By Bill Kelly, STATEWIDE Correspondent.
A sticky summer afternoon in the middle of North Platte's Nebraskaland Days. It's the biggest tourist event of the year. A beautiful, hazy day that might get interesting. A thunderhead 150 miles away in Garden County can already be seen on the horizon. No one is more interested than the forecasters at the National Weather Service. Their office -- by the airport.
[Unidentified weather announcer] "We're expecting potential for hail surfacing with a latitude of two inches with wind gusts to over 80 miles an hour..."
Weather watches are issued by the main forecast center in Oklahoma. Conditions are ripe for summer storms and perhaps tornados across much of Nebraska for the rest of the day.
[Dave Wert, meteorologist in charge] "You can see it covers all of the panhandle in the western part of the state."
From this point on, the full responsibility for issuing local storm warnings for 23 central Nebraska counties will lie solely with the North Platte team. The atmosphere outside is unstable setting the stage for potentially violent weather.
[Wert] "As a matter of fact, the way -- it's like popping a balloon. You don't know when it's going to pop but when it happens, it happens very quickly. And the atmosphere is the same way.
Dave Wert is the meteorologist in charge."
[Wert] "One of these things which looks very benign right now, 15 minutes from now could be producing dime size hail or even something larger. It's going to be pretty active."
For the team on duty this afternoon, the equipment ranges from the less than ideal computers assembled in the 1970's to the latest doppler radar that pinpoints the inner workings of a weather system in nearly every way possible. That radar has been tracking a fairly intense thunderstorm across the panhandle. Until now the storm cell has been the responsibility of the weather service office in Cheyenne, Wyoming. As it crosses into Garden County, Nebraska it's on the turf of the North Platte forecasters. Today's first warning is based on a combination of facts about today's weather conditions -- the forecaster's knowledge of how the weather works combined with logical guesswork done by sophisticated computer models and math work.
[Wert] "So you have to do some type of extrapolation and use sound physical principles to try to anticipate well, this is what I'm seeing, this is why I'm seeing it, and this is what is most likely to occur. And that's where the forecasting. It's just as much an art as it is a science still."
Shortly after the storm belts Oshkosh, Nebraska, it huffs and puffs and blows itself out. But as the evening shift arrives for their briefing, there are new storms already percolating.
[John Stoppkotte, meteorologist] "S.P.C. when they coordinated with me said they expect those things just to explode all along that frontal boundary which would be right along in through here. Here in this case is an area where data collected from weather balloons and satellite data show conditions providing pockets of warm moist air needed to give power or lift for brewing thunderstorms."
[Unidentified weather service worker] "The best potential for severe thunderstorm development would be kind of along the South Dakota-Nebraska border. Everything kind of looks like it's pointing in that same direction. Where the tightest circles are."
[Unidentified weather service worker] "Where you have the dashed green there is where we have actual forcing going on which contributes to the lift. Best potential would be right there."
The result is this storm, powerful but unstable heading for Nebraska. There's enough momentum, hail, wind, and lightening to warrant a severe thunderstorm warning for the county and its path.
[Theresa Wood, lead meteorologist] "Let's just put Sheridan in there for now because the way that they've been pulsing up and down, it could fall apart long before it gets to Cherry."
The forecasters will hold off on warning other counties until they get a better read on the storm's development. Reports from volunteer spotters in the field hint that storm is becoming more powerful. This is how the storm looks on radar, and this is the same monster storm to the north of Hay Springs.
[Unidentified weather announcer] "At 3:38 p.m. Mountain Daylight Time a severe thunderstorm was indicated by North Platte Doppler Radar..."
These are recorded weather announcements that interrupt many local radio and television broadcasts.
[Unidentified weather announcer] .".. Damaging hail and/or destructive winds can be expected near White Clay by 3:45 p.m. Mountain Daylight Time."
The teletype versions are the raw material used by TV weather casters when they go on the air to warn their viewers of severe weather.
[Unidentified weather announcer] .".. If you are in the path of this storm, you should move inside a strong building and go to the lowest floor possible."
That warning gave the people in the tiny border town of White Clay a full nine minutes advanced warning. So far the forecasters prove to be precise to the minute. They know because they check while the storms are still on the move.
[Sheri Mutchler, meteorology intern] "You didn't have any hail? I heard there were some reports of wind and other things with it."
Using a master list of phone numbers for nearly every darn home and business in rural Nebraska, an intern makes a quick call to White Clay.
[Mutchler] "We don't have any numbers for White Clay. I knew there was a cafe there, the Jumping Eagle Cafe -- or the Jumping Eagle Inn and I got their number from information, happened to call them, happened to hit just the right person who had a report of hail that had occurred there in the past five minutes. That verifies our storm warning that tells us we put out a good warning."
[Wert] "What do you think the largest size hail was?

With radar only able to measure the inside of the storm at thousands of feet in the air, the phone calls to and from ground spotters are the forecasters' eyes miles away from their computers.
[Wert] "5:15, six north of Gordon, one-inch of hail. He is in an excellent viewing angle for that storm. He said there's no appendage at this point. A lot of turbulence in the clouds but he's going to keep an eye on it and tell us if he sees the funnel drop."
[Mutchler] "There is no substitute for actual human eyes when it comes to storms and tornados."
The storm is only getting more powerful. The lead meteorologist calls it a classic system.
[Wood] "It's not showing any trend really of weakening right now. Within 15 minutes it's going to go into northwestern Cherry County."
[Unidentified weather announcer] "Attention, Valentine warning point, this is the National Weather Service in North Platte."
As the storm moved into Cherry County, it divided and multiplied into four separate large storms spread across Nebraska's largest county. Here the warnings are split as well since different storms are hitting different parts of Cherry at different times.
[Wood] "We're going to have to go ahead and warn on that one, too."
Each cell has to be tracked independently for signs of it intensifying or even spawning a tornado. It's called a convective complex, and it's likely to have a very long life.
[Wert] "This will be continuing all night long as it moves to the east-southeast into eastern Nebraska and then ultimately into Iowa. So by tomorrow morning and even around noon, you will probably see this thing 3, 400 miles to the east of us and still in tact."
Again, the computer model showed this storm could produce huge hail. Each of the tiny triangles pinpoint where people and crops are likely getting hammered. One estimates three-inch hail stones.
[Wert] "That's for northcentral Cherry and your expiration is 6:55."
Outside a weather balloon launch is being coordinated with weather monitoring stations around the world. At exactly 6:00 p.m., the balloon races to the northeast. The remote control sensors attached to the back send information about wind speeds and temperatures in the upper atmosphere, the type of baseline data that can help make sense of a fast brewing storm like the one now visible on the horizon hovering over Duel County.
[Wood] "Did the balloon head far enough to find out what the freezing levels are?"
As if keeping track of four separate storms in Cherry County was not enough, an entirely new complex had cropped up to the south. Five storms to keep track of at once, four of them in one county.
[Kelly]"You stay awfully calm with all that at stake."
[Stoppkotte] "Well, I guess I've just been doing it a long time. I just -- I've been in this for 23 years so almost all working severe weather radar."
[Kelly]"Does it ever scare you?
[Stoppkotte] "If it does, I kind of keep it down. I get kind of -- my stomach gets to churning sometimes and then when I get home, it takes a while to settle down."
[Wood] "Whenever you got the report, you feel for the people that are there. I get a rush from it."
[Kelly]"What's the rush feel like?"
[Wood] "Just your bloods a pumping. You get excited. You're alert to what's going on. Especially when the damage reports start coming in. When you're concerned for other people in an environment where that's happening."
[Wert] "There's an adrenalin rush. I think you need that to keep the edge. Very frequently people will be here 8, even 10 hours working at a frenzied pace. You need to have that adrenalin to keep yourself going and to keep sharp so you're not missing something that might ultimately impact a person's life."
[Unidentified weather announcer] "... In Southwestern Nebraska, Eastern Perkins County..."
As the new storm moves into adjoining Perkins County, new warnings are issued.
[Unidentified weather announcer] "... 21 miles south-southeast of Ogallala.
The radar shows it but now the storm is literally at their back door, and some forecasters spend as much time watching out the window as others do watching radar screens. What they see is an ominous wall cloud appearing to the west."
[Wert] "This is a perfect opportunity to see a super cell in action.
For a few brief moments, it looks like a tornado may drop out of the sky within site of the Weather Service office."
[Wert] "What you have is you got the inflow into the base of the storm and it's turning like this. So as it turns, it throws the hail downstream to the north so you can see all the fuzz which is the rain falling, and right on the intersection where you have the updraft which is rotating, you have that lowering of the cloud base which we call the wall cloud."
A minute later the storm simply collapses losing all its energy. It's become little more than a gully washer.
[Wert] "Well, all the warnings for Cherry County have expired. There still is scattered convective activity up there, some of which is strong, but most of the real nasty stuff moved further to the east into northcentral Nebraska."
[Stoppkotte] "This cluster, all the storms seem to be decreasing in intensity right now, but the air is still unstable out there so they could fire up again later."
Outside the forecast office, the wind is picking up and the rain is moving in. The next round of storms are brewing to the west. A whole new set of warnings one right after another will come out of the North Platte Weather Service office all night long.

Captioning by Nebraska Captioning Center, Lincoln, Nebraska .