Cool days bound to pass; Vegas heat set to return

Ed Koch and Will Oremus

Thursday, June 26, 2003 | 10:59 a.m.

Mark Twain once said, "the coldest winter I ever spent was a summer in San Francisco."

If that's the case, would Twain have needed to bundle up in Las Vegas on Wednesday?

It wasn't really that cold, however an unusual weather phenomenon in the West caused the official temperature for usually chilly San Francisco to be one degree hotter than normally sweltering Las Vegas.

The official temperature for San Francisco at its airport was 93 degrees, though the unofficial downtown temperature was 89 degrees, the National Weather Service said. The official Las Vegas high temperature measured at McCarran International Airport was 92 degrees, the weather service said.

"It has happened before, but not often -- conditions have to be just right," said Brian Fuis, spokesman for the National Weather Service in Las Vegas.

"In San Francisco they had an offshore flow -- winds blowing from land to sea, similar to how the Santa Ana winds make it hot in Los Angeles. In Las Vegas we had a northwest flow that brought a cold front in, which now is gone."

Similar conditions on Tuesday resulted in a new "coolest high" record being set in Las Vegas, when the daytime temperature reached only an 86-degree peak. It broke the previous low high mark of 87 set in 1963, Fuis said.

Samantha Mohr, weather forecaster for KPIX Channel 5, the CBS affiliate in San Francisco, said: "It's unusual. We actually tied a record for the day (that was set in) 1976. It is unusual to get that hot in San Francisco proper, though on the peninsula it will often be a lot warmer.

"When we have an offshore flow and the air comes off the desert or the central valley, everybody gets hot. Normally our sea breeze keeps us cool. An offshore flow pushes the fog well off the coast."

KLAS Weather Manager Kevin Janison said: "When we have the abnormal conditions like we had today, it makes me worry that we've lost our orbit and are racing to the sun. I would load up with as many canned goods as possible.

"We had cool air come down from the north, and that cool air was replaced by warmer air. They were up in the 90s even in Oregon today. They're not going to hold on to that for too much longer, they're going to ship it back down here."

But don't expect San Francisco to be hotter than Las Vegas again anytime soon.

Today's high in Las Vegas is expected to be 99 degrees, followed by 104 on Friday and 105 Saturday, Fuis said noting that a large, strong high pressure area has settled over us.

Janison agrees: "Life is going to return to normal."