WILLIAMS, Ariz. - According to Brian Klimowski, meteorologist in charge of the National Weather Service (NWS) office in Bellemont, predicting the weather is a tricky business. He explained the challenges of predicting the weather in a speech to the Williams Rotary Club Feb. 21.
The Bellemont office is one of 122 NWS offices nationwide. Eleven full time meteorologists in Bellemont forecast the weather for all of northern Arizona, starting from about 60 miles north of Phoenix but excluding Mohave County.
Klimowski began by explaining that the large storm forecast to hit Williams last week ended up shifting 50 to 100 miles south. Flagstaff received 3 to 6 inches of snow, rather than the 6 to 10 inches the NWS originally forecast.
"Forecasting the weather is somewhat analogous to trying to forecast where the location of a leaf is going to be if you drop it in a rocky stream," Klimowski said.
Weather forecasting has several components, according to Klimowski. The first is observing what is currently happening. The NWS has about 700 volunteer observers in northern Arizona to help with this process. Another component is using weather radar. A third component is using numerical models, in which computers simulate what is going to happen in the weather.
The NWS uses six primary weather forecast simulations.
"It's up to the meteorologist to use his experience and insight and knowledge of the local conditions to say I believe this set of solutions but I don't believe this set," Klimowski said. "Because we're all human, there's different opinions on weather."
The different computer weather simulations each solve various meteorological problems differently, Klimowski said.
"The weather is fluid and math is finite," he said. "Math can't fully explain the mechanisms behind this atmospheric fluidity we call weather."
Choosing the most accurate scenario from the different computer simulations is one of the challenges of weather forecasting.
"There is no one finite solution to any meteorological problem," Klimowski said. "However, there's likelihood and probability, and that's why the weather service operates on likelihood and probability."
Klimowski said NWS has started focusing on decision support services, "which describes us communicating our message most effectively to decision makers in the community." NWS uses emails and conference calls to inform groups like emergency managers, street crews and Arizona Department of Transportation officials (ADOT) about the weather it is anticipating.
Making accurate predictions about the weather is important.
For example, in anticipation of last week's storm, Northern Arizona University canceled classes. However, the storm turned out to be less severe than meteorologists predicted.
As another example, Klimowski explained that in some cases ADOT moves resources from Phoenix northward if forecasters anticipate a large storm. If the prediction is wrong, those resources are in the wrong place.
"A missed forecast in one area can have impacts in a different area," Klimowski said.
In the future, the NWS may start using social media to help in communicating weather information.
"It's incumbent on us at the National Weather Service to make sure that our message is clear, concise, prevalent and consistent so we can be a sole source of accurate weather information," Klimowski said.