Winter Summary 2018-2019

Winter Summary 2018-19

The winter of 2018-19 was manageable, with near to above normal snowfall and fluctuating temperatures that finished the winter season at or just below normal across Western and North Central New York. Overall the winter season did not fair much different from the previous season.  The winter season began with below normal temperatures in November, and within this cold regime the season started much snowier than normal. A mild December and below normal snowfall eroded the early winter snowpack.  The heart of the winter season occurred in January with several large snow events that brought a deeper snowpack to portions of Western and North Central New York. A quiet February and March finished the winter season.

Temperatures alternated between below and above normal through the winter season, with November, January and March below normal for most areas. November’s temperature strayed the most from normal, and through the winter there only a handful of temperature records at the primary climate sites.

The 13 lake effect snow events this season was 3 more than normal. There were 4 lake effect snow events each in the January and February months.  There were two blizzard events this winter. The first blizzard event occurred across Erie, Wyoming and Genesee counties, as well as across Jefferson and Lewis Counties on January 30^th. The second event occurred February 24^th and 25^th across counties east of Lake Ontario.

Despite the fluctuating temperatures there was little ice jam flooding across the region this winter. There were several Lake Erie seiche events deep into the winter season that sent ice over the ice boom and creating flooding along the immediate Niagara River. Lake Erie froze January 23^rd, just a few days past normal and then thawed with ice out of the Lake near Buffalo on April 29^th which is about two weeks past normal.  

Snowfall

Snowfall for the winter of 2018-2019 was well above normal for some areas such as Buffalo and Watertown, but near to slightly below normal for other areas such as Rochester. Generally areas just east or northeast of either Lake Erie or Lake Ontario experienced above normal snowfall for the winter, with some areas like Buffalo and the Watertown area having two feet or more above normal snowfall for the season. Areas south of the lakes or farther inland from the lakes received near normal snowfall with a few locations having well below normal snowfall. With 118.7 inches of snow, Buffalo had its 12^th snowiest winter on record and was 24 inches above the normal of 94.7 inches. With 96.8 inches of snow, Rochester was slightly below the 99.5 inch normal for the season. The 118.7 inches of snow for the winter of 2018-2019 at the Buffalo Airport ranks as the second snowiest winter in the last decade and fourth snowiest winter since the winter of 2000-2001.

The pace for the above normal snowfall that did occur in some locations was started in November 2018 when most locations across the Buffalo forecast area received well above normal snowfall for November. December 2018 was the only month of the winter where snowfall was below normal for all climate and Cooperative Observer locations. Many areas received less than half the normal snowfall expected in the month of December, resulting in some of these areas having below normal snowfall amounts for the winter. January and February 2019 for most areas was near normal snowfall levels. The exception being well above normal snow amounts in January northeast of Lake Erie and Lake Ontario, primarily due to a large lake effect event with blizzard conditions at the end of the month. Snow totals for the season were generally above normal in the lake effect areas and below normal elsewhere. This was primarily due to a repetitive feed of the very cold air into the nations mid section and Upper Great Lakes that later moved into our forecast area. Direct shots of arctic air into the Lower Great Lakes are more favorable to multiple band events that cover a larger area versus larger snowfalls in the lake snow-belts. 

Temperatures

Temperatures for the winter of 2018-2019 were near normal for all three climate locations and most of the Buffalo forecast area. Buffalo and Watertown were slightly colder than normal at 1.1F and 0.7F below normal respectively. Rochester was 0.1F above normal for the winter. Temperatures at all three climate locations for November 2018 ran between four to five degrees Fahrenheit below normal. Temperatures in December 2018 were between three and four degrees Fahrenheit above normal for Rochester and Buffalo, while Watertown was one degree above normal. Temperatures for the three climate locations for the rest of the winter were within a few degrees Fahrenheit of normal.

Winter Statistics for Buffalo, Rochester and Watertown

Buffalo

Average Temperature, November – March: 30.1F (1.1F below normal)

Snowfall: 118.7” (12^th snowiest)

Days with 1.0” or more of snowfall accumulation: 31

Days with 1” or more on ground: 67

Rochester 

Average Temperature, November – March: 31.3F (0.1F above normal)

Snowfall: 96.8” (42^nd snowiest)

Days with 1.0” or more of snowfall accumulation: 29

Days with 1” or more on ground: 80

Watertown

Average Temperature, November – March: 24.5F (0.7F below normal)

Below are tables for temperature records set at the three climate locations for the winter of 2018-2019.

Buffalo

Rochester

Watertown

  Hemispheric Pattern

The Winter of 2018-19 was not especially cold, nor snowy, for the bulk of western and north central New York. That being said, an unusually transitory polar vortex and a weak to moderately strong El Nino did allow for chunks of arctic weather to sweep across the northeast U.S. This helped to support above average snowfall in the lake snow belts. All in all though, given the strength of the ENSO (El Nino Southern Oscillation) in the Equatorial Pacific, our winter turned out to be about what was expected (see below).

Throughout the Fall and early Winter, the Climate Prediction Center was forecasting a weak to moderately strong El Nino event. While the forecast was fairly consistent through the period, there was a high degree of spread between the various ensembles that make up the final forecast. This led to a little more uncertainty in the forecast strength of the El Nino event. This is important to note because weaker ENSO events favor high amplitude patterns over North America, so not having a high confidence in the overlying jet pattern will severely limit the ability to forecast temperature patterns. A higher amplitude flow would support arctic intrusions south of the international border and thus favor colder weather. On the other hand, strong El Nino events often result in a more zonal flow that floods the country with milder, Pacific modified air. As it turned out, the ENSO event was probably just strong enough to prevent us from having a memorable season.

As we opened the ‘cold weather season’, there was a somewhat ominous pattern in place across North America. A strong, persistent ridge was in place along the Pacific coast of the continent, while a deep trough was anchored over the eastern half of Canada. This supported a seven week stretch where temperatures averaged well below normal to start the season. Bouts of snow came early and often, particularly during the second half of November when the highly amplified flow encouraged parts of western New York to receive snowfall that averaged more than a foot above normal. Interestingly, anecdotal evidence from past winters with similar ENSO events included cold, snowy starts that later transitioned to a prolonged period of relatively mild weather.

As we pushed deep into the heart of December though, an intense East Asian jet with winds approaching 200 kts over the northern Pacific helped to batter down the staunch ridge that had dominated the west coast of North America. Meanwhile, the polar vortex eased across the Pole to the Russian waters of the Arctic Ocean.  This noteworthy hemispheric pattern change not only served to cut off the source of cold air into the Lower 48, but it allowed Pacific modified air to eventually reach to the Lower Great Lakes where temperatures averaged above normal for four solid weeks, including the holiday season.

By the second week of January, a weak Greenland block supported the development of an upstream closed low over eastern Canada. This encouraged the polar vortex to move back to THIS side of the Pole where it took up residence in the vicinity of Hudson Bay. The strong cross polar flow generated between this high latitude closed low and the re-emergence of the west coast ridge allowed arctic air to pour southward into the Great Lakes region where we experienced the coldest weather of the winter season. Even though this was climatologically the coldest part of winter, temperatures STILL managed to average more than 20 deg F below normal on a fairly routine basis. This would be comparable to having daytime temperatures frequently reach the 100 degree mark for a large stretch in July. The highlight of this pattern change was a lake effect driven blizzard over the Niagara Frontier directly supported by the polar vortex over Hudson Bay.

The overall hemispheric pattern was fairly persistent through the month of February. A broad trough was based along the Canadian border with a near zonal flow found further to the south over the Lower 48. While there was a substantial ridge off the west coast, its axis was centered at least 1000 miles further out in the Pacific. This all led to very changeable weather across the Lower Great Lakes, as temperatures experienced a roller coaster ride that included no fewer than six air mass changes. Despite the variation in temperatures though, mercury levels averaged well above normal for the month.

March fell right in line with the trend of alternating cold and mild months, as the ridge over the eastern Pacific repositioned itself along the West Coast. This promoted a re-amplification of the general jet stream over the continent so that the door could once again be opened for cold air to move south from Canada. The majority of the month averaged below normal…dashing the hopes of an early Spring.

  Monthly Highlights

November

Following a cold end to October the month of November continued the theme of cool and damp days. Outside of a few short-lived warm spells, below normal temperatures characterized the month. Snow averaged above normal for the month, with both lake effect and synoptic systems bringing accumulating snow to western New York.

Temperatures averaged 35.5F at Buffalo and 36.4F at Rochester for the month, making this particular November the 11^th and 17^th coolest November on record at the respective sites. The warmest temperature this month was 62F degrees on the 6^th, which occurred during a brief warm spell. There were 27 days that remained below 50F at Buffalo…which is the greatest on record since records moved to the airport in 1943. On November 22^nd, Thanksgiving, the temperature before midnight dipped to 9F at Buffalo and 7F at Rochester. This was the coldest Thanksgiving temperatures on record for both sites! At Rochester, the mercury then dipped to 4F by daybreak of November 23rd, a temperature that has never been recorded that early in the season.

Precipitation for November averaged well above normal. In fact, there were only two days without measurable precipitation at Rochester and four at Buffalo. This included 9 days of measurable snowfall at Rochester…more than double the normal and the greatest number since 1995.

A frontal boundary stalled across western New York to start November, and this front helped to produce a soggy start with a solid inch and a half to two inches of rain. Following a brief warm spell, a cold frontal passage on the 8^th initiated a period of below normal temperatures that lasted through the 24^th. During this period, there were several snow events, including the first notable lake effect snow on the 10^th and 11^th and the first widespread synoptic snow on the 15^th and 16^th. In both cases, the higher terrain of the Southern Tier received the largest snowfalls of a foot to foot and a half. This snowfall melted off in the ensuing days, but it was quickly replenished by a prolonged northwest flow event that supported six inches of wet snow in the Buffalo metro area and two to three feet across the hill tops of the Southern Tier.

The strongest winds of the month occurred on the 6^th when gusts of 55 mph were recorded at Buffalo and 49 mph at Rochester…as a deepening storm system passed to the west of the region.

December

The first several days of the month were warm, but a strong frontal passage then allowed for a stretch of colder than normal weather from the 4^th through the 12^th. During this period, a lake effect event produced six inches of snow for the Buffalo metro area and less than three inches for Rochester. Milder weather then returned for the bulk of the remainder of the month. This severely limited snowfall across the entire region, as December is one of the top two months for significant lake snow events. Temperatures generally averaged 3 to 4 degrees Fahrenheit above normal for the month. While these readings were not close to any records, it was a sharp contrast to the previous month where mercury readings averaged 5 to 6 degrees Fahrenheit BELOW normal.

As alluded to, snowfall across the region averaged well below normal for the month. The Buffalo and Rochester metro areas received close to a foot of snow for the month, which was half that of normal. The anomalies were even more striking in the lake snow belts where snowfall departures were as much as 75% below normal.  

The only significant weather event for the month occurred on New Years Eve, when a storm passing to the west generated damaging wind gusts in excess of 55 mph.

All in all, it was a mild month with snowfall that averaged well below normal.

January

January started where December left off, with bare ground in most areas and well entrenched in a regime of mild weather. Old Man Winter did finally return to the region by the middle of the month as significant snowfall and arctic cold became common. This included a blizzard over parts of far western New York.

While temperatures averaged WELL above normal (9 degrees Fahrenheit) for the first week and a half of the month, only a handful of days could climb above normal for the remaining three weeks or so. In fact, it became progressively colder as arctic air seemed to find a new home over eastern Canada and Lower Great Lakes. Several days featured temperatures that dropped below zero. The very cold end to the month of January promoted shoreline ice on both Lakes Erie and Ontario.  

January was very unsettled with precipitation averaging above normal throughout the region. In fact, the 5.71 inches of precipitation (liquid equivalent) at Buffalo was the 7^th highest for January on record. As one might expect given the cold bias to the month, the bulk of the precipitation fell as snow. Over 63 inches of snow fell on Buffalo, ranking as the 4^th snowiest January on record. Much of this snow fell on the 25^th when one to two feet of lake snow fell northeast of Lake Erie. This was followed by the largest event of the month, a blizzard that struck the Buffalo area in the wake of an arctic cold front on the 29^th and 30^th. Powerful winds whipped up whiteout blizzard conditions across the region with wind chill values plummeting to between 25F and 30F below zero. In Rochester, nearly 8 inches of snow fell on the 19^th, breaking a 135 year old record (6.3” in 1884). 

In summary, after a warm start to the month, January featured a fury of storms with a frigid ending.

February

February was a very active month with winter storms generating ice, wet snow and strong winds across the region. While it was a changeable month with notable swings in temperatures, the month averaged just above normal. This guaranteed that ‘climatological winter’ (Dec-Feb) would average above normal.

In regards to precipitation, liquid equivalent for the month was about an inch above normal. Nearly half of this fell as just plain rain…giving the region a much needed respite from the heavy and frequent snows from January. The only two snow events of note fell on the 12^th-13^th and on the 27^th-28^th when general six inch accumulations were reported. Otherwise rain and mixed precipitation events were common. One of the most significant snow events took place on the 13^th when strong winds of 40 to 55 mph during a snowfall resulted in considerable blowing snow, particularly in open rural areas where near blizzard conditions were experienced.

Without question, the most memorable event of the month occurred from the 24^th till the 26^th when a powerful and prolonged wind storm impacted the entire region. In the wake of a cold frontal passage during the midday of the 24^th, an intense cyclone (970mb at peak) taking a ‘classic high wind track’ through southern Ontario produced widespread wind gusts of 60 to 70 mph with isolated gusts to 80 mph. This brought down numerous trees, damaged house sidings and roofs, and generated a prolonged lake seiche to 8.5 feet on Lake Erie. 

In all, February was an active month that featured above normal temperatures and unimpressive snowfall totals.

March

Winters grip on western New York continued into the beginning of March, with lake effect snows and relatively low temperatures. Besides the typical strong winds of this transition month, there were no extremes in temperatures or precipitation.

Temperatures for the month averaged at least 2.5F degrees below normal for both Buffalo and Watertown, with readings some 0.8F degrees below normal at Rochester. This was the 7th March this decade that averaged below normal in the temperature department. Meanwhile precipitation averaged below normal throughout the region, and being a relatively ‘mild’ month, this translated into below normal snowfall as well.

March started off with a deep upper level trough over the Great Lakes region. While this pattern supported below normal temperatures, there were generally just nuisance lake snow events. A storm system that passed to the west on the 10th brought a widespread soaking rain to the region, elevating stream flows while also creating damaging wind gusts. Spring-like temperatures then arrived on the 13th through 15th with the mercury in many areas topping out between 65 and 70. This was the warmest day across the region since mid October.

April

April featured a variety of Spring-like weather, with nuisance wet snow accumulating near the beginning and end of the month. In between, several pleasant warm ups allowed the mercury to climb into the 70s for the first time across parts of the region along with the first severe thunderstorm outbreak with large hail and damaging winds in the Genesee Valley and across the Southern Tier.

While temperatures for the month averaged within a degree of normal, areas east and northeast of both lakes experienced notably cooler weather from a persistent southwest flow. Since snowfall records began in the late 1800’s, every April month has had LEAST a trace of snow, and this month was no exception. Precipitation averaged close to normal with total snowfall generally under a few inches. The bulk of the April snows fell during the first few hours of the month when Rochester received a couple inches and Buffalo just a half inch.

Overall though, this was a fairly typical month of April with thunderstorms highlighting the clash between late winter chill and early summer warmth.