The third and final observation season of UPLIGHTS took place from 30 May 2014 – 31 Aug 2014. There were a total of 94 operations days with assets deploying on 27 days (29%). High-speed camera captures were made on 21 days (22%). There were 42 down days (45%) in which weather conditions precluded any chance of observations.
During the 21 days when high-speed captures were made, there were a total of 289 flashes observed encompassing 515 individual high-speed captures. A breakdown of captured flash types is given in Table 1 below.
There were 17 upward flashes observed during the operations timeframe. The 6 storms associated with the 17 upward flashes occurred on 4 different days all in the month of June: 1, 14, 21, 28. One of the upward flashes on 14 June was an upward negative leader from Tower 1. This is the first and only upward negative leader observed from 2004 – 2014.
One of the upward flashes on the evening of June 21 involved a 109 m tall cell tower along Highway 16, 3 km north of Keystone SD. It was observed by the assets observing the towers in Rapid City. On the night of 27 June, the truck drove to Presho SD and captured two upward flashes from a 332 m tall television tower.
Table 1. Flashes captured with high-speed cameras
UP | +CG | -CG | IC | Total |
17 | 142 | 107 | 40 | 289* |
UP = upward flash
+CG = positive cloud-to-ground flash
-CG = negative cloud-to-ground flash
IC = cloud flash
*The total reflects the sum of CG and IC flashes. The 17 upward flashes occurred during either a CG or IC flash.
17 total upward flashes from 2014 by UT date:
1 Jun: 2 (17:36:11 – 117:37:21), 5 (22:46:30 – 23:17:42)
15 Jun: 4 (02:00:01 – 02:27:38)
22 Jun: 3 (02:20:20 – 02:28:29)
28 Jun: 2 near Presho SD (05:43:59 – 05:49:53), 1 (23:47:15)