Multiple Severe Weather Events in the Las Vegas Valley and Impact-Based Decision Support Services provided by NWS Las Vegas, NV during the Monsoon of 2018

Severe convective outflow winds and microbursts impacted the Las Vegas Valley on consecutive evenings, producing damage in excess of 1.5 million dollars. On the evening of 19 July 2018, severe convective outflow winds (25-30 m s^-1) pushed southwestward and into the Las Vegas Valley from convection that initiated earlier in the day over the higher terrain of southwest Utah. Winds were enhanced as they passed through the Frenchman Mountains and initiated additional convection along the leading edge of the outflow. The resultant convection triggered a damaging microburst along the eastern side of the Las Vegas Valley, snapping 19 power poles. The following day, 20 July 2018, isolated convection grew atop the McCullough Mountain Range in far southern Clark County, Nevada. The convection moved to the north and into the Las Vegas Valley, resulting in a series of intensifying microbursts that impacted the southern portions of the Las Vegas Valley. The strongest of these microbursts produced severe wind gusts in excess of 35 m s^-1. This presentation will detail the impact-based decision support services provided by NWS Las Vegas prior to and during these events. An emphasis will be placed on the continual communication that occurred with emergency management personnel during the late afternoon/evening of 20 July 2018 when crews were deployed. Ultimately, this event catalyzed the development of a local text messaging program designed to increase the IDSS efficiency with core partners when impactful weather conditions arise.