Winter Weather in Pennsylvania, March 14, 1997

A low pressure system that developed over the southern Rockies the afternoon of the 12th and a high pressure system over nearby Canada that kept a wedge of cold air in place over Eastern Pennsylvania helped produce a wintry mix of precipitation across the area on the 14th. The low pressure system was in Ohio the morning of the 14th. A second low formed along its associated warm front over the Delmarva Peninsula during the day on the 14th and slowed the progression of warmer air into northern Pennsylvania. By the morning of the 15th, the secondary low was over the Atlantic to the southeast of Cape Cod. Precipitation started as snow across the area prior to dawn on the 14th. It changed quickly to freezing rain and sleet in the northwest Philadelphia suburbs and the Lehigh Valley by dawn. Accumulations were less than an inch. The change to sleet and freezing rain took longer over the Poconos where accumulations averaged two to three inches prior to the change over. Warmer air slowly moved northwest and eventually scoured enough of the cold air to end the freezing rain across the northwest Philadelphia Suburbs and Berks County by 9 a.m. EST, the Lehigh Valley by 11 a.m. EST and the Poconos by 3 p.m. EST. Untreated roadways were treacherous. Indirect insolation from the March sun and temperatures near the freezing mark prevented significant accumulations of ice prior to the change to plain rain.