Research

This project has three Co-Investigators, Drs. Ahlquist, Cooper, and Fuelberg. Each investigator has a separate and distinct set of research tasks. Dr. Fuelberg's research component is described below.

We are developing climatologies of cloud-to-ground lightning for a number of County Warning Areas (CWAs) within the NWS Southern Region. These CWAs are coastal regions where the sea breeze is the dominant forcing mechanism for warm season convection and mountainous areas where topographic forcing is important. Separate climatologies will be developed for each major large-scale flow regime that occurs at each selected CWA. Climatologies also will be prepared as a function of time of day. We hypothesize that lightning will not be uniformly distributed over these various CWAs, but that local maxima and minima will be found due to the local forcing mechanisms.

These lightning climatologies will help local forecasters better predict the onset, spatial coverage, and duration of precipitation that occurs under weak synoptic forcing. The results can be incorporated into the local IFPS/GFE system as done in Tallahassee and Tampa (Watson et al., 2003). With this new high resolution local information, forecast products should better attain the levels of time and space resolution that are consistent with the goal of a "No Surprise Weather Service".

Our methodologies are based on the procedures of Watson and Holle (1996) that are described fully in Camp et al. (1998) and illustrated in Lericos et al. (2002). Briefly stated, approximately fourteeen years of warm season NLDN data will be counted (bined) within 5 x 5 km boxes that encompass each CWA. These counts will be displayed in color to clearly reveal the lightning patterns. Geographical data (roads, rivers, topography, etc.) will be superimposed onto the lightning patterns to facilitate their interpretation. Unlike our past efforts, the current research is making extensive use of GIS capabilities.

Several different types of lightning products will be constructed (Fig. 2). The first will examine the composite of all days and hours regardless of wind direction and time of day. Results will indicate overall areas of enhanced or diminished storm activity. Once these patterns are understood, a second class of computations will examine lightning patterns as a function of low-level wind direction. A third class of computations will examine the diurnal aspects of lightning. Finally, we will stratify the data according to thermodynamic conditions deduced from radiosondes, e.g., precipitable water, stability, etc.


Fig. 2. Composite of all days and hours independent of wind direction.

As a final effort, Geoff Wagner is using the lightning climatologies, together with gridded forecasts of winds and thermodynamic parameters, to develop a statistical product that will forecast areas where lightning will be initiated. This product can be used by the local NWS forecast offices.

We are working closely with the SOOs at the local offices whose conditions we are investigating. These NWS collaborations include Deirdre Kann (ABQ), Richard Wynne (AMA), and Steven Cobb (LBB). They are heavily involved in determining the ways in which the lightning data should be stratified, i.e., by wind direction or other criteria. The research is being performed iteratively, i.e., tentative results from each phase will be sent from FSU to the NWS offices for their interpretation and suggestions before proceeding to the next phase of calculations.