A group of tourists use umbrellas to shield themselves from the sun while walking down the Strip,Tuesday, Aug. 21, 2012. ( Christopher DeVargas )
Chance of thunderstorms this week triggers flash flood watch
By Dave Toplikar, Las Vegas Sun and U.S. News Agency / Asian
We all suffered though it this month: warm, sticky asphalt on our shoes; flesh-burning, oven-like car interiors and the sauna-like outdoor conditions that make you flee to the sanctuary of air conditioning.
But those who keep tabs on the weather say this isn’t unusual — it’s just a typical hot August in Las Vegas.
In fact, a local National Weather Service meteorologist said the early part of the summer was actually relatively cool for the desert-spawned city.
“We have had a couple of weeks where it was really hot. But on average, it hasn’t really been that extreme,” Andrew Gorelow said Tuesday as he sifted through local climate data from the National Weather Service.
Going through the data, Gorelow found August has been warm — the average temperature so far has been 3.3 degrees above normal. That’s mostly from a streak of hot days that ran from Aug. 7-13 when the high temperatures were at least 108 degrees and peaked as high as 112.
However, temperatures took a dive to more normal highs starting Aug. 16. At that time, heavy clouds began rolling in from the south as part of the normal monsoon pattern, this month’s climate data show.
“When it comes down to it, August tends to be our more humid month, when the monsoon is really kicking in,” Gorelow said.
“And that’s why we’ve just been feeling a little more moist,” he said. “We usually do have a higher moisture content in August than we usually do in July.”
Monsoonal moisture from Mexico brought more scattered thunderstorms around the region Tuesday afternoon, with some of the storms expected to drop heavy rains and small hail, he said.
Also, a trough of low pressure coming off the California coast will increase the thunderheads moving through, bringing the possibility of more storms across the Las Vegas Valley on Wednesday and Thursday, he said.
The weather service has issued a flash flood watch for the valley from 11 a.m. Wednesday until 1 a.m Thursday, with rainfall amounts up to 2 inches.
But on Friday, the valley will start drying out, Gorelow said.
Because of more moisture and more clouds, afternoon temperatures will be cooler, reaching only the upper 90s.
Overall, while it might seem hotter, this summer won’t be anything of note for heat records, Gorelow said.
“It could be the perception that because the rest of the country was so hot, we must be that hot,” he said. “But in reality — in July at least — we were below normal for the month.”
Gorelow said there was one week, from July 7-11, when the afternoon high temperatures reached 107, 110, 113 and 114 degrees.
However, for the entire month, July was 1.6 degrees below normal for its average temperature, Gorelow said.
He also looked at average temperatures from June 1 to Aug. 20 to see how this year compared to the past few years.
This year’s average for that 81-day time period was 91.4 degrees. That period in 2011 had an average of 89.6 degrees, and the average was 92 degrees in 2010.
He also looked at peak afternoon temperatures from June 1 to Aug. 20 for the past few years. He said 2010 was 103.2 degrees, 2011 was 101.2 degrees and this year was 102.8 degrees.
“So 2010 was definitely warmer than the last two years,” he said.
The extended forecast for the rest of August indicates the high heat is gone for the summer, he said. The models show peak afternoon temperatures will be in the low 100s through Aug. 28, he said.
On average, high temperatures in Las Vegas fall to 99 degrees on Aug. 31. High temperatures fall into the 80s by Sept. 27, he said.
Gorelow said it’s difficult to make any conclusions with the data.
“July was a little below normal. August was a little above normal. But in reality, I think it’s been a pretty much normal summer for temperatures,” he said.