation from ice to rain from southern Texas into Minnesota, due to high pressure situated off Maine keeping the Northeast dry for the holiday.
While causing a potent ice storm on its cold side, on the warm sector of the system, severe floods occurred as well, with areas like McKinney in Texas receiving up to of rain over a 4-day period, causing major flooding. Some areas even broke their records for yearly rainfall totals from this system, due to the axis of moisture shooting into Canada. In total, 17 people died, including six in Kansas, three in Texas, three in Missouri and one in Utah, and over 110,000 left without power, especially around Oklahoma City.Winter Storm Cara State-by-State: 17 Killed in Southern Plains; Thousands Still Without Power in Oklahoma, The Weather Channel, March 23, 2016
Post-Christmas storm complex