The North American winter season to date has expressed a significant level of variance.
First, a cyclone in the Bering Sea enabled a change in the atmospheric pattern to occur; according to Jeff Masters from Weather Underground, this cyclone brought about a "ripple" in the jet stream, and the presence of a high-pressure ridge over the western United States and a low-pressure trough over the southern and central United States enabled a great intrusion of very cold air to pervade southward out of Canada.
Following the onset of the cold wave, multiple snow events occurred; one significant storm dropped as much as 88 inches (220 cm) of snow in a single area, and impacts covered a broad area.
In December, yet another storm impacted parts of North America; the storm brought relief to drought-stricken parts of California, but it also brought dangerous mudflows to fire-ravaged areas where the soil could not handle the excess precipitation.
Less than two weeks after this events, another storm impacted the Pacific coast of the United States; this storm, fueled by the "Pineapple Express", knocked out power to over one hundred thousand customers in the San Francisco Bay Area after producing strong winds.
Hurricane-force winds were reported in parts of the northwestern United States.
Regions reported as much as 9 inches (23 cm) of rainfall, and parts of the Sierra Nevada reported 19 inches (48 cm) of snowfall.

Due to a persistent stationary high-pressure pattern over the west coast that redirects the jet stream, it remained (and remains) in a wavy ideal configuration to bring warm air north over the western U.S. and cold air towards the south over the continental states, and to favor winter storms over the East Coast.
Severe winter blizzards over New England are often associated with this configuration, and nearly all of the snow storms this season followed very similar tracks and had marked similarities in their synoptic evolution.
Boston in particular saw the effects of this, experiencing six major snow storms in the first two months of the year, leaving it with over 105 inches (270 cm) of snow.
January 27 saw first major snowfall of 2015, with observations showing a blocked flow with warm air over the west coast, accompanied by a pronounced cold trough downstream, which pattern looks very similar to the blizzard that Boston saw on January 23, 2005.

As a result, February was record-breaking for many cities in the United States, yet in opposite extremes.
Much of February saw below-average cold in the eastern part of the country, it was markedly warm in the West.
A multitude of cities east of the Mississippi experienced their coldest February in decades, including Chicago, Ill.; Cleveland, Oh.;
Grand Rapids, Mich.; Harrisburg, Pa.; Hartford, Conn.; and Portland, Maine.
Marquette, Mich. Syracuse, Buffalo and Rochester, N.Y. also set records for coldest month overall, as did Bangor, Maine where the average temperature was 6.1 °F (−14.4 °C).
And with an average temperature of 2.5 °F (−16.4 °C), the state of Maine itself also set a record low.
For Worcester, Mass, February was the coldest month out of any month on record with an average temperature of just 14.2 °F (−9.9 °C), while also accumulating more than 110 inches (280 cm) of snow this winter.

In contrast, in the West a persistently strong ridge of high pressure over the warm eastern Pacific Ocean and western North America elevated temperatures to record levels from Arizona to Washington.
It was the warmest winter month (December, January, February) on record in San Francisco; Seattle; Portland, Ore.; Reno, Nev.; Las Vegas; and Salt Lake City, with the latter realizing an average temperature for February of 43.9 °F (6.6 °C), breaking the old record set in 1907.
Meanwhile, just 1.1 inches (2.8 cm) of snow fell in the entire month in Anchorage, Alaska, making it the fifth-least-snowy February on record.

Portland and Salem had their warmest February on record, with the latter tying the record set in 1934 for their warmest at 45.9 °F (7.7 °C) degrees with the year.
For the first time in
The North American winter season to date has expressed a significant level of variance. First, a cyclone in the Bering Sea enabled a change in the atmospheric pattern to occur; according to Jeff Masters from Weather Underground, this cyclone brought about a "ripple" in the jet stream, and the presence of a high-pressure ridge over the western United States and a low-pressure trough over the southern and central United States enabled a great intrusion of very cold air to pervade southward out of Canada. Following the onset of the cold wave, multiple snow events occurred; one significant storm dropped as much as 88 inches (220 cm) of snow in a single area, and impacts covered a broad area. In December, yet another storm impacted parts of North America; the storm brought relief to drought-stricken parts of California, but it also brought dangerous mudflows to fire-ravaged areas where the soil could not handle the excess precipitation. Less than two weeks after this events, another storm impacted the Pacific coast of the United States; this storm, fueled by the "Pineapple Express", knocked out power to over one hundred thousand customers in the San Francisco Bay Area after producing strong winds. Hurricane-force winds were reported in parts of the northwestern United States. Regions reported as much as 9 inches (23 cm) of rainfall, and parts of the Sierra Nevada reported 19 inches (48 cm) of snowfall.
Due to a persistent stationary high-pressure pattern over the west coast that redirects the jet stream, it remained (and remains) in a wavy ideal configuration to bring warm air north over the western U.S. and cold air towards the south over the continental states, and to favor winter storms over the East Coast. Severe winter blizzards over New England are often associated with this configuration, and nearly all of the snow storms this season followed very similar tracks and had marked similarities in their synoptic evolution. Boston in particular saw the effects of this, experiencing six major snow storms in the first two months of the year, leaving it with over 105 inches (270 cm) of snow. January 27 saw first major snowfall of 2015, with observations showing a blocked flow with warm air over the west coast, accompanied by a pronounced cold trough downstream, which pattern looks very similar to the blizzard that Boston saw on January 23, 2005.
As a result, February was record-breaking for many cities in the United States, yet in opposite extremes. Much of February saw below-average cold in the eastern part of the country, it was markedly warm in the West. A multitude of cities east of the Mississippi experienced their coldest February in decades, including Chicago, Ill.; Cleveland, Oh.; Grand Rapids, Mich.; Harrisburg, Pa.; Hartford, Conn.; and Portland, Maine. Marquette, Mich. Syracuse, Buffalo and Rochester, N.Y. also set records for coldest month overall, as did Bangor, Maine where the average temperature was 6.1 °F (−14.4 °C). And with an average temperature of 2.5 °F (−16.4 °C), the state of Maine itself also set a record low. For Worcester, Mass, February was the coldest month out of any month on record with an average temperature of just 14.2 °F (−9.9 °C), while also accumulating more than 110 inches (280 cm) of snow this winter.
In contrast, in the West a persistently strong ridge of high pressure over the warm eastern Pacific Ocean and western North America elevated temperatures to record levels from Arizona to Washington. It was the warmest winter month (December, January, February) on record in San Francisco; Seattle; Portland, Ore.; Reno, Nev.; Las Vegas; and Salt Lake City, with the latter realizing an average temperature for February of 43.9 °F (6.6 °C), breaking the old record set in 1907. Meanwhile, just 1.1 inches (2.8 cm) of snow fell in the entire month in Anchorage, Alaska, making it the fifth-least-snowy February on record.
Portland and Salem had their warmest February on record, with the latter tying the record set in 1934 for their warmest at 45.9 °F (7.7 °C) degrees with the year. For the first time in
2014–15 North American winter