Heat in Pennsylvania, August 1, 1999

A protracted run of days with consecutive high temperatures of 90 degrees or higher began on July 23rd in Southeast Pennsylvania. It lasted as long as 16 days near the Maryland border through August 7th. Dispersed within this run were two periods of both excessive heat and humidity: from July 23rd through July 25th and again from July 29th through August 1st. There were nine heat related deaths during this hot spell, four in July and five in early August. Eight of the deaths occurred within Philadelphia and one in Delaware County. A strong cold front moved through the region the afternoon and evening of August 1st. This brought in considerably drier air, the driest air since mid-July. Because of the extremely dry ground conditions, diurnal temperature ranges remained larger than usual. High temperatures reached into the 90s in some areas through August 7th. That day a stronger cold front moved through and coupled with cloudy skies and light rain on the 8th brought an end to the string of consecutive days with high temperatures of 90 degrees or higher. The string of 12 consecutive days with high temperatures of 90 degrees or higher at Philadelphia International Airport was the longest since the summer of 1995. There were nine heat related deaths during this run of oppressive weather, four occurred in July, five in August. The five heat related deaths in August all occurred within Philadelphia. In most instances the persons were found in their homes with inadequate ventilation and no air conditioning. The continued excessive heat and lack of rain parched non-irrigated farms across the state. Throughout the summer there were 87 heat related deaths in Eastern Pennsylvania: 1 in May, 3 in June, 78 in July and 5 in August. In Philadelphia there were 67 heat related deaths. For most places the highest temperatures during this hot spell occurred on July 28th and July 31st. They included 102 degrees in Valley Forge (Chester County), 101 degrees in Hamburg (Berks County), Sellersville (Bucks County), and Easton (Northampton County), 100 degrees in Pottstown (Montgomery County), Reading (Berks County) and in the Franklin Institute within Philadelphia, 99 degrees at the Philadelphia and Lehigh Valley International Airports, Bath (Northampton County) and Morgantown (Berks County), 98 degrees at the Northeast Philadelphia Airport and Doylestown (Bucks County), 97 degrees at the Willow Grove NAS (Montgomery County) and East Stroudsburg (Monroe County) and 96 degrees in West Chester (Chester County). The Poconos offered some relief from the heat has high temperatures occasionally failed to reach 90 degrees during this 16 day period, especially in the higher terrain.