As you drive north into great falls on I-15, the big white dome off to the right may be given only scant notice. Inside, however, is one of the most sophisticated weather tracking devices in the country. With 150 doppler radars from coast to coast, the National Weather Service is able to track severe weather wherever it is occuring.

But it wasn't until the mid-1990s that Great Falls received its own radar installaion, according to NWS Meteorologist Dave Bernhardt "There were really only two weather service radar's in the state," one in Missoula and one in Billings, "with the expansion of the whole WSR-88D program, then there were radars also put in Great Falls and Glasgow." With that expansion, came upgrades to the nation's severe weather warning system, saving lives by giving advanced warning for tornadoes and other types of severe weather.

The most basic way any radar works is by sending out radio waves and measuring changes to that wave as it encounters objects in the sky whether its rain or hail or even an airplane. In the case of a thunderstorm, the greater the change to the wave, the stronger the storm.

The real key, though, to a doppler radar: by measuring how fast the objects are moving toward or away from the beam, it can detect rotation inside the storm itself - rotation that could eventually lead to a tornado. "We're watching the storm and we're seeing if there's any type of what we call a mesocyclone, which is developing in it," says Bernhardt, "we can have a funnel cloud, which could be spun down, but not actually touching the ground."

The radar here in Great Falls is only able to see one single horizontal slice of a cloud; but upgrades in the final installation stage will allow the radar to see much more about the make-up of a thunderstorm. With the current technology, doppler radar can see the precipitation in a cloud, but not what it is made of. With the dual-polarization upgrade, the radar will be able to tell the difference between raindrops, which are flat, and hail stones, which are not. In a storm where heavy rain is an issue, that could make all the difference between life and death.

According to Bernhardt, "We're going to be able to get a lot more information about the cloud, whatever is in the cloud...not just whether it's a tornado in the cloud. It could also give us additional lead time for issuing tornado warnings because we'll be able to get more information about what's in the cloud."

And in a state where weather can change in seconds, the more lead time, the better.