Impressive squall line moving across the Tennessee and Ohio Valleys this afternoon producing lots of severe weather reports. High resolution WRF simulations (shown below) indicate this system may the cross the Appalachian Mountains around midnight. Timing of this system will be problematic and simulations are already slower then radar observations indicate. In very general terms, the NMM appears to be slightly faster and maintains the system more, at least into the very early morning hourse. Local experience has shown that the reflectivity products from the NMM runs are often times stronger then those forecast by the ARW. It will be interesting to see how well this system maintains intself overnight.
This event relates to a recent paper in Weather and Forecasting from a recent CSTAR project.
Forecasting the Maintenance of Mesoscale Convective Systems Crossing the Appalachian Mountains
Casey E. Letkewicz, Matthew D. Parker