Keep your eye on the sky over the next couple of days, as the Las Vegas Valley has a chance this weekend to break its record 200 days-and-counting streak without measurable rain.
But also beware of the roads, as the storm will likely deliver only enough to make the blacktop slick.
Two weather systems with the potential for precipitation are moving into the area this weekend — a windy one blowing through today and a heavier, wetter one on Sunday, said Dan Berc, a meteorologist at the National Weather Service’s Las Vegas station.
He said there’s a 50-50 chance the latter system will bring measurable rain to McCarran International Airport, where the weather service takes its official measurements. Berc predicted no more than a tenth of an inch, but a tenth of an inch is “measurable,” and if at least that much falls, it would break a dry streak that started on April 20.
On the downside, that rain could mix with six months’ worth of accumulated oil on the roads, making for slippery driving even with a small amount of water, Berc said.
“It's not like ice and snow where we can slow down for it,” he said. “We don't see it.”
UNLV climatologist Matt Lachneit said a dud of a monsoon season this summer drove the current situation, and failed monsoons aren’t uncommon in Vegas. Extended high-pressure systems blocked much of this year’s seasonal moisture from coming up the Colorado River corridor, he said, though it wasn't clear what caused that blockage in the first place.
That the lack of rain has extended this long, even into the typical start of the winter storm season, is less usual, though still not necessarily outside the norm, he added.
“It is unusual, but I'm not overly surprised at least yet,” Lachneit said. “If this happened for multiple years in a row, that's when I would really start to think that we're pushing far beyond the limits of normal.”
Make no mistake, though: It’s crispy out here. According to the National Drought Mitigation Center at the University of Nebraska, all of Nevada is in some level of drought. More than half the state, including the Las Vegas metro, is in “extreme” drought. At the start of the year, only 2% of the state was even considered “abnormally dry.”
The lack of rainfall over Nevada doesn't have immediate effects on the region’s drinking and agricultural water needs, Lachneit said, as much of that water is imported from the Colorado out of state.
But parched landscapes in the Spring Mountains, for example, leave the area vulnerable to wildfire, he said. And a La Niña event brewing in the Pacific Ocean portends more dry months ahead.
Vegas’ current dry spell shatters a record set in 1959, when the area went without rain for 150 days.
While this weekend might not be too soggy in the valley, Berc said he was more confident of precipitation on Mount Charleston, especially on Sunday: three to six inches of snow above 7,000 feet and one to three inches at lower elevations, with a snow level of around 4,000-4,500 feet.
However much rain or snow the region gets, the storm will be short-lived and gone by Monday, Berc said.
After that, there’s no more moisture forecast for the near future.