March is the beginning of meteorological spring in the Northern Hemisphere. Frequent spring storms in the United States combined with improvements to Vaisala’s NLDN and GLD360 networks resulted in very large counts of lightning during March 2016. This was true in both the United States and around the globe.
Storms occur in the southeast half of the United States every spring, but this year the March lightning activity was more similar to mid to late April (comparing to past years). The NLDN underwent a substantial upgrade in cloud pulse detection through the summer of 2013, and more than twice as many cloud pulses are now detected since the upgrade than before the summer of 2013.
A particularly intense period of lightning occurrence began on 8 March and lasted several days. A nearly stationary frontal boundary from Texas to the northeast resulted in strong low-level flow from the south bringing copious amounts of moisture northward. There were hundreds of thousands of strokes and rain up to 15 inches in Louisiana and Arkansas during this period. Several additional but less intense multi-day scenarios were established later in the month across the southeast United States that produced very large lightning frequencies.
Globally, the GLD30 network doubled the number of detections beginning on 18 August 2015. This major change in network performance took place somewhat after the summer lightning maximum in the Northern Hemisphere activity. The increased detection is becoming especially apparent as Northern Hemisphere lightning increases again, and such record counts compared with the same months last year can be expected to continue through 2016.
Since both the NLDN and GLD360 network have been substantially upgraded, the global and United States lightning frequencies reached levels for the month of March not seen in the past as spring storms erupted over the southeast United States.