The extension of lightning flashes from thunderstorms near Cape Canaveral, Florida

Abstract

The horizontal distance that intracloud (IC) and cloud to ground (CG) lightning flashes extend from thunderstorms is presented for warm season nonsevere storms near Cape Canaveral, FL. The Warning Decision Support System-Integrated Information (WDSS-II) software allowed us to ingest, display, and make distance calculations using radar reflectivity data from nearby National Weather Service Offices and lightning information from the National Lightning Detection Network and the local Lightning Detection and Ranging network. The flash distances were determined manually using a measuring tool within WDSS-II. Six categories of flashes were investigated: (a) CG flashes measured from the edge of the convective core (30 dBZ) to the ground strike location that is beneath the attached anvil, (b) CG "bolt from the blue" flashes measured from cloud edge (0 dBZ) to the ground strike point that contains only 0 dBZ overhead, (c) CG bolt from the blue flashes as in Category B but measured from the edge of the precipitation (18 dBZ), (d) IC flashes that exit a portion of the cloud that is not an anvil, measured from cloud edge (0 dBZ), (e) IC flashes within anvils measured from the edge of convective precipitation (30 dBZ) to the termination point within the anvil, and (f) IC flashes exiting the edge (0 dBZ) of anvils. Results for each category are presented in the forms of frequency distributions of distances and their cumulative frequency distributions.

Diurnal characteristics of lightning flashes detected over the São Paulo lightning mapping array

“…As a result, it would be reasonable to assume that the storms occurring during this diurnal segment, given the weakening of vertical turbulent mixing and greater influence of midlevel winds, distribute the cloud charge in a more stratified manner, resulting in flashes of larger horizontal/vertical spans. Examples of these would be the observed large horizontal IC flashes termed “anvil crawlers” [ Fuelberg et al , ] or CG lightning flashes in mesoscale stratiform precipitation [ Lang et al , ]. This cycle is disrupted around sunrise, when the surface heating gradually rebuilds the vertical moisture transport and invigorates vertical mixing.…”

Characteristics of a multi-stroke “bolt from the blue” lightning-type that caused a fatal disaster

“…The radar station is about 70 km away from the location of the lightning accident, and it completes the body scanning process every 6 min. Fuelberg et al (2014) measured the horizontal development distance of different types of lightning channels that extend from a thunderstorm cloud; three are used for the ground flash process, and three are used for the cloud flash process. There are two ways to measure the horizontal development distance of a lightning channel: the horizontal distance from the edge of the anvil to the lightning strike point (0 dBz) or from the edge of the precipitation area (18 dBz) to the lightning strike point.…”

Using radar‐derived parameters to forecast lightning cessation for nonisolated storms

“…Our definition of nonisolated was highly restrictive. There are many other scenarios by which lightning can extend between clouds, and flashes can travel long distances from their parent cloud [Fuelberg et al, 2014]. We also did not consider lightning extensions within the same cell (Figure 1), flashes within or extending from an anvil [e.g., Dye and Willett, 2007;Kuhlman et al, 2009], or bolts from the blue [Rison et al, 2003].…”

“…Another difficulty in forecasting lightning cessation is that flashes can extend far from both the convective core and cloud edge. Fuelberg et al [2014] documented IC flashes within anvils over Florida that extended greater than 50 km away from the storm's 30 dBZ core. They also measured the horizontal straight-line distance from the edge of the cloud (0 dBZ) to overhead the CG strike location.…”

“…Since there was no reflectivity over the strike location, it was considered a "bolt from the blue" [Rison et al, 2003]. Fuelberg et al [2014] found that most bolts from the blue in Florida extend less than 4 km from cloud edge, and none extended farther than 9 km. However, bolts from the blue have been observed to extend more than 25 mi (15 km) from cloud edge (NOAA, http://www.lightningsafety.noaa.gov/bolt_blue.htm).…”