87th AMS Annual Meeting

Saturday, 13 January 2007
New York State Finger Lakes Winter lake-effect events: Surface, sounding, and synoptic environment
Ryan Sobash, University of Oklahoma, Norman, OK; and N. Hodas and N. Laird
Much of the current knowledge regarding lake-effect snow storms is associated with large water bodies, such as the Great Lakes and the Great Salt Lake. Snowfall events attributed to small lakes (fetch < 100 km) have received less attention, although significant snowfall totals have been documented with these systems. This study uses data from the eleven winters (October March) of 1995 through 2005 to examine the characteristics of lake-effect systems in the Finger Lake region of New York State (NYS). WSR-88D radar data from Binghamton, NY was used to identify 108 lake-effect events which contained quasi-stationary precipitation bands aligned with a major-axis of one or more of the Finger Lakes. The lake-effect events were classified into three main categories: Finger Lakes (36), Lake Ontario-enhanced (57), and synoptic-enhanced (15). In addition, 17 cases occurred which transitioned from one main category to another during the lake-effect systems evolution.

Hourly surface data and soundings were used to investigate atmospheric conditions during lake-effect events. Surface temperatures and wind speeds were found to be lower during Finger Lakes lake-effect events than either Lake-Ontario enhanced or synoptic enhanced events. Wind directions were most commonly from the northwest; however mesoscale variability in wind direction was observed at surface station throughout the western NYS region. Analyses of soundings which occurred during events found that the mean base of a lower-tropospheric stable layer was significantly lower during Finger Lake events (880 hPa). Examination of the synoptic environment favorable for lake-effect events within the NYS Finger Lakes region showed a systematic shift in the surface temperature and sea-level pressure patterns between synoptic-enhanced, Lake Ontario-enhanced, and Finger Lakes events.

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