Record warmth built across much of the eastern United States this past weekend, breaking record highs dating back to the 1800s.
For much of the East, high temperatures ranged between 20 and 30 degrees Fahrenheit above average last weekend. Temperatures that high are more typical of October.
Not only were high temperatures broken this weekend, but also numerous record high minimum temperatures.
Lexington, Kentucky, broke a record-high temperature on Saturday dating back to 1873.
|Saturday, Dec. 12||New Record (F)||Old Record (F) (Year)||Sunday, Dec. 13||New Record||Old Record (Year)|
|Greenwood, Miss.||83||79 (1972)||Washington-Dulles Arpt.||73||71 (1984)|
|Norfolk, Va.||77||76 (2007)||Danville, Va.||73||70 (1985)|
|Georgetown, Del.||74||68 (1971)||Evansville, Va.||71||70 (1918)|
|Paducah, Ky.||73||66 (1991)||Philadelphia, Pa.||71||65 (1923)|
|Louisville, Ky.||73||67 (2007)||Islip, N.Y.||68||60 (1990)|
|Evansville, Ind.||72||68 (1948)||Newark, N.J.||68||63 (1946)|
|Joplin, Mo.||72||69 (1907)||Allentown, Pa.||68||62 (1923)|
|Cape Girardeau, Mo.||71||65 (1991)||New York-Central Park||67||64 (1923)|
|Atlantic City, N.J.||71||67 (1931)||Flint, Mich.||65||55 (1991)|
|Frankfort, Ky.||71||68 (1931)||Harrisburg, Pa.||64||63 (1948)|
|Cleveland, Ohio||70||63 (1949)||Williamsport, Pa.||62||61 (1901)|
|Springfield, Ill.||70||64 (1929)||Detroit, Mich.||62||60 (1881)|
|Lexington, Ky.||70||68 (1873)||Binghamton, N.Y.||62||56 (1984)|
|Beckley, W.Va.||69||66 (1911)||Milwaukee, Wis.||60||58 (1975)|
|Peoria, Ill.||68||62 (1991)||Dubuque, Ioqa||60||55 (1920)|
A persistent weather pattern set up for much of the month thus far, leading to mild air to surge across the Eastern states.
"The warmth in the East last weekend was set up by a very strong jet stream that lifted well north of the eastern United States," AccuWeather Meteorologist Evan Duffey said.
The jet stream is a narrow zone of strong winds in the upper levels of the atmosphere that helps to steer weather patterns. The jet stream also tends to separate the cold air to its north and warm air to its south.
High pressure over the southwest Atlantic Ocean generated southerly winds over the weekend, pumping in warm air from the equatorial region across the East.
A stretch of sunny and dry conditions also contributed to temperatures rising to record values.
An east wind across portions of New England, including Boston, this weekend allowed temperatures to stay below record values. Regardless, high temperatures were still 10-20 degrees above average.
The lack of a snowpack allows temperatures to rise much quicker during the daytime compared to a snowpack in place.
The lack of any winterlike chill across the East has not been uncommon for the past couple of months. The month of November was one of the warmest months on record for many Eastern cities. This unseasonably warm pattern has continued right through the beginning of December.
Through the first half of December, temperatures from the East Coast to the Plains have averaged above normal for the month. Some locations are close to 20 degrees above normal for the month.
Temperatures in International Falls, Minnesota, have averaged about 19 degrees above average for the month through Dec. 13. The city has had only one day with a high temperature below 32 F and only three days with a low temperature in the teens. High temperatures are typically in the low 20s with overnight low temperatures in the single digits.
A mild week will keep temperature departures well above normal through the third week of December.
"Until the jet stream sinks to the south, temperatures will remain well above normal," Duffey said.
While temperatures will lower slightly for much of this week, the first true taste of winter will build across the region late this week and into the weekend.
The first true shot of winterlike air will advance from the Plains on Thursday to the East Coast into the weekend.
Temperatures across much of the East will be below normal for the weekend.
"There is the potential for another significant warmup in the eastern U.S. toward Christmas," AccuWeather Meteorologist Michael Doll said.