Tornadoes are exceedingly rare manifestations of a thermodynamic symphony-remarkable winds born of large storms that themselves tower in size larger than Mount Everest and often wider than Rhode Island is long. Because the conditions that produce them are rare, most tornadoes last less than ten minutes. But in that short time they can cause untold devastation. Storm chasers are hobbyists who relish hunting this elusive and dangerous prey. They also offer a vital link to the science of "tornadogenesis" by helping to verify forecasts and warnings issued by the National Weather Service (NWS).

Chasers must know quite a bit of meteorology in order to position themselves in the right area, often hours before a storm has even formed. In addition, they need to understand a storm's motion and the limitations of the geography. For example, if there are too many hills, it's hard to maintain a safe viewing distance, and it can be difficult to get close to a tornado, or get away from it quickly, in areas without a substantial road network. Needless to say, highly detailed and accurate maps are critical to minimize the chances of being boxed in by a tornado or hydroplaning into a ditch.

In the past, tornado chasing was exceptionally challenging due to the lack of up-to-the-minute data. Chasers would visit their local NWS office in the early morning of the chase day to get the current data on the day's weather conditions. Unfortunately, weather conditions change frequently, and these changes often result in missed opportunities. Today, however, cell networks provide real-time weather data even in remote areas of the Midwest (particularly in the prime chasing real estate known as Tornado Alley). Coupled with GPS, a phone-enabled PDA offers all the versatility a chaser needs to safely chase the tempest.

This tornado stayed over unpopulated areas but produced softball size hail (which ultimately caused more damage than the tornado).

Scoping things out in advance

I fly into Tornado Alley annually at the end of May when the chance to chase supercells, tornadoes, and lightning are at their peak. I am on the road constantly, traveling hundreds of miles a day, going from motel to motel, (camping out in my car when I can't find one) and often rack up 5,000 miles during these two week vacations. Cabled Internet connections can be hard to find, so I rely entirely on my Sprint PPC 6700 Phone Edition Pocket PC to connect to the Web.

The evening before I chase, I spend an hour or two analyzing several megabytes worth of maps and weather data. Given the size of the maps and amount of data I have to study, I use my laptop PC for this. Fortunately, the 6700 can be used as a wireless modem for the laptop. To do this, you need to have Sprint's "Phone as a Modem" data plan, which gives you unlimited data transfers at speeds above 230 kbps. The device achieves high speeds even when I am connection to non-Sprint, 1X CDMA networks. It often exceeds the performance I get through a Wi-Fi connection at motels. To use the Phone as a Modem data plan and access these transfer speeds you need to install a phone dialer application on the laptop PC and install a ROM upgrade on the 6700. The ROM update is necessary because the new software allows data roaming off the Sprint network. Sprint definitely doesn't advertise this key functionality, but it is by far one of the most vital things my PDA provides me.

How to connect the wireless modem to the laptop PC

The phone dialer application is found on the Companion CD that came with the 6700. (On the CD, go to the OEM / APPS / PPC6700SP folder and copy the entire folder to your PC or laptop.) The ROM update can be downloaded for free, but it's a little difficult to find. Go to Sprint.com and search on "downloads." Then, click on the "Software downloads" link and select your operating system (Windows Mobile CE) from the drop-menu. Finally, click on the "download" link next to "PPC 6700 Upgrade Application." (This update only works with the PPC-6700) Download this program and run it on a PC. Follow the onscreen instructions to install the update. Once you've done these two things, follow these instructions:

1. Launch the Comm Manager on your 6700 by tapping on the wireless icon in the bottom right of the Today screen.
2. Immediately interrupt the background data connection by tapping on the second button from the top, on the right side of the Comm Manager screen.
3. On the 6700, go to the Start >Programs folder an open the "Wireless Modem" program.
4. Press the "Start" button at the bottom of the screen. (IMPORTANT: Do this before you connect the 6700 to the laptop PC. Otherwise, the devices may attempt to sync data. )
5. Connect the 6700 to the laptop PC using the USB cable.
6. Launch the phone dialer application you previously copied to the laptop PC from the Companion CD. To do this, double click on the SprintDialer.exe file located in the PPC6700SP folder on the laptop.
7. Press the Dial button at the bottom of the screen. (You do not need to fill in any information on this screen: the application gets it from your phone automatically.) Within seconds you'll see your computer connected to the Internet.

Fig. 1: I extend the range of my Pocket PC's phone with a Wilson Electronics cellular antenna (top). I use a Velcro strip on the back of the Pocket PC to secure the antenna's cable (bottom).

Boosting cell phone reception

The distance between cell towers can be greater on the Plains than in more populated areas of the country. Because of this, I purchased a Wilson Electronics cellular antenna (part number 301103) and adapter (part number 359909) from AccessoryGeeks.com to improve reception (Fig. 1). The antenna adds almost 20 miles' range to my phone reception, which is usually sufficient to keep me connected. It's grounded through a magnetic mount that secures it to my car roof. (Warning: The plug on the antenna cable sticks out a little when it's inserted into the antenna jack on the back of the phone. If you try to push it all the way in, you can damage your phone. I use a Velcro strip to fasten the cable to the back of the 6700. It not only keeps the plug from falling out of the jack, the thickness of the Velcro makes pushing the plug in too far less likely.)

After I'm finished with my initial forecast, I go to sleep, secure in the knowledge that almost everything I've forecasted will have changed by the morning.

Early morning forecast

My Pocket PC is up before I am and has already been hard at work. Using a service called StormNow by DataSwitch (stormnow.com), I receive push e-mails to my Pocket PC with a variety of NWS text reports. StormNow allows me to receive a wide variety of national, state, and county-specific weather bulletins, which can be updated on the fly, easily and quickly, through the Web interface. I can remember several instances where I received a text page on my Pocket PC that arrived prior to the warning information hitting the airwaves! StormNow offers a variety of subscription rates, which start at $2 per month, and depend on the degree of information you need.

Figs. 3 & 4: SwiftMobile Premium displays real-time weather conditions on the today screen (top) and can display animated live radar views of the weather (middle). PocketWeather shows current conditions and forecasts for multiple cities (bottom).

I have two plug-ins for my 6700's Today screen that display excellent overviews of the day's weather. The first is SwiftMobile Premium (swiftmobile.net), a program that gets a lot of "wows" when I show it to people. It comes with a Premium subscription to SwiftMobile ($9.95 per month) and shows current weather conditions with clean iPhone-like icons that summarize real-time weather conditions, alerts, warnings, temperature, and wind speed (Fig. 3). The recently introduced version 1.1 also displays an animated live radar view that can be scaled from county to state level (Fig. 4). It's like having a live Doppler radar right in your holster! (Note that the plug-in does not work properly if you have installed a program that closes programs when you click the X, such as Spb Pocket Plus: spbsoftwarehouse.com).

SwiftMobile was written by Rory Groves, who is also a storm chaser and knows the importance of communicating weather data effectively for chasers in the field. In addition to having real-time storm report information, watch box outlines, radar, and satellite information, SwiftMobile also has a built in GPS overlay that centers your position and allows you to gauge weather situations in your exact location. The interface is highly customizable.

The other weather Today plug-in I use is PocketWeather from SBSH Mobile Software (sbsh.net). It gives me a clean, real-time look at temperature, dewpoint, and forecasts for as many cities as I want (bottom half of Fig. 3 screen). Little-known cool additions (although not relevant to storm chasing) include moon phase information, notifications if an earthquake occurs near one of my preset locations, and notifications of major or destructive earthquakes worldwide. The one-time $9.95 price tag is a great deal and continues a long-standing SBSH tradition of distributing affordable, useful products for the Pocket PC and smartphone. (Special note on Today-screen plug-ins: It's best to install these in main memory. If you install them on a storage card, and the card is not in the slot when the 6700's power on button, you can get the "Black Screen of Death" and have to perform a soft reset.)

The morning of the chase, I'll also open Pocket Internet Explorer (PIE) and head to a very helpful NWS graphic-minimum portal made specifically for small browsers (mobile.srh.weather.gov). At this site, I can read what local forecasters are saying about the day, in several target locations, and factor that into my own forecast.

I'll lug out my laptop at this point to download larger format weather maps, make my forecast, and after that, it's time to travel to my target area, which can be up to 300 miles away.

Arriving at the target before there's a cloud in the sky

Hopping in the car, I begin to listen to books on tape from Audible.com courtesy of portable speakers I plug into my headphone slot (most states make it illegal to drive while wearing headphones). I then connect to my Bluetooth GPS unit and open my Teletype GPS program (teletype.com) while I affix my Pocket PC to its suction mount by RAM Mount (ram-mount.com).

I've used a lot of GPS programs, but Teletype offers the most versatile suite of applications on the PDA with excellent routing options. I especially like the nighttime view that reduces screen glare for night driving. I'm impressed by the detail of Teletype's maps: They often display unnamed and unpaved roads (in chasing jargon they're known as "Bob's Roads" after a line in the movie Twister). I input my destination city and the routing takes seconds. While Teletype offers a weather radar overlay for $39 annually, it is not as feature-rich as SwiftMobile.

Both Teletype and SwiftMobile use GPS data to center my position, which meant I used to have to choose which program I wanted running at any given time because the GPS data could not be shared simultaneously. Fortunately, GpsGate by Franson (franson.com/gpsgate), a three-time Smartphone & Pocket PC Best Software award winner for best GPS utility, offers a software solution that is elegant, small, and effective. GpsGate splits the incoming GPS signal into two "virtual" ports that allows my single Bluetooth GPS to be used by both programs simultaneously. It has a very small memory imprint and I can still use my GPS at the 9600-baud rate.

As I travel, I'll make voice recordings using the built-in recording feature in Notes to record observations about cloud types and surface conditions. I can then click a hardware button in the Teletype program to auto-record my location at the time the note was created. The great part about this is since the Pocket PC records the date and time a note is recorded, I can go back after a chase day and piece together the observations I made temporally and geographically, all of which helps enhance my understanding of the atmosphere for future chase seasons.

Arriving at my initial target in the early afternoon, I use the yellow pages features in Teletype to locate a local restaurant and then hop online using PIE to check out reviews about the restaurant. I've found some amazing local finds and get to enjoy good food instead of standard highway fodder.

During lunch, I'll kick back with a recently recorded TV program using the Orb 2.0 streamer by Orb Networks (orb.com) or I'll watch live TV courtesy of my home PC's TV tuner. It's staggering to note that Orb remains free of charge and allows streaming video and photo content from my home PC. I can even share prior chasing successes with other chasers without having to lug DVDs with me since I can download it to my Pocket PC on the fly!

The chase is on!

With lunch done and storms imminent, it's time to gear up. I make a last minute sweep of current weather conditions and refine my target once more, and then I'm off. Since many chasers also hold amateur radio licenses (me included), I turn on the Ham radio in my car and begin to contact fellow chasers I know to be in the area.

I'm not very good at remembering call signs (the radio contact ID amateur radio operators use to identify themselves), but fortunately my Pocket PC is. When I hear a call sign (say, KB0YJW, my call sign), I use Voice Command 1.6 from Microsoft (microsoft.com/windowsmobile/... to look up who that is. Unfortunately, Voice Command can only look up contacts by name (hopefully someday a search of all fields will be implemented), so I store call signs as "names" with the notes listing to whom the call sign belongs.

Fig. 4: SuperRuler adjusts its scale to the size of your screen and displays an accurate

An unceremonious "THUNK" announces the arrival of hail. With the help of SwiftMobile and Teletype, I navigate to an area where the hail is no longer falling and pull off of the road to check out its size. I measure the hail with a nifty program called SuperRuler (pocketdevelop.com/index.aspx), which I have installed on the 6700 (Fig. 6). SuperRuler displays an accurate ruler on the screen, with metric and standard measurements. The program lets you select the diagonal measurement of your screen and scales the ruler so that it is accurate. The $7.95 utility also includes protractor and remote measurement functions that lets you accurately estimate the size of an object that is larger than your Pocket PC.

I use the Pocket PC a lot, and keep it connected to an external power source when I'm chasing. There are numerous cigarette lighter car charges available, but I prefer to use a power inverter. This type of device connects to your car's 12 volt DC system and converts its current into 110-120 volt AC, which allows you to use home electronics in your car. To have unlimited power for my Pocket PC, I simply plug in my Pocket PC's power adapter into the inverter.

I've used Cobra power inverters for years with excellent results (cobra.com). The more appliances you run off the inverter, the greater the wattage demands. Make sure you get one that can handle what you throw at it. In addition, some inverters connect to the car's cigarette lighter receptacle while others may need to be wired via a mechanic directly to your car's electrical system. Finally, most inverters have built-in electronics to smooth out the current, but surges are still possible. I use a surge protector between the inverter and the appliance to prevent damage.

Fig. 5: A cascade of cloud-to-ground lightning strikes emerge from this radar-confirmed mesocyclone.

The funnel snakes its way towards the ground

"This is KB0YJW reporting a tornado on the ground moving northeast at 20 miles per hour. My current coordinates are"

A rapidly rotating wall cloud develops and radar confirms that this is a mesocyclone. From where I stand, the storm towers over 30,000 feet in the air, the whole mass rotating about a narrow axis (Fig. 6). Thunder booms, the sound of hail recedes in the distance.

Then the prairie is filled with quiet, punctuated by distant rumbles of thunder. It's time to call the NWS and report the condensation funnel I see snaking toward the ground (Fig. 7). The technology has served its purpose. Now I can sit quietly in awed silence, alone with the storm.

I've caught the tempest!