Visualizing the Seasonal Shift of IPF Precipitation in the SE United States

Visualizing the Seasonal Shift of IPF Precipitation in the SE United States

By Mary Brown, Dr. Rosana Nieto Ferreira

Abstract

Isolated precipitation features (IPF) are short-lived, small, and spatially heterogeneous features that are most predominant during summertime in the southeast United States. They are thermodynamically driven and make up 30%-50% of the total summer precipitation. Using radar data and a precipitation organization classification algorithm, Rickenbach et al. (2015) established that the springtime transition to predominantly IPF occurs abruptly between the months of March-June. The goal of this study is to investigate whether the Weather Research and Forecasting model (WRF) is able to capture the observed springtime transition to increased IPF and shed light on the mechanisms for the shift. To that end WRF simulations for mid-May to mid-June 2009 will be run using a set-up similar to that in Lackmann (2013). Two resolutions will be tested for use with the precipitation organization classification algorithm, that is a 3 km and a 6 km innermost nested grid. The results of this study will later be extended to a study of the effect of climate change on the abrupt onset of the IPF rainy season in the Southeast United States.

References:

Lackmann, G.M., 2013: The south-central U.S. flood of May 2010: Present and future. Journal of Climate, 26(13), pp.4688–4709.

Rickenbach, T. M., R. Nieto-Ferreira, C. Zarzar, and B. Nelson, 2015: A seasonal and diurnal climatology of precipitation organization in the southeastern United States. Q. J. Roy. Met. Soc., 141, 1938-1956.