Heat in Pennsylvania, July 28 to 30, 2002

Another hot and very humid air mass moved into Eastern Pennsylvania on the 28th. In most areas this hot spell produced some of the highest heat indices of the summer as they reached near 105F and between 105F and 110F in Philadelphia during the afternoon of the 29th. A cold front moved through the region during the night of the 30th. While temperatures on the 31st still reached into the 90s, dew point temperatures and the moisture content of the air mass was considerably lower. The apparent temperature (or heat index) matched and did not exceed the afternoon high temperature. More humid air again moved in during the start of August. The string of days with high temperatures of 90 degrees or higher did not end until August 5th or 6th. There were two reported heat related deaths. In Montgomery County, a 54-year-old male contractor was found lying unconscious on the ground outside a house he was working on. He later died. A 79-year-old woman was found dead in Lansdale. All the windows in her residence were closed and she had no fan or air conditioning. In Philadelphia, an 87-year-old woman perished. The hot weather and high humidity levels taxed electric utilities and the PJM Interconnection issued a usage advisory.For most places the highest temperatures with the July part of this hot spell occurred on the 29th and included 101 degrees at the Franklin Institute within Philadelphia, 100 degrees in Crum Creek (Delaware County), 98 degrees at the Philadelphia International Airport, West Chester and Valley Forge (Chester County) and Neshaminy Falls (Bucks County), 97 degrees in Reading (Berks County) and Bath (Northampton County), 96 degrees in Pottstown (Montgomery County), Lehighton (Carbon County) and Perkasie (Bucks County), 95 degrees at the Lehigh Valley International Airport and Doylestown (Bucks County), 94 degrees in Morgantown (Berks County) and 93 degrees in East Stroudsburg (Monroe County).The hot spell at the end of July cemented the month as being well above normal. Monthly mean temperatures averaged about 2 degrees warmer than normal. The July monthly mean temperature at the Philadelphia International Airport was 79.6 degrees, 2.0 degrees above normal and the 11th warmest July on record. There were 17 days that the high temperatures was 90 degrees or higher. The July monthly mean temperature at the Lehigh Valley International Airport was 75.6 degrees, 2.3 degrees above normal. There were 14 days that the high temperatures was 90 degrees or higher. The July monthly mean temperature in Reading was 77.1 degrees, 2.5 degrees above normal. There were 16 days that the high temperatures was 90 degrees or higher.