Heat in Pennsylvania, December 1 to 7, 1998

A very strong and persistent ridge of high pressure at all levels of the atmosphere remained anchored across the western Atlantic Ocean and the Middle and South Atlantic States from November 28th through December 7th. The result was 10 consecutive days of record breaking, unseasonably warm weather across Eastern Pennsylvania. Many locations set new all-time monthly record high temperatures for December. The warmest days were December 4th and 7th. The highest temperatures included 77 degrees in West Chester (Chester County), at the Willow Grove NAS (Montgomery County) and the Northeast Philadelphia Airport, 76 degrees in Pottstown (Montgomery County) and Neshaminy Falls (Bucks County), 75 degrees in New Hope (Bucks County), 74 degrees in Chadds Ford (Delaware County), 73 degrees at the Philadelphia International Airport and 72 degrees at the Lehigh Valley International Airport. The high temperatures of 73 degrees at the Philadelphia International Airport on both the 4th and the 7th not only set new daily high temperature records, but also established a new record for the month of December. The previous monthly record was 72 degrees and was set on December 29, 1984 and December 7, 1951. A new daily high temperature record also occurred on the 6th (69 degrees) at the Philadelphia International Airport. At the Lehigh Valley International Airport, the daily high temperature record was tied on the 2nd (63 degrees) and new daily record highs were set on the 3rd (66 degrees), 4th (72 degrees) and the 7th (71 degrees). The high temperature of 72 degrees on the 4th tied the all-time monthly record previously set on December 29, 1984. In a paradoxical scene for early December, people were buying Christmas trees with shorts on. A cold front moved through the region late in the day on the 7th and dropped temperatures closer to normal levels.