Cloud cover and gusty winds rolled into the Las Vegas valley on Tuesday evening as a band of monsoon moisture moved in, bringing the first real shot at showers and thunderstorms overnight and into Wednesday morning. Desert Doppler picked up slight organization of showers and thunderstorms south of 1-15 at 5:30pm, a sign the system was beginning to take shape near the region.
The wettest window was expected between 12am and 5am, when the Las Vegas metro area had only a slight chance of showers, before the rain chance in the valley rose to 40% between 6am and 12pm Wednesday. A stray thunderstorm could also develop, bringing dry lightning and gusty winds, while the overnight low was forecast at 86° and Wednesday's high at 105°.
That is what makes the forecast relevant today: the change is arriving during a hot stretch, with temperatures still well above 100° and gusts already running 10-20mph before strengthening toward 30mph through Wednesday, Thursday and Friday. Much of the precipitation that does form may never reach the ground, because warm, dry air near the surface can strip out the moisture before it falls far enough.
By Wednesday afternoon, the system was expected to push east and rain chances were set to fall, even as stray thunderstorms could linger in the morning. The forecast then turns back to heat, with Thursday's high at 106° before temperatures ease back into the 90s on Saturday and Sunday. For people in the Las Vegas valley, Boulder City, Henderson and Laughlin, the question is less whether moisture is nearby than how much of it survives long enough to amount to measurable rain.
The broader pattern points to a short-lived burst of monsoon weather rather than a lasting cool-down. Southern Nevada is getting its first dose of moisture, and while the airport may be trying to break a 100+ dry streak, the atmosphere still looks too hot and dry to make every shower count.
