Northwest dry while Southwest gets heavy rain
Thursday , September 13, 2012 - 7:11 AM
SEATTLE— Heavy rains and flooding in the Southwest? A near-record dry streak in Seattle?
The seemingly counterintuitive weather is not necessarily unusual for this time of year, but it’s striking when compared with the usual opinions about the regions — overcast and rainy in the Northwest and sunny skies in the Southwest. But late summer is typically the sunniest, driest part of the year in Washington and Oregon, while the Southwest monsoon season stretches into September.
In the Pacific Northwest, high temperatures and bone-dry terrain have made for dangerous fire conditions, particularly in Washington state. More than 1,600 firefighters labored Wednesday on seven large fire complexes in Eastern Washington that were fanned by high winds earlier this week.
Meanwhile, intense summer thunderstorms that struck parts of the Southwest this week flooded homes and streets in the Las Vegas area, inundated mobile home parks in Southern California, stranded some Navajo Nation residents in Arizona, and broke a dike in southern Utah, leading to evacuations.
The conditions may be leaving residents reeling, but they’re par for the course this time of year, experts say.
Arizona, for example, has seen much flooding in recent months, with normally dry washes rushing like rivers in parts of the state. Some residents might have the impression that this summer has been extremely wet because of the frequency of rain that they can see from their homes, said J.J. Broston, a science and operations officer for the National Weather Service in Tucson.
But rain falls more diffusely across a region — and this year has been wet but not record-breaking, he said.
"For the most part, people are looking at rainfall from their own individual perspectives, and if it rains at their homes, they think it has been a wet monsoon (season)," Broston said. "From the Weather Service’s perspective, we are looking at a larger area."
Rainfall levels in Arizona so far in the monsoon season that runs from June 15 through Sept. 30 have generally been just above average.
Metro Phoenix and surrounding areas have seen 2.35 inches this season, up from the average of 1.4 inches but nowhere near the record of 9.56 in 1984, according to the National Weather Service.
In southern Arizona, the Tucson International Airport has recorded 5.97 inches of rain this season. That’s a half-inch above the average so far in the season, but pales in comparison to the record of 13.84 inches in 1964.
Other southern Arizona cities, however, have seen 2 to 3 inches above their rainfall averages.
In the Las Vegas area, heavy rains this week delayed flights and prompted helicopter rescues of some stranded motorists.
Crews on Wednesday planned to resume their search for a landscape worker who was possibly swept away during a downpour at an area golf course. Police said the man was last seen Tuesday afternoon; photos showed the backhoe he was using almost completely submerged in floodwaters.
More than 1.75 inches of rain was reported in downtown Las Vegas after Tuesday’s showers. That puts the region on pace to exceed the 4.5 inches of rain it normally gets in a year.
In Southern California, a thunderstorm settled for six to eight hours over Mecca and Thermal, two towns 150 miles southeast of Los Angeles near the location of the annual Coachella Music Festival. The storm dropped more than the average annual rainfall on parts of the Coachella Valley in one night alone, flooding two mobile home parks.
Meanwhile, drought-striken New Mexico anxiously awaited the leftovers from the storms that drenched other Western cities.
Meteorologists said an upper-level system moving in from the west was expected to collide with a cold front moving down through the heart of New Mexico.
"This is kind of a unique setup in that we’ve got monsoon moisture in place for these storms to work with," said David Craft, a Weather Service forecaster in Albuquerque. "We are expecting the potential for anywhere from half an inch to an inch and a half of rain across much of northern New Mexico and central New Mexico."
The rain isn’t expected to fall all at once, so forecasters have opted not to call for any flood warnings.
It was a different picture in the Northwest, where fire officials said it could be several weeks before any significant rain or snow dampens the numerous wildfires burning in Washington state.
"While we know we will get a season-ending event in the foreseeable future, it still looks like it’s a little ways down the road," fire spokeswoman Connie Mehmel said.
In Seattle, a rain shower Sunday night dropped the first measurable moisture since July 23 at Sea-Tac Airport, ending a 48-day dry stretch — the second longest on record.
Mehmel said firefighters are stretched thin by the number of large fires in the state, but they’re putting their best efforts into blazes that could threaten people and property.
Some residents just west of Wenatchee were allowed to return home Wednesday, but about 125 homes were still evacuated by a fire that had grown to more than 1,000 acres. Residents of dozens of other homes were told to be ready to flee if the fire grows.
Near Grand Coulee Dam, three homes and nine outbuildings were confirmed lost to two fires that have burned a combined 92,000 acres — or 143 square miles. That fire was 20 percent contained Wednesday.
Meteorologist Brent Bower said August and the first half of September are the driest part of the year for the Pacific Northwest.
This year, though, it’s a bit drier than usual.
"If you’re looking for good summer weather, and if that’s defined by dry and sunny, August and September is what you’re looking for."
He said wet systems are staying away from Seattle, but he expects rain to come back as September progresses. But for now, the sun will keep shining over often soggy Seattle.
"There really is no rain in the forecast," he said.
Billeaud reported from Phoenix. Associated Press writers Manuel Valdes in Seattle and Susan Montoya in Albuquerque, N.M., contributed to this report.