Nowcasting with the Local Analysis and Prediction System (LAPS)

LAPS is a highly portable, computationally efficient Numerical Weather Prediction (NWP) data assimilation and forecast system. It holds high fidelity to observations and high speed due to the multiscale methodology used in the newest variational version of LAPS (vLAPS). It produces frequently updated (15 minute), fine scale (1 km) analyses using most locally available observations, and ensuing forecast products (generated using vLAPS initialized Weather Research Forecast (WRF) model) with low latency. With these qualities, vLAPS is well positioned for application in situational awareness and very short term forecast (nowcasting).

The Experimental Warning Program (EWP) of NOAA's Hazardous Weather Testbed (HWT) is held at the National Weather Center every spring since 2008. EWP provides a platform to evaluate vLAPS monitoring and nowcasting skills. In this presentation, we will describe the variational version of the Local Analysis and Prediction System (vLAPS). We will select several cases of supercell storms and tornadoes from both EWP 2013 and 2014 to highlight the real-time performance of variational LAPS including some feedback from forecasters, issues identified, and discuss plans for future improvement.