Monsoon season can be high-drama crunch time for the Valley’s National Weather Service forecast office.
"It’s pedal to the metal here" many days during the two months of summer when Arizona weather exhibits its most erratic and fierce behavior, said Tony Haffer, who leads a team of 10 meteorologists stationed at the Salt River Project headquarters building in Tempe.
From mid-July to mid-September they’re the sentinels on watch for the massive wind streams blowing moist tropical heat from northern Mexico into a collision with the Southwest’s arid desert climate that can produce blinding dust storms, pounding winds, torrential rains, flash floods and lightning that can spark devastating wildfires.
"It can look like a frantic air-traffic control facility. It gets intense in here,’’ said David Runyan, the warning coordination chief, describing scenes of meteorologists scurrying to track numerous and rapidly developing weather patterns building up around the Valley and threatening to become dangerous monsoon storms.
Working in shifts around the clock, they are launching helium balloons equipped with radio transmitters and sensors to record atmospheric conditions.
They constantly gather data from more than 100 farflung sites where computerized weather monitoring stations are installed. They are viewing up-to-the-minute images and readings from weather satellites and radar systems to analyze cloud concentration, wind velocity and heat buildup.
Little escapes their eyes within their designated monitoring area, which spans from Pinal County across the Valley, reaching hundreds of miles to the Yuma area and to much of the inland desert region of Southern California.
"Sometimes we suffer from information overload. There’s just more information than we can analyze and process quickly enough,’’ Haffer said.
Even with the sophisticated technology and the abundance of data, making accurate forecasts in monsoon season is an educated guessing game.
"There are always weather tendencies, but there are always exceptions to the tendencies,’’ Runyan said. And the monsoon season is the classic manifestation of an atmospherically unstable weather pattern — one in which storm conditions can fizzle out as quickly and unpredictably as they can explode, he said.
"The most certain thing we can forecast this time of year is that there’s the probability of a storm every day,’’ Haffer said.
Sometimes the best they can do is to forecast a dust or thunderstorm’s arrival at any specific location from eight to 15 minutes before it arrives.
But the second they are certain, weather service staff members activate a publicalert system that immediately sends information to public safety agencies, airports and news media.
"The key is to get the word out as early as possible so defensive action can be taken,’’ Runyan said.
For those without access to an emergency weather forecast, he suggests using one rule of simple meteorological observation for safety’s sake.
"If you can hear thunder in the distance, you are close enough to a storm to be struck by lightning. Lightning can reach out as much as 10 miles from the edge of a storm,’’ he said.
Weather service staff members’ awareness of the monsoon season’s deadly potential can make things unusually tense. It’s typically the only time of year that all five forecast work stations in the office will be manned and running at full tilt, Runyan said.
They’re on edge trying to rapidly spot "those three to four severe monsoon events we know we’ll get every year,’’ he said.
As vigilant as the weather watchers are, they often don’t know which storms will turn into monsters until just before they erupt, Haffer said.
But the meteorologists are their own toughest critics, he added.
Every series of forecasts issued when a major monsoon storm occurs is painstakingly reviewed and evaluated for ways to improve future predictions.
"We want the confidence level in our forecasts to increase,’’ Haffer said, because they know a little more accurate information can make a big difference in how the Valley survives its perilously stormy summers.