Unger, Scott W; Laws, Kevin B; Goggins, Gary D; Talley, Jessica ; Case, Jonathan

Tara N. Golden and Holly M. Britton
National Weather Service Forecast Office Birmingham, Alabama

For the last three years forecasters at the NWS Weather Forecast Office in Birmingham, Alabama have been producing daily morning analyses of mesoscale boundaries using detailed, real-time analyses of surface observations, NEXRAD data, Geostationary Operational Environmental Satellite imagery, and Land Information System data generated at the NASA Short-Term Prediction Research and Transition Center. Such boundaries include old thunderstorm outflow boundaries, horizontal convective rolls, differential heating boundaries, shallow prefrontal troughs, and deep synoptic fronts. Output from the Land Information System included high-resolution depictions of soil moisture, latent and sensible heat fluxes, skin temperature, and evapotranspiration as a result of a cycled integration of the Noah land surface model driven by NCEP model and precipitation analyses, and short-term forecasts. The results of these analyses demonstrate that convection is either directly initiated or organized through these features; thereby dispelling the myth of random, pop-up summertime thunderstorm activity.

In the first year the focus was simply recognizing where preferred origination zones of summer convection would be each afternoon. In the second year subjective short-term forecast polygons were added to the analyses to highlight the regions favoring afternoon convective initiation across the forecast area. The project culminated in the third year with an objective look at how the short-term polygons compared to operational forecasts. This presentation will describe the daily procedure used to identify the boundaries, including the short-term forecast polygons, and the results of what meaningful forecasts of summertime convection can bring operationally to central Alabama and surrounding regions.