1. If I don’t fly IFR or whenever there are Thunderstorms, how can Stormscope help?
Stormscope is just as useful for VFR flying, especially if you are going to get full utilization of your aircraft. During the thunderstorm season forecasts of widespread/isolated thunderstorms covering huge areas are common – often the trip out in the morning is beautiful, but the return trip later in the day is dotted with CU’s and the possibility of CB’s. By mapping lightning strikes, Stormscope will enable you to identify if thunderstorms are actually out there within a range of 200 nm in all directions. This is an especially useful tool when visibility is just a few miles in haze. There are days when the forecast calls for the potential of thunderstorms and they are isolated, widely scattered or they don’t develop at all. Other times thunderstorms develop quickly on a day when they are not forecast. Stormscope provides you with information that will enable you to make better informed thunderstorm decisions on the ground before take-off and in the air. It will enable you to make en route decisions that might be a simple deviation around an isolated cell, or to land and wait it out on the ground.
2. Which system is the better choice for me?
Ideally, having both systems is the better choice. Stormscope will not replace Datalink, nor will Datalink replace Stormscope. Lightning, by definition, signifies the beginning and most dangerous phase of a thunderstorm. Severe turbulence with up and down drafts existing within them has been the cause of many in-flight aircraft breakups. Only a spheric detector like the Stormscope maps ALL stages in the life of a thunderstorm and all stages present hazards to aircraft. Datalink weather provides year-round weather tools including METAR, TAF, TFR, SIGMET, AIRME, Winds Aloft, etc. All are wonderful tools to the pilot. Their Nexrad imagery however, only shows precipitation, which is NOT always associated with thunderstorms. Even during thunderstorms, the beginning of the precipitation signifies the ending or dissipating stage. So in conclusion, Stormscope tells you, without any delay, where the building thunderstorms are. Nexrad shows precipitation and when it is associated with a thunderstorm, you can see where that storm is dissipating. The two technologies are the perfect complement to one another.
3. If I have Datalink weather, why would I need Stormscope?
Radar shows precipitation. Stormscope detects and maps lightning created by areas of strong updrafts/downdrafts. These two pieces of information are different and one does not duplicate the other. Lightning strikes occur in the developing or cumulus state of a thunderstorm – this is before falling precipitation exists to be mapped via Datalink WX. The initial stage of a thunderstorm contains many WX hazards that are dangerous to aircraft (strong vertical winds, severe turbulence, icing, convective wind sheer and lightning). The Stormscope locates these building thunderstorms by detecting the electrical discharges they always generate. Because the cumulus stage of a thunderstorm is usually precipitation free, it is rarely visible on the Datalink Nexrad image. The Stormscope is also a useful tool to enable you to determine if it is safe to fly through an area of rain showers. For example, you may consider flying through an area of heavy rain showers if no lightning is present. Finally, there are inherent delays with Datalink WX. Thunderstorms are very dynamic and a lot can happen during that delay period. Data is 3- to 9-minutes old before it reaches the aircraft (collection, processing, travel) and then remains on the display in your aircraft for 5 or more minutes. The AIM, NASA and NOAA sources all maintain that a thunderstorm can build mature and dissipate in as little as 20 minutes. Think of Datalink Nexrad and text weather as a strategic tool, and Stormscope as a tactical tool. Strategic tools are good for planning 100-miles out. Tactical tools are key to navigating the next 25-50 miles ahead.
4. Isn’t Datalink lightning the same as Stormscope lightning?
No, they are actually showing different information. Stormscope shows all lightning in real time. The lightning which is being offered by some Datalink providers is cloud-to-ground lightning only. (This is provided by the National Lightning Detection Network – NLDN). There are two very important things to consider regarding this cloud-to-ground lightning. First, cloud-to-ground lightning often occurs during the dissipating stages of a thunderstorm (where the heaviest rain begins to fall). Source: NASA. Second, cloud-to-ground lightning makes up only 10-20% of the TOTAL lighting that occurs during a thunderstorm. Source: NOAA.
5. Why is that significant?
If you are not seeing cloud-to-cloud and intra-cloud lightning, you risk flying into a thunderstorm. According to Dr. Hugh Christian, “storms with the greatest vertical development may produce intra-cloud lightning almost exclusively.” 1
6. If I can have only Datalink WX or Stormscope, which should I choose?
Your choice depends on the type of flying you do, the type of pilot you are, and where you live. For example, if you tend to fly more during the spring and summer months than you do in winter, then the Stormscope may be the best choice for you. If you are the type of pilot who has to get full utilization out of the aircraft and fly on any mission profile, then the ideal situation is to have both systems.
7. How does the cost of Stormscope compare to most Datalink systems?
Each system requires initial purchase of a receiver and antenna that needs to be installed into your airplane. The primary difference is that there is no subscription cost associated with Stormscope. Datalink WX subscriptions cost $600 to $700 annually for unlimited use and all features.
8. Sometimes I see lightning strikes on my Stormscope in an area where there is no precipitation mapping on my Datalink map, why would this occur?
Lightning is present in the beginning, or the cumulus stage of a thunderstorm which is typically precipitation-free. Therefore, it would be accurate to see strikes on Stormscope and no precipitation mapped on a Datalink Nexrad display.
9. Does the Stormscope show lightning that occurs before Nexrad information is available?
Yes. Most often during the cumulus stage of a thunderstorm because this stage is usually precipitation-free.
10. How much lightning occurs before the precipitation and echo tops show up on Datalink Nexrad?
That’s really dependent on the stability of the air and particularly on how quickly the thunderstorm goes through its various life cycles: cumulus, mature and dissipating stages.
11. Why don’t I see strikes on Stormscope associated with Nexrad showing a high echo top?
When electrical discharges no longer occur in a CB, there are no strikes to map on the Stormscope. In the dissipating stage of a thunderstorm, the convective wind sheer and other hazardous conditions begin to subside. There may be high rainfall rates in this stage, but the severe dangers are diminishing. You may wisely choose not to fly into a towering CU despite a lack of lighting. Combining the information supplied by Stormscope with Datalink Nexrad will enable you to better determine if a safe path exists through an area of weather or if it is an impenetrable line.
12. How frequently does Stormscope update?
The WX 500 Stormscope processor updates the MFD every 2 seconds with all the strikes that were detected since the last update. Each strike remains on the display for approximately 3 minutes. Where lightning strike rates are very high, older strikes may be removed from the display in less than 3 minutes to give priority to newer strikes.
13. What is the difference between Cell and Strike mode?
Cell data uses a clustering algorithm to locate storm cells. Cell data is most useful during periods of heavy electrical discharge activity. Display cell data during these periods allows the pilot to quickly see where the cells are without having to sift through and analyze a screen full of discharge points. Strike data is most useful during periods of light electrical activity because strike data may show the initial discharge associated with a building thunderstorm sooner than cell data would. The WX 500 and WX 950 plots strike discharge points in relation to where the discharges are actually detected instead of plotting them close to an associated group of discharge points as is done with cell data.
14. Does Stormscope detect intra-cloud and cloud-to-ground lightning?
Yes. Stormscope detects the electric and magnetic fields generated by intra-cloud, inter-cloud and could-to-ground electrical discharges that occur within a 200 nm radius of the aircraft.
1 Lightning Detection From Space, A Lightning Primer, Dr. Hugh J. Christian, Senior Scientist, Marshall Space Flight Center, AL, NASA, Melanie A McCook, Senior Research Project Coordinator, University of Alabama in Hudsonville