Winter Storm and Heavy Snow in Pennsylvania, March 6, 2003

A low pressure system that formed on a slow moving cold front brought heavy snow to the Poconos and a wintry transition from rain to sleet, freezing rain and then snow across most of the rest of Eastern Pennsylvania. Accumulations averaged around 6 inches in the Poconos, 1 to 3 inches in Berks County and the Lehigh Valley and an inch or less around the greater Philadelphia Metropolitan Area. Precipitation started as snow across most of the Poconos just before dawn on the 6th. It fell heavy at times from the middle of the morning into early afternoon. The snow ended during the early evening. Across the Lehigh Valley precipitation started as rain around 3 a.m. EST. As colder air moved into the system, precipitation changed to freezing rain during the morning commute and then to snow toward the end of the morning commute. Snow continued until it ended toward evening. The snow fell briefly heavy around Noon EST. In Berks County and the Philadelphia northwest suburbs, precipitation started as rain between 2 a.m. and 3 a.m. EST. It started to mix with and change to sleet during the morning commute from north to south. Precipitation then changed to snow during the second half of the morning. It mixed with sleet from time to time toward Philadelphia. Precipitation ended toward evening. In Philadelphia and Delaware Counties precipitation started as rain around 2 a.m. EST. Sleet started to mix in during the second half of the morning. Precipitation then changed to just sleet around Noon EST and then a mixture of light freezing rain, sleet and snow for the rest of the afternoon before it ended around 6 p.m. EST. Even though temperatures were below freezing, the indirect insolation from the sun kept most roadways in and around Philadelphia wet when the freezing rain fell. Ice accretions on exposed surfaces, mainly those with northern exposures, were less than one-quarter of an inch. The worst reported road conditions were in the Lehigh Valley where slick roads caused dozens of accidents. There were five collisions alone along Pennsylvania State Route 512 in Northampton County. Cars, vans, tractor trailers and mail trucks drove off roads. Specific snow and sleet accumulations included 8.3 inches in East Stroudsburg (Monroe County), 6.5 inches in Hamilton Township (Monroe County), 6.4 inches in Bossardville (Monroe County), 6.2 inches in Albrightsville (Carbon County), 6.0 inches in Pocono Summit (Monroe County), 3.0 inches in Easton (Northampton County) and Lehighton (Carbon County), 2.5 inches in Forks Township (Northampton County), 1.8 inches at the Lehigh Valley International Airport, 1.4 inches in Springtown (Bucks County), 1.0 inch in Palm (Montgomery County) and Bechtelsville (Berks County), 0.7 inches in Furlong (Bucks County) and 0.5 inches in Glenmoore (Chester County). A cold front slowly moved through Eastern Pennsylvania during the night of the 5th before stalling in the Delmarva Peninsula during the morning of the 6th. A weak low pressure system developed along the frontal boundary and was in West Virginia during the morning of the 6th. As the low pressure system moved southeast of the region during the afternoon and evening of the 6th, it pulled the cold front farther south and ended the precipitation. The other player was a high pressure system which built east from the upper Mississippi Valley the morning of the 5th into Ontario Province the morning of the 6th. This high pressure system supplied fresh cold air and helped change precipitation from liquid to frozen across the region.