Winter Summary 2016-17
 

It was a manageable winter season for 2016-17, with snow averaging within 10 to 20 percent of normal and arctic outbreaks of cold air few and brief.

Air temperatures averaged above normal through the months of November through February, and it was not until March that the first below normal temperature month occurred. Two years after the historic cold February of 2015, February 2017 finished as the warmest February on record. We did have arctic outbreaks, and though the cold spells were brief, they did contribute to an average amount of lake effect snow events. Of these 10 lake effect events, 6 produced over three feet of snow east of either Lake Erie or Lake Ontario.  

The warm temperatures this winter and limited cold spells allowed for little ice to form on area creeks and rivers. As a result flooding of creeks and rivers this season was due to excessive rain and snow melt. On January 12-13^th heavy rain and snow melt across the Southern Tier brought several creeks and streams out of their banks. Additional flooding of small creeks and streams due to heavy rain and snow melt occurred on the 25^th and 26^th of February across the Eastern Lake Ontario region, and on the 7^th through the 10^th of April across the Genesee Valley and Finger Lakes region. Lake Erie never completely froze over this winter season, though there was considerable lake shore ice.

Snowfall

An atypical start to this winter season as the first significant snow event fell south and southeast of Lake Ontario, and not from off Lake Erie. There was a hybrid synoptic/lake effect snow event in late November that with a northwest wind brought over a foot of snow from near Rochester to the southern Tug Hill region. The 11.2 inches of snow that fell on November 20^th in Rochester N.Y. tied for the third greatest November calendar day snow event.

Following a cold front on December 8^th, lake effect snow became more frequent and common across the Eastern Great Lakes region. A long lasting event on the 8^th through 11^th of December brought the first significant snows off Lake Erie, with over three feet of snow falling along the Chautauqua Ridge. This lake effect event was followed by two more in December, and two in January. The most active month for lake effect snow events was February, with four such events; despite February being the warmest February of all-time. There were two synoptic events that produced over 7 inches of snow across the region. The first was on February 11^th and 12^th that brought just over a foot of snow to the Eastern Lake Ontario region. Farther westward, across Western New York snow from this nearby nor’easter was less than a half a foot. A second nor’easter on March 13^th through 14^th brought heavy snow across the entire region, with totals of a foot and a half to more than two feet across much of the northern half of Western New York.

A cut off low pressure brought the season’s final snow of several inches on April 6^th and 7^th. This brought many areas to within 10 to 20 percent of their normal season snowfall.

Temperatures

Four of the five winter months finished with above normal temperatures this winter season, with just the month of March finishing below normal. November through January finished several degrees above normal. February began in similar fashion, with above normal temperature days outnumbering below normal days. Then over the last 10 days of the month very mild air built across the region, with the warmth reaching a pinnacle on the 24^th and 25^th of the month as the warmest February day ever. This 10-day stretch brought the month of February into the record books as well as the warmest February on record.

Winter was not done, and what the season had in store for March was unlike February. Cold, but not harshly cold days persisted through much of the month, such that March finished not only below normal, but also colder than February. This was the first this has happened for much of Western and North Central New York since 1984.  

Winter Statistics for Buffalo and Rochester

Buffalo

Average Temperature November – March: 35.0F (3.8F above normal)

Snowfall: 76.1”  18.1” below normal (ranked 55^th least of 133 years)

Days with 1” of snow or more on ground: 49 (ranked 15^th (tie) least of 124 years)

Rochester

Average Temperature November – March: 33.2F (2.0 above normal)

Snowfall: 107.1”   8.4” above normal (ranked 28^th snowiest of 133 years)

Days with 1” of snow or more on ground: 59 (ranked 17^th (tie) least of 124 years)

Buffalo

Rochester

Watertown

Hemispheric Pattern

Contrary to many long range forecasts, the winter of 2016-17 was once again fairly mild across western and north central New York. Monthly temperatures averaged above normal during four of the five winter months, with the exception coming at the end of the season when March ended up being quite chilly. In fact, March proved to be colder than February, something that has happened only eight other times in recorded history at Rochester and just 10 times previously at Buffalo.

One would think that with such a mild winter that snowfall would be limited, but that was not necessarily the case. In fact, frequent lake snows early in the season helped the typical snow belts east of both lakes receive near to above normal snowfall for the season. Meanwhile, a lack of southwest flow lake effect events helped to starve the Niagara Frontier of much of their typical snowfall. Total snowfall for sites such as Buffalo, Batavia and Niagara Falls were as much as 2 to 3 feet below normal.

As we progressed through the autumn of 2016, there was increasing confidence that a weak ENSO would be in place across the Equatorial Pacific. This would either be in the form of a neutral event or a weak La Nina. In other words, sea surface temperatures for that region would be close to or slightly below normal. One of the teleconnections attributed to these conditions is a highly amplified longwave pattern over North America during the winter months. This type of pattern is climatologically favorable for frequent and possibly prolonged periods where arctic air is allowed to intrude southward into the eastern half of the United States, and in particular across the Great Lakes. While we did experience a small handful of arctic intrusions, especially in March, this was a far cry from what we typically experience even in a ‘normal’ winter.

In retrospect, the upper level pattern was much less amplified over the country than anticipated. Part of this was due to a strong and persistent East Asian jet that prevented the development of a significant West Coast ridge, and subsequent downstream trough over the eastern half of the country. This encouraged a ‘flatter’, more zonal upper level pattern that helped to block the southward progression of Arctic air while also keeping a feed of modified Pacific air in place. A closer inspection of low level temperatures reveals that mercury readings across the Canadian prairies and throughout much of the Canadian sub-arctic (Canadian Archipelago) were above normal as well, so the only source of true arctic air would have to come from cross polar flows. These patterns are rare during winters that feature strong west to east dominated jets (i.e. Low amplitude flows). In the end, this resulted in monthly 850mb temperatures that were as much as 5 degress C above normal across the Great Lakes region.

Another hemispheric teleconnection that often plays a major role in determining the severity of our winters is the North Atlantic Oscillation (NAO). This is especially the case during winters where a weak ENSO event is in place over the Equatorial Pacific, like this year.

During a negative NAO, a blocking ridge is found over Greenland and the North Atlantic. This encourages the development of a deep closed low over the eastern half of Canada which in turn circulates cold air southward into the Great Lakes region. This past winter though, while the typical Icelandic low was weaker than normal, there was a lack of substantial ridging over Greenland.

Interestingly, there is a strong teleconnection between ridging (or in this case a lack of troughing) over the eastern half of the United States and ridging found over western Europe. This certainly held true during the winter of 2016-17, as significant ridging was common over the far eastern Atlantic and western portions of Europe. This resulted in one of the mildest winters in recent memory for much of the British Isles, as well as France and Spain.

Monthly Highlights

November

November went down as a persistently mild month, except for one brief cold spell that gave the Genesee Valley to the southern Tug Hill region its first significant snowfall of the season.

Across Western New York, average temperatures for the month finished in the top 10 warmest, with records going back to 1871. East of Lake Ontario warm surges were less potent with November just a few degrees warmer than normal. The mild autumn also brought a later tree foliage change than normal to the region.

The Eastern Great Lakes region, like much of the Northeast U.S. had below normal precipitation this month. There were several moderate events across the region, but nothing extreme.

There were several notable weather events this month. The first was a long duration rain event, this on the 2nd and 3rd of the month when waves of rain along a weak, and slow moving cold frontal boundary passed across the region. For Western New York, 2-day rainfall totals amounted to around an inch, while east of Lake Ontario less rain was measured. The second event was the first significant lake effect snow event for the Lower Great Lakes. A deep area of low pressure slowly traveled across southern Quebec over the weekend of the 19th and 20th. This system transported Atlantic moisture over the Eastern Great Lakes that fed abundant moisture into bands of lake effect snow that fell southeast of the Lower Great Lakes on a cold northwest flow. Nearly a foot of snow fell in spots southeast of Lake Erie, while more widespread amounts of a foot to a foot and a half fell from the Genesee Valley to the Northern Finger Lakes region. Across the southern Tug Hill region upwards to two feet of snow fell from this system.

The third significant event this month was a strong cold front that passed across Western New York as the month of November closed. This front brought a quarter of an inch of rainfall to western and north-central New York by the close of the month, with a few scattered thunderstorms embedded across Western New York. Outside of these three events, there were a few storm systems that brought minor rainfall amounts.

December

A persistent northwest flow this month brought frequent winds across the Lower Great Lakes. The bulk of the wintry weather came mid-month when a deep, but not extreme, arctic air mass dropped across the region with winter's chills and persistent lake effect snow.

The first few hours of December remained very mild with temperature readings in the upper 40s to lower 50s across the region. A cold front swept through the region during the morning hours of the 1^st. The colder air that followed generated lake effect rain and snow showers. It would not be until a stronger cold front passed on the 8th that heavier and prolonged bands of lake effect snow formed east of the Eastern Great Lakes.

The first major lake effect event for the month began during the early morning of the 8th as much colder air deepened over the eastern Great lakes. This event primarily blitzed Ski Country and the Southern Tier with heavy snow. Almost three feet of snow fell during this event. A northwest flow also brought several inches of snow across the southern shores of Lake Ontario and inland across the Genesee Valley. East of Lake Ontario a foot of snow fell across the southern Tug Hill region. As this event drew to a close, the band of snow lifted northward towards Buffalo, and though in a weaker state it did drop 5 to 6 inches of snow across the metro Buffalo area late on the 11th and through the early morning hours of the 12th. Much of the snow ended by the morning rush hour of Monday the 12th for Buffalo.

On the heels of the first major event this month, a second event formed east of the Great Lakes. This event on a westerly flow focused the highest snow totals east of Lake Ontario. Initially a southwest wind ahead of an arctic air mass brought lake effect snow across metro Buffalo and towards Rochester, and then also towards Watertown during the afternoon hours of the 14th. Snow piled up quickly, impacting the afternoon and evening commute. Snow piled up towards 10 inches across Metro Buffalo before winds shifted the bands of snow southward towards the Southern Tier, and then the southern Tug Hill off Lake Ontario. An arctic front slowly dropped southward over Lake Ontario during the day and evening hours of Thursday the 15th. Strong winds off Lake Ontario combined with heavy snow brought blizzard like conditions to the southeastern shoreline of Lake Ontario, with Rochester receiving a daily record amount of snow of 10.6 inches. Bands of snow off both lakes lifted back northward, with a snow band off Lake Erie still going strong through Friday afternoon and producing another 6 inches of snow across Buffalo, including a snowfall rate of 3 inches per hour.

Between these two events, and a lake effect event to close out the year, a minor but impactful freezing rain event glazed much of Western New York Saturday night through Sunday morning the 18th. This glaze brought numerous accidents Saturday evening through Sunday morning across Western New York.

Finally as the year closed out, a third lake effect event unfolded across Western New York. This event over the final days of the month produced one to two feet of snow across southwestern New York State, while closer to Buffalo just several inches of snow fell.

Winds this month were gustier than normal with many areas having one of the windiest months in the past decade.

January

January 2017 will be remembered for its complacency as only brief periods of true winter weather occurred. Overall temperatures were well above normal, and snowfall was lacking. A persistent warm and moist air mass mid-month brought several days of fog and low clouds across Western New York, especially south of Lake Ontario.

January opened the New Year quiet with temperatures rising to above freezing. A warm front lifted across the region on the 3rd, spreading rain across the region but with minor flooding. A cold front swept across the region during the early morning hours of the 4th, sending the region into its only prolonged cold spell this month and generated lake effect snow east of the lakes. Lake effect snow flew east of the lakes from the 4th through the 8th, which brought snowfall accumulation across the Chautauqua ridge and the Boston Hills to 3 feet. Three feet of snow also fell from near the Jefferson and Oswego County line, to near Hooker in Lewis County. After 5 days with below normal air temperatures, a warm front lifted towards the region. Initially this front brought snow to the region, but as temperature warmed aloft, a wintry mix of sleet and freezing rain mixed in with the snow across New York on the 10th and 11th. A wave of low pressure produced widespread rain on the 12th, with an inch to an inch and a half of rain falling across the Southern Tier and towards the Lower Genesee Valley. Rain of this amount produced some flooding of both rivers and area-wide ponding of water. From the 17th to the 23rd air temperatures remained above freezing. There was a rain event on the 17th that produced a half to one inch of rainfall across the region, though with much of the snow melted from an earlier rain event, flooding was minimal. The warmer temperatures and at times northeast winds produced a period of low clouds and stratus south of Lake Ontario. Clouds and visibilities tended to be lowest from the evening, through the overnight and into the morning hours of the 20th through the 23rd.

Tranquil conditions started the 4th week of the month but a marginally cold air mass brought the second significant lake effect snow event to the region, dumping upwards of a foot and a half of snow across Southwest New York State, and near three feet of snow across the Tug Hill Plateau.

February

February 2017 will go down as the warmest February on record for our two climate stations of Buffalo and Rochester in Western New York, while Watertown and the Eastern Lake Ontario region did not always receive the warm winter air masses, and finished within the top 5 warmest Februaries on record. This warmth is just two years after the coldest February of all-time was recorded. This February also established the warmest February day on record.

A clipper system passed across the region to start the month, with snow and a little lake effect snow. A few rumbles of thunder occurred near the Buffalo Airport within this snow on the 1st. Dry air limited the snow east of Lake Erie, with just a half a foot of snow falling in spots well to the south of Buffalo. East of Lake Ontario where moisture was deeper and air temperatures slightly colder and more unstable, a foot to a foot and a half of snow fell across the Tug Hill region.

A second push of arctic air triggered another round of lake effect snow from the 2^nd through 4^th of the month. Similar to the event a few days earlier, the higher snowfall was measured east of Lake Ontario where four feet of snow was measured on the Tug Hill, yet not even a foot of snow was measured east of Lake Erie. A northwest flow on the 9^th and 10^th of the month produced a narrow, yet impactful band of snow just to the east of Rochester. A foot and a half of snow was measured in a narrow strip across Wayne and Cayuga Counties. Another minor lake effect snow event, the fourth of the month, unfolded on the 15^th and 16^th of the month with a half to one foot of snow falling east of the lakes. Upstream connections and orthogonal upslope flow aided in the final snow tallies as lake effect snow parameters were weak.

The remainder of the month saw mild air become plentiful, with just three days after the first week of the month dropping to or below normal. From Saturday, the 21st to a week later on the 28th temperatures rose to well above normal. Highs in the 40s and 50s eventually peaked in the lower 70s across the region. This set the warmest February day on record for many of our climate sites.

March  

March came in like a lion, as a storm system cut by Western New York to the northwest. This system brought wind gusts over 50 mph to the Niagara Frontier. Warm air ahead of the surface low also brought temperatures into the lower 60s across western and north central New York State. However this warmth fleeted quickly, replaced by subfreezing temperatures for the next several days. The coldest morning this month occurred on the 5^th.

After a return to mild temperatures the 6th through 8th, a severe wind event occurred across the western half of the state on Wednesday the 8th. This wind event was not a classic event as the surface low remained far away from the Eastern Great Lakes region. Rather a very strong low level jet flowed across the region, with sunshine increasing the mixing layer, such that these strong winds aloft were transported to the surface. The nearby cooler Lake Erie waters actually sheltered the metro Buffalo area from the brunt of this event, while inland the damage was much more severe. A wind gust registered at 81 mph at Rochester was the second strongest wind gust ever recorded at this site.

The following Tuesday and Wednesday, the 14th and 15^th of March, a nor'easter developed, producing widespread snow across the region. Though the initial round of snow was manageable, the constant moist, northerly flow across Lake Ontario and falling temperatures brought continual lake enhanced snow, such that by time all was said and done on the 15^th close to two feet of snow was recorded along the southern shoreline of Lake Ontario. The snow depth decreased rapidly, thanks to a strong March sun angle and daytime temperatures rising above freezing. This snow ablated just a week later, before several rain events impacted Western New York. This first event brought nearly an inch of rainfall to Western New York on the 24th and 25th. A second event, with greater rainfall, reached the region at the end of the month with one to one and a half inches of rain falling across Western New York.

April

After a cool March, April returned to seasonable temperatures with Spring returning to Western New York. The last widespread snow event of the winter season occurred on the 6^th and 7^th with several inches of snow falling. From here on out the majority of precipitation events for the remainder of the month were plain rain.