On 2-3 January 1999, a blizzard passed to the southeast of Lake Michigan. Lake effect snow bands were observed prior to the arrival of the main precipitation shield and numerous snowbands were detected throughout the event, with total snowfall varying from 25-60 cm throughout the region.
Once daily forecasts from a quasi-operational version of the Pennsylvania State University – National Center for Atmospheric Research (PSU-NCAR) fifth-generation Mesoscale Model (MM5) with interior nesting to 5 km grid spacing are used to examine the predictability of the snowbands in this event. Subjective comparisons of model performance are combined with quantitative measures of synoptic scale forecasts of pressure, wind and temperature for 00-24h and 24-48h ranges. These comparisons indicate reliable synoptic-scale forecasts of the cyclone event at both time ranges. A comprehensive comparison of model output with high-resolution, WSR-88D derived precipitation data, ground-truthed using all available gage data, shows useful QPF skill for this event.
Using the baseline model forecast as a control, additional model runs were conducted to assess the direct impact of the lakes on the precipitation bands in this event. This assessment includes not only precipitation, but the mesoscale structures of pressure, temperature, and wind and the associated dynamics. The connection between synoptic-scale structure and the in-situ mesoscale forcing provided by the lakes is addressed with respect to the general problem of mesoscale predictability.