Interactive mesoscale objective analysis in the National Weather Service’s Graphical Forecast Editor

The Graphical Forecast Editor (GFE, Forecast Systems Laboratory, 2001) is being utilized at the Weather Forecast Office in Tulsa, Oklahoma not only to generate forecast products, but also as an interactive mesoscale objective analysis tool. The latter use involves the generation of environmental parameters associated with severe local storm forecasting, such as lifted index, helicity, and shear. Locally developed scripts, referred to as SmartTools, allow for calculations to be performed at resolutions higher than previously available to field forecasters. In addition, variations on classic parameters can be displayed, such as storm-relative helicity (SRH) computed to the lifting condensation level (LCL) instead of to an arbitrary height. The forecast parameters are produced by a combination of editable surface data and forecast fields from numerical models. Thus a forecaster can produce either an analysis of the current hour (as is done by other schemes that mix observed surface data with model data from higher levels), or produce forecast fields, adjusting for biases in model surface data. Early work with this analysis technique has been perceived as beneficial by forecasters when making Hazardous Weather Outlooks and issuing National Weather Service warning products. Examples of the available output and associated forecaster interaction will be shown, along with a case event that illustrates the potential benefits of these data in anticipating storm evolution.

* Corresponding author address: Steven Piltz, National Weather Service Forecast Office, 10159 East 11th Street, Suite 300, Tulsa, OK 74128; email steven.piltz@nooa.gov