Many discussions about the utility of the North Alabama Lightning Mapping Array (NALMA) focus on the utility of the observations in providing additional lead times for severe weather warnings. However, the past week has highlighted several cases where the NALMA data have been beneficial to forecasters in a non-severe environment as SPoRT conducts an intensive evaluation of the network this month and into June.
All of SPoRT’s partner NWS offices using NALMA data have expressed the utility of the data with “pulse” type thunderstorms that form and dissipate quickly and sometimes result in brief severe weather. The NALMA has been used for situational awareness to see which storms observed on radar may require additional attention.
This was used on Memorial Day weekend by forecasters from the Huntsville office. At 2:40 pm a storm was moving northward towards the city of Decatur, Alabama where the Alabama Jubilee was being held. As the forecasters said,
“Radar showed that the storm was clearly building, but we were able to provide additional lightning information to the [Morgan County] EMA with about 20-25 minutes of lead time.”
This additional information ensured that everyone had a safe holiday when the storm moved over Decatur around 3:05 pm.
The following day, the Morristown, Tennessee NWS office used the NALMA data to update their Terminal Aerodrome Forecast (TAF) for the Chattanooga airport. In the survey submitted by the Morristown Science and Operations Officer,
“I utilized the NALMA to help in the TAF decision making process. The national [cloud-to-ground] lightning data did not have any lightning strikes with a line of convection moving north out of Georgia. However, the NALMA did pick up on the growing number of [intra-cloud] flashes, which gave me a heads up to include thunder in the TAF. Lighting was reported at the Chattanooga TAF site during the next couple of hours.”
Both of these are small, localized cases, but hightlight the potential of the NALMA observations to help provide lightning safety to the public and aviation interests.