Record warmth prevailed in the East this week as colder air was kept at bay.
Daily record highs were set in Philadelphia, Buffalo, Cleveland, New York City, Washington, D.C., and many other locations. As the mild air persisted through Tuesday, Philadelphia and New York City each set a record high for the fourth consecutive day. At one point on Monday, it was warmer in Buffalo, New York, than in Phoenix.
"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.
While warmth gripped the Midwest and East, cold air became entrenched across the West, with record low temperatures being challenged.
Los Angeles tied the record of 40 F on Wednesday, which was originally set in 1944 and tied in 1948 and 1971. It fell to 15 F in Douglas, Arizona, breaking the record of 18 F from 1999.
Many parts of the West, Plains and Upper Midwest were blanketed by a snowstorm through midweek along the leading edge of cold air.
Parts of Utah, Arizona, Wyoming and Montana received snow on Monday, with Salt Lake City receiving its biggest snowfall this season. With 6.6 inches measured at Salt Lake City airport, the city set a new record for Dec. 14. Hundreds of accidents and slide-offs were reported by state troopers in Utah, the Associated Press reported.
Cheyenne, Wyoming, and East Rapid City, South Dakota, each broke 100-year-old snowfall records on Dec. 15. Cheyenne received 7 inches, breaking the record of 3.3 inches set in 1892. East Rapid City received 5.5 inches, breaking the record of 1.8 inches set in 1908.
A massive storm barreled through the western Aleutian Islands last weekend, lashing the islands with hurricane-force winds. A 122-mph (196 km/h) wind gust was recorded at Adak Island, Alaska, on Saturday night.
The storm tied the record for strongest storm to impact the region. A little over a year ago, ex-Super Typhoon Nuri crossed Dutch Harbor, Alaska, which is located in the Aleutian Islands, with a central low pressure of 924 millibars (27.29 inches of Hg).
Powerful Typhoon Melor slammed the Philippines this week, resulting in at least 11 deaths, according to Agency France-Presse.
The storm, recognized as Nona in the Philippines, made four landfalls across the country this week, but the first occurred on Monday over Bulusan, Sorogon, in southern Luzon at 4 p.m. local time. At the time, Melor was the equivalent of a Category 4 hurricane.
Ahead of the storm, more than 740,000 were evacuated in northern Visayas and southern Luzon, the Philippines government said. As Melor diminished, Tropical Rainstorm 29W, known as Onyok in the Philippines, became the latest threat to the country.
Severe thunderstorms rumbled across Australia on Wednesday, bringing large hail, wind damage and flooding. The storm even spawned a large tornado near Sydney, one of Australia's largest cities.
Several AccuWeather meteorologists and staff writers contributed content to this article.