May 21 - July 31
Sensitivity of Planetary Boundary Layer Parameterization Schemes on Forecasting Blizzard Conditions for the 11–12 December 2010 Snowstorm
Nathan Korfe, Heather Reeves, and Adam Clark
What is already known:
- Winter snowstorms associated with large amounts of blowing snow are hazardous for public safety.
- Surface winds must be accurately forecasted to predict the visibility.
- Changing the PBL parameterization scheme in numerical models may improve the surface wind forecast for blizzard conditions.
What this study adds:
- Demonstrates how different PBL schemes can have significant effects on a surface wind speed forecast for a winter storm that occurred on 11 December 2010.
- Model visibility was not a good predictor of short-term visibility for that case. Provides basis for further investigation into PBL sensitivity with severe winter storms.
Abstract:
Producing blowing snow and visibility forecasts for severe winter storms poses a significant challenge to numerical models. Changing the planetary boundary layer (PBL) parameterization schemes in numerical weather models may improve the forecast for blizzard conditions, but it is uncertain how much the forecast is dependent on different PBL parameterization schemes. The study examines five experiments, each with a different PBL scheme, using the Weather Research and Forecasting (WRF) model for a winter storm that occurred 11-12 Dec 2010 in the upper Midwest. Of the five experiments, the MYJ does not produce any blizzard conditions, while the MYNN and ACM2 provide the most accurate forecast of blizzard conditions with a significant area of surface winds 15-17 m s-1 in western Iowa. Liquid precipitation and model visibility are also considered. Although very similar over areas with widespread blizzard conditions, MYJ and QNSE produce accurate maximum precipitation forecasts with 55 mm. The model visibility does not show any significant changes from scheme to scheme.