Glen Sampson is the meteorologist in charge at the local office of the National Weather Service, located near the UA. He has been in the meteorology field for 26 years, working at the NWS office in Tucson for the past eight years. The National Weather Service, part of the National Oceanic and Atmospheric Administration government agency, is responsible for setting weather alerts, such as the regular flash-flood watches we see during our monsoon season.

Where are you from originally?

Northern Utah--that's where I went to school. So, I've been in the West basically most of my life, which makes a difference when you're forecasting the weather, because you're dealing with mountains all the time, and that's a lot different than the Plains or East Coast.

We're in the monsoon season now. Why do we have monsoons?

From a data standpoint, I guess as far as how you compare one monsoon to another monsoon, the (monsoon season) dates are June 15 to Sept. 30. ... Then, we don't always have thunderstorms start June 15, so we have kind of a sliding criteria which signifies moisture has moved into the area, and we see a change in the weather pattern and so on. And that's tied to three consecutive days of an average dew point of 54 degrees (or greater) in Tucson, and that signifies the actual start.

What day did the monsoon season officially start this year?

It started on June 18.

Why do the monsoons happen in our area?

It's actually a North American phenomenon--so it's a lot bigger than people think about. We actually see it happen in central Mexico fairly early, and it shifts (upwards), so in a sense, we're (at) the northern end of the whole monsoon pattern.

What about our awesome lightning storms? What conditions cause them?

One of the things about the Tucson area is we have a lot of storms that don't give us (a lot of) rain. When you have conditions like that, you can actually see the lightning better. ... Also, our lightning activity tends to focus around July and August, which means we have it concentrated in a short period of time, which makes it more spectacular.

How large of an area does the Tucson NWS office cover?

We handle the southeastern portion of the state, so that's Pima, Santa Cruz, Graham, Cochise and Greenlee counties and the southeast portion of Pinal. There are actually three Weather Service offices in the state (in Tucson, Phoenix and Flagstaff).

How much computing power do you guys use?

Uh, a lot (chuckles). Well, when you look at the Weather Service as a whole, the way a weather forecast is put together, you basically take all the observations of the atmosphere and use them to initialize a computer program, and it's all governed by mathematical equations. ... Here, we have probably 50 systems; most are for data display.

When did satellites become a part of the Weather Service?

The system architecture we have now was installed in, oh, 1998, so seven years. They've been perpetually upgrading it; we have very few pieces of the original system left. They've been upgrading it, because as technology improves, we try to ride the technology curve.

What is Doppler anyway?

We use Doppler radar, and the Doppler aspect means that you can determine the position of, say, raindrops and how it's moving in respect to the radar. So you can tell whether raindrops (or) hail are moving away from the radar or toward the radar. Now, you take this for an entire thunderstorm, and what that will tell you is the internal structure of the thunderstorm. So when you have Doppler radar, you can see the wind motion of the thunderstorm, and what that will tell you is if the thunderstorm is severe, or what growth stage it's at, or exactly what is happening with that storm

What is necessary to become a meteorologist?

To work for the Weather Service as a meteorologist, you do need a degree. The degree involves a lot of math, so if you don't like math, going into meteorology can by trying at times. So there's a lot of math, a lot of physics ... (it's) how (weather conditions) interact with each other.

How did your interest in weather form?

For myself, I was always interested in science and math, and when I went to college, I looked at careers that were heavy in science and math, and this looked extremely interesting. I got a job with the Weather Service when I got out of school, and here I am now.