A wicked cold blast of January-like Arctic air is smashing records as it pours southwards over the eastern two-thirds of the United States, with temperatures 15 - 35°F below average common on Tuesday morning across much of the country. Freezing temperatures pushed all the south into the Florida Panhandle, where Pensacola
hit 28°F. The cold air flowing over the unfrozen waters of the Great Lakes has unleashed an epic lake effect snow storm in the lees of Lake Erie and Lake Ontario, where the west-southwesterly winds of the storm have aligned with the long axis of these lakes, allowing the air to pick up large amounts of moisture. Figure 1.
Lake effect snow storm over Buffalo, New York at 7:53 AM EST November 18, 2014. Image credit: Mark T. Branden
via Twitter.Figure 2.
Radar image of lake effect snows affecting all five Great Lake at 9:30 am EST November 18, 2014. Image taken from our wundermap.Hardest hit: Buffalo, New York
A Lake Effect Snow Warning is in effect for Buffalo, New York
, where areas just south and east of the city had received over three feet of snow by Tuesday morning. As of 10:15 am EST Tuesday, the Buffalo suburb of Lancaster
on the city's east side had received an amazing four feet
of snow in 24 hours, with snowfall rates of 4" per hour and occasional rumbles of thunder. With the band of heavy lake effect snow responsible not expected to move much through Tuesday night, the NWS is forecasting
that Lancaster will receive a total of nearly six feet
of snow before the winds shift by Wednesday morning. A state of emergency has been declared in Erie County, New York, which includes Buffalo. All travel except for emergency vehicles is banned, and a 13-mile section of the New York State Thruway (Interstate 90) was closed from the east side of Buffalo southward. To avoid traffic backups, a 37-mile stretch of the Niagara Thruway (I-90) southbound from Niagara Falls to the I-90 interchange was also shut down on Tuesday morning.Figure 3.
Open your door…and see winter! Those are cars out there under those giant snow humps. Image taken from the Park Lane Apartments in Buffalo, New York, on November 18, 2014. Image credit: Ben Oship, via Instagram.
Heavy snows are also piling up in the lee of Lake Ontario near Watertown, New York,
where over three feet of snow is expected. Lesser snow amounts are expected in the lees of the other Great Lakes, where the wind will not be blowing over such long stretches of open water. In the lee of Lake Michigan, up to 15" had fallen in northern Lower Michigan at Boyne Falls
by Tuesday morning.Figure 4.
Departure of temperature from average at 2 meters (6.6') as diagnosed by the GFS model at 00 UTC November 18, 2014. A sharp kink in the jet stream (Figure 4) allowed cold air to spill southwards out of the Arctic over the Eastern two-thirds of the United States. Compensating warm air flowed northwards into the Arctic beneath a ridge of high pressure over Alaska. Data/image obtained using Climate Reanalyzer™ (http://cci-reanalyzer.org),
Climate Change Institute, University of Maine, Orono, Maine.Figure 5.
Winds at a height where the pressure is 250 mb show the axis of the jet stream, seen here at 00 UTC November 18, 2014. A strong trough of low pressure was present over the Central U.S., and an unusually strong ridge of high pressure was along the U.S. West Coast. Data/image obtained using Climate Reanalyzer™ (http://cci-reanalyzer.org),
Climate Change Institute, University of Maine, Orono, Maine.An extreme jet stream pattern responsible
The intense cold blast is being triggered by an unusually extreme jet stream pattern, featuring a sharp ridge of high pressure along the U.S. West Coast and a deep trough of low pressure diving to the south over the Central United States. This configuration allows cold air to spill out of the Arctic behind the trough into the Central U.S., and be replaced by anomalously warm air flowing northwards along the West Coast of the U.S. deep into the Arctic. This extreme jet stream pattern is due, in part, to the influence of Super Typhoon Nuri, which caused a ripple effect on the jet stream after the typhoon became one of the most powerful extratropical storms ever recorded in the waters to the west of Alaska ten days ago. The extreme jet stream pattern will moderate by Friday, with near-normal temperatures expected across most of the U.S. by Sunday.
Wunderground's weather historian Christopher C. Burt has a post on the history of lake effect snowstorms, Lake Effect Snow Totals and Historical Perspective.
Some U.S.-record point snowfalls from the Great Lakes region from lake effect storms include:
12.0” in 1 hour at Copenhagen, New York on Dec. 2, 1966
17.5” in 2 hours at Oswego, New York on Jan. 26, 1972
22.0” in 3 hours at Valparaiso, Indiana on Dec. 18, 1981
51.0” in 16 hours at Benetts Bridge, New York on Jan. 17-18, 1959
77.0” in 24 hours reported in Montague Township on the Tug Hill Plateau of New York on Jan. 11-12, 1997