Weather or not? |

Weather or not?

Dan England

Depending on where you were in Greeley on July 25, it was either a typical toaster or the hottest day ever.

It was a scorching 109 degrees at the University of Northern Colorado, official station of the National Weather Service and the one used by the Tribune. It was a little cooler, 102 degrees, at Greeley’s Jackson Elementary School, and at the Greeley/Weld County Airport.

We know. Both temperatures are enough to stuff your clothes full of ice cubes, so who cares? But it’s quite a difference.

For one thing, of course, one temperature gets front-page headlines, usually colored red to show it’s REALLY hot, and heat advisories. The other gets a few sighs from steamed residents.

It shows that, even in a smaller city such as Greeley, one area can be scorching while another can be, well, slightly less sweltering.

Officials from all three stations in Greeley believe their station is accurate, have the equipment to back it up and have good reasons for keeping it accurate. The National Weather Services uses UNC’s site to report temperatures. Jackson Elementary uses its equipment in many lessons, and teachers use it to check to see if it’s OK to have recess outside. The Greeley/Weld Airport uses its own to provide information for pilots, and pilots get pretty cranky if the information is wrong, mainly because that increases the chances for something bad to happen.

Recommended Stories For You

All the weather stations are maintained, and in two cases, at the airport and at UNC, the agencies who installed the equipment do regular maintenance and checks themselves.

So what’s up? Well, it’s not as if the equipment is wrong; it just depends on what surrounds it.

The sun is our generator. It gives us energy. But most of that energy

gets absorbed by the surface, not the atmosphere. And all that energy can be used either to evaporate water or bake the surface.

So if there’s water anywhere, some of that energy is used to make it disappear. The Greeley airport is near the Poudre River, and Sand Creek also seems to cut right through it. The airport also is

surrounded by irrigated land. So it doesn’t get the full brunt of all that surface energy because some of it is being used to evaporate all that water around it.

So that day it was 109 degrees, well …

“We were only 102,” said Mike Reisman, executive director of the Greeley/Weld County Airport. “We were cool.”

There are no rivers near UNC’s station. In fact, things are pretty dry because the station, on the southwest side of Ross Hall, is located near a xeriscape garden.

The station’s been there since 1966, and the university has to get permission from the National Weather Service to move it. The last time that happened was in 1998, when Ross Hall was undergoing an expansion. Considering the weather service allows for a move within five miles and 100 feet of elevation, it’s doubtful that moving the station from one end of Ross Hall to another had much impact.

Still, UNC’s weather students who record the temperatures were amazed at the hot temperatures. The station has two types of thermometers, and the student recording the 109-degree day checked both of them to make sure.

“He didn’t believe it himself when he saw that number,” said Cathy Finley, associate professor of meteorology at UNC, “until he check the second thermometer and saw that it was a half-degree hotter.”

What surrounds a weather station can really throw off the temperature and record a number that doesn’t really reflect the true surface temperature. It’s why the National Weather Service says its stations can’t be near any concrete and prefers a grassy area. The sensor has to be 6 feet off the ground but can’t be too high.

“There used to be a time many years ago when we placed sensors on tops of roofs,” said Byron Louis, program manager with the National Weather Service, “but that was decades ago.”

Terrain plays a role in affecting the surface temperature as well, however. Valleys tend to trap cool air.

“I’ve noticed it biking to Glenmere Park,” Finley said. “You can feel the temperature dropping as you are dropping into that valley.”

Greeley tends to be 5-7 degrees hotter than Denver or Fort Collins. Finley isn’t exactly sure why. Some theories include the fact that Greeley gets less rainfall than those two towns; our soil is drier so it sends more heat in the air; and the clouds may cover those cities more because of the nearby mountains.

At least one company owner admits he likes the hotter weather, and he appreciates those record temperatures because they attract more attention. After all, when you’re an air-conditioning company, 109 degrees in a huge, red headline is the perfect marketing tool.

Greeley Furnace Co., 112 E. 30th St., had to lay some people off in May and June because of the cool months. Then July’s weather started grilling Greeley residents. On a 90-degree day, the company might get 10 calls. If it’s 108, it will get 50 or more.

“All of a sudden, it was like boom,” said Ben Hitchcock, owner of Greeley Furnace. “When it’s above 100, it does our business great.”