680 A Climatological Analysis of Snowband Predictability in Northeast Winter Storms Including Case Studies

Tuesday, 14 January 2020
Hall B (Boston Convention and Exhibition Center)
Mark Nissenbaum, Florida State Univ., Tallahassee, FL; and R. E. Hart

For several decades now it has been observed that within the broader precipitation field of winter cyclones there are often mesoscale areas of intense precipitation that can lead to poorly forecast areas of heavy snow. At the same time, our understanding of the causes of the bands has improved – including mechanisms such as conditional symmetric instability and frontogenesis among them. However, until about 15-20 years ago, numerical models did not have the horizontal or vertical resolution to accurately resolve these very fine-scale processes explicitly. While numerical prediction models continue to improve and achieve finer resolution, it remains unclear how well the models resolve these processes today. This poster will examine the predictability of mesoscale snow bands in noteworthy winter storms using the NCEP GFS and NAM models as compared against the GridRad dataset. Effort is made to understand why some forecasts are successful and why others perform poorly. Emphasis is placed on examining the causes of mesoscale snow bands and when the earliest suspicion of band development occurs. The analysis is made possible by proposing methods to objectively quantify the existence and location of the mesoscale snow bands from both model output and radar.
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