1. Holly A. Anderson Spring 2007 – Synoptic II Florida State University Introduction On December 10, 1995, Buffalo, New York experienced a record-breaking 37.9 inches of snow within a 24-hour period. A combination of frigid artic air and a long fetch of southwesterly winds over Lake Erie created the single narrow band of intense snow that remained over the area for an extended period of time due to the veering and backing of low-level winds. This study explores the synoptic situation and mesoscale processes which led to the creation and propagation of the convective lake-effect snow band that produced this record-breaking snowfall. The data used in this study is NCEP Reanalysis Data with 6 hour intervals. Conclusion As a 500 mb upper-level trough moved to the northeast over Great Lakes area on December 10, southwesterly flow allowed cold artic air to pass over Lake Erie. The cold air was destabilized, allowing a narrow snow band to form. This lake-effect band of snow deposited record-breaking snowfall amounts over the metropolitan Buffalo area as it continued to remain rather stationary over the area due to low and upper level flow patterns. The synoptic and mesoscale situation over Lake Erie and Western New York created the perfect situation for a lake-effect snow storm to form and reside over the metropolitan Buffalo area long enough to create record-breaking snowfall amounts. References The Use of High Resolution Hourly Forecast Soundings for the Prediction of Lake Effect Snow, Thomas A. Niziol and Edward A. Mahoney, NWS, Buffalo, NY A RECORD-BREAKING LAKE EFFECT SNOWSTORM IN BUFFALO, NEW YORK ON 10 DEC 1995: A CASE STUDY, Joby Hilliker, The Pennsylvania State University, 1996 NCEP North American Regional Reanalysis Atmospheric Soundings, University of Wyoming Irv Watson, NWS, Tallahassee, FL This image shows Total Snowfall Amounts for December 9-11, 1995. Because the band of snow was so narrow, Buffalo, NY received record-breaking amounts of snow while locations just miles north or south received far less. The MSLP and 500 mb plot (left) and the associated wind plot (right) show a low pressure system centered just north of the Great Lakes. As a 500 mb trough lifts to the northeast, a cold front associated with the system passes through New York. Low-level winds in the area begin to back towards the west-southwest. This Base Reflectivity radar image from Buffalo, NY at 1418Z on December 10 shows the single band of lake-effect snow oriented SW/NE over Lake Erie. 12Z December 10 1995 As the low deepens and the 500 mb trough continues to lift towards the northeast, cyclonic vorticity brings in cold artic air and lower thicknesses. Wind barbs in the Great Lakes region indicate that the fetch is maximized over the relatively warm Lake Erie as the wind is southwesterly. This creates the perfect scenario for the cold air to be moistened and destabilized, creating convective bands of lake-effect snow. Wind direction encourages the bands to consolidate into one narrow, elongated band oriented SW/NE. 00Z December 10 1995 00Z December 11 1995 The 500 mb trough is now centered southeast of the Hudson Bay. Because surface winds have veered to the west and northwest and therefore no longer blow parallel to the snow band’s axis, the single snow band breaks up into multiple bands and is pushed southwest of the Buffalo area.