How lightning strikes can improve storm forecasts


Humans have always been frightened and fascinated by lightning. This month, NASA is scheduled to launch a new satellite that will provide the first nonstop, high-tech eye on lightning over the North American section of the planet.

University of Washington researchers have been tracking global lightning from the ground for more than a decade. Lightning is not only about public safety — lightning strike data have recently been introduced into weather prediction, and a new UW study shows ways to apply them in storm forecasts.

“When you see lots of lightning you know where the convection, or heat-driven upward motion, is the strongest, and that’s where the storm is the most intense,” said co-author Robert Holzworth, a UW professor of Earth and space sciences. “Almost all lightning occurs in clouds that have ice, and where there’s a strong updraft.”

The recent paper, published in the American Meteorological Society’s Journal of Atmospheric and Oceanic Technology, presents a new way to transform lightning strikes into weather-relevant information. The U.S. National Weather Service has begun to use lightning in its most sophisticated forecasts. This method, however, is more general and could be used in a wide variety of forecasting systems, anywhere in the world.

The authors tested their method on two cases: the summer 2012 derecho thunderstorm system that swept across the U.S., and a 2013 tornado that killed several people in the Midwest.

“Using lightning data to modify the air moisture was enough to dramatically improve the short-term forecast for a strong rain, wind and storm event,” said first author Ken Dixon, a former UW graduate student who now works for The Weather Company. His simple method might also improve medium-range forecasts, for more than a few days out, in parts of the world that have little or no ground-level observations.

The study used data from the UW-based WorldWide Lightning Location Network, which has a global record of lightning strikes going back to 2004. Director Holzworth is a plasma physicist who is interested in what happens in the outer edges of the atmosphere. But the network also sells its data to commercial and government agencies, and works with scientists at the UW and elsewhere.

A few years ago Holzworth joined forces with colleagues in the UW Department of Atmospheric Sciences to use lightning to improve forecasts for convective storms, the big storms that produce thunderstorms and tornadoes.

Apart from ground stations, weather forecasts are heavily dependent on weather satellites for information to start or “initialize” the numerical weather prediction models that are the foundation of modern weather prediction.

What’s missing is accurate, real-time information about air moisture content, temperature and wind speed in places where there are no ground stations.

“We have less skill for thunderstorms than for almost any other meteorological phenomenon,” said co-author Cliff Mass, a UW professor of atmospheric sciences. “This paper shows the promise of lightning information. The results show that lightning data has potential to improve high-resolution forecasts of thunderstorms and convection.”

The new method could be helpful in forecasting storms over the ocean, where no ground instruments exist. Better knowledge of lightning-heavy tropical ocean storms could improve weather forecasts far from the equator, Mass said, since many global weather systems originate in the tropics.

The study was funded by NASA and the National Oceanic and Atmospheric Administration. Greg Hakim, a UW professor of atmospheric sciences, is the other co-author.

The Worldwide Lightning Location Network began in 2003 with 25 detection sites. It now includes some 80 host sites at universities or government institutions around the world, from Finland to Antarctica.

The latest thinking on how lightning occurs is that ice particles within clouds separate into lighter and heavier pieces, and this creates charged regions within the cloud. If strong updrafts of wind make that altitude separation big enough, an electric current flows to cancel out the difference in charge.

A bolt of lightning creates an electromagnetic pulse that can travel a quarter way around the planet in a fraction of a second. Each lightning network site hosts an 8- to 12-foot antenna that registers frequencies in the 10 kilohertz band, and sends that information to a sound card on an Internet-connected laptop. When at least five stations record a pulse, computers at the UW register a lightning strike, and then triangulate the arrival times at different stations to pinpoint the location.

The network’s online map shows lightning strikes for the most recent 30 minutes in Google Earth. An alternate display shows the last 40 minutes of lightning in different parts of the world on top of NASA cloud maps, which are updated from satellites every 30 minutes. The program is the longest-running real-time global lightning location network, and it is operated by the research community as a global collaboration.

Lightning already kills hundreds of people every year. That threat may be growing — a recent study projected that lightning will become more frequent with climate change.

“The jury’s still out on any long-term changes until we have more data,” Holzworth said. “But there is anecdotal evidence that we’re seeing lightning strikes in places where people are not expecting it, which makes it more deadly.”

On Nov. 19, NASA is scheduled to launch the new GOES-R satellite that will be the first geostationary satellite to include an instrument to continuously watch for lightning pulses. Holzworth will help calibrate the new instrument, which uses brightness to identify lightning, against network data. NASA also funded the recent research as one of the potential applications for lightning observations.

“GOES-R will offer more precise, complete lightning observations over North and South America, which will supplement our global data,” Holzworth said. “This launch has been long anticipated in the lightning research community. It has the potential to improve our understanding of lightning, both as a hazard and as a forecasting tool.”



The Impact of Lightning Data Assimilation on Deterministic and Ensemble Forecasts of Convective Events

A general lightning data assimilation technique is developed and tested with observations from the World Wide Lightning Location Network (WWLLN). The technique nudges the water vapor mixing ratio toward saturation within 10 km of a lightning observation and is more general than other approaches that require specific model microphysics or flash rates. This approach is applied to both deterministic and ensemble forecasts of the 29 June 2012 derecho event over the eastern United States and a deterministic forecast of the 17 November 2013 convective event over the Midwest using the Weather Research and Forecasting (WRF) Model run at a convection-permitting resolution. Lightning data are assimilated over the first three hours of the forecasts, and the subsequent impact on forecast quality is evaluated. For both events, the deterministic simulations with lightning-based nudging produce more realistic predicted composite reflectivity fields. For the forecasts of the 29 June 2012 event using ensemble data assimilation, forecast improvements from lightning assimilation were more modest than for the deterministic forecasts, suggesting that lightning assimilation may produce greater improvements in convective forecasts where conventional observations (e.g., aircraft, surface, radiosonde, satellite) are less dense or unavailable.


29 thoughts on “How lightning strikes can improve storm forecasts

  1. Lightning already kills hundreds of people every year. That threat may be growing — a recent study projected that lightning will become more frequent with climate change.”

    Classic Alarmist statement. Send money.

    Change out the two occurences of “lightning” above with other deadly weather phenomena:
    extreme heat, extreme cold, extreme drought, extreme rainfall, extreme tropical storms.

    When a hypothesis (for example: anthro Climate Change) can “predict” any conceivable outcome, it is not scientific. It is pseudoscience crap.

    Disclaimer: the above comment does not in anyway mean I think lightning research and improving forecasts with the data is not a valid and important research area. It is. Just cut-out the nonsense, alarmist climate change linkage crap.

    • It does get like the old Soviets mentioning the class struggle in a paper on an unrelated subject. It is a good thing to actualy see the NOAA studying weather, and how better to predict it.

      • So it takes lots of convection within clouds containing ice crystals to generate lightning. Global warming will equate with more lightning. So global warming must cause more ice to form in clouds

  2. One of my favorite subjects – lightning. I have studied it and photographed it since i was knee-high to a grasshopper. And now live in the lightning capital of North America. (Just coincidence) So, “…a recent study projected that lightning will become more frequent with climate change.” Does anyone know what “study” they are referring to?

    • Um, er ! please sir, If there are lightning strikes, isn’t it a tad on the late side to be ” forecasting ” a storm coming; like it’s already arrived ??


      • George e. smith, actually, in this case, we aren’t talking about where the storm currently IS, we’re talking about where it may be & how intense it may be up to days later, after it’s moved on from where it is now. (This did give me a chuckle though, reminding me of the old U.S.A.F. Weather Prediction Tool. ~_^)

        It’s one thing to look at a current sat photo & weather map and see that there’s rain falling in a given spot, the winds are blowing in thus-&-such direction, and make a forecast. It’s another thing entirely to be able to take all of that AND THEN factor in whether or not lighting is present, how much there is, how strong/what charge it is, where in the circulation it’s most concentrated, and so on. These give lighting cues provide clues that even hi-res Doppler radars have trouble finding, and watching how the lightning distribution changes over time can give clues to the eventual development or collapse of a given system dozens-to-hundreds of miles and hours-to-days later.

        An added feature is that since lightning detectors actually can detect & pin-point strikes that occur anywhere in the world, one need not be anywhere near the system in question to track its lightning strike data. This is why they said in the article that it could be a big help in narrowing down the estimates & forecasts of storm development in tropical systems far from land, where no/few hurricane hunter flights or passing ships have been.

      • Lightning strikes create an electric impulse which has a frequency spectrum that is quite broad and is at audible frequencies.
        At the strike location, of course you just get a crash, if you put up a long wire antenna and hook it to the front of a hi fi amplifier.
        But that blip propagates around the globe using the ionosphere and also the magnetic field of the earth, so somewhere at the other end of the earth the pulse arrives later but it’s frequency spectrum has been affected by chromatic aberration so the different audio frequencies propagate at different speeds.

        Sometimes the low frequencies can travel fastest, and sometimes the high frequencies are faster.

        The result is a chirped whistle that either slews up or down in frequency over time.

        Then those waves reflect off the ground, and head off back to where they came from, becoming further dispersed in frequency, so they arrive back at their origin smeared out further. They can bounce back and forth a number of times, getting weaker and weaker with each transit.

        But two receiving stations at opposing locations, can record these whistlers or howlers and the time they arrive.

        When I worked a summer at the DSIR near Wellington, we were paired with a station in Norway or Iceland or somewhere over there, so we were monitoring these strike whistles, and comparing notes so we could identify the interlaced rebounds across the radio path between us.

        From the frequency slewing we could calculate the electric charge distributions through the ionospheric regions between us.

        Well when I say, we could, I mean the guys doing the studies could. I just listened to the chirped whistles in total amazement.


  3. “— a recent study projected that lightning will become more frequent with climate change.”

    I wish they had included a link to check that out…

  4. Have we really run out of material?….
    It’s getting more common now to see recycled “discoveries”…

  5. They have set up a system to look for lightning (why the visible spectrum?) and then triangulate its location. How is this predicting anything? All that was accomplished was to find the storm. I suppose the could then monitor the movements of the storm to “predict” its next position.

  6. Lightning is natures way of creating electrical balance between Earth and atmosphere . Man made RADIOACTIVITY created at the surface needs to be seen as a driver for the change in weather extremes around the world.

    “The global atmospheric electrical circuit is the continuous movement of electric current between the ionosphere and the earth’s surface. This flow is powered by thunderstorms, which cause a build-up of positive charge in the ionosphere. In fair weather this positive charge slowly flows back to the surface.
    The voltages involved are significant. At sea level, the typical potential gradient in fair weather is 120 V/m. Nonetheless, since the conductivity of air is limited, the associated currents are also limited. A typical value is 1800 A over the entire planet.

    Thunderstorms generate an electrical potential difference between the earth’s surface and the ionosphere, mainly by means of lightning. Because of this, the ionosphere is positively charged relative to the earth. Consequently, there is always a small current transporting charged particles between the ionosphere and the surface. Since air is a good insulator, this current is carried by a small number of ions present in the atmosphere (generated mainly by cosmic rays in the upper atmosphere, and by RADIOACTIVITY near the surface).

    In electrical engineering, ground or earth is the reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth.
    In electrical power distribution systems, a protective ground conductor is an essential part of the safety Earthing system ”

  7. I spoke with an engineer who told me about use of this RF phenomenon to predict tornadoes. They were working with it back beginning at least as far back as the late 1970s. They were enlisting hams to triangulate along with doppler radar. Adding satellite sensors should certainly improve the results.

  8. “Lightning already kills hundreds of people every year. That threat may be growing — a recent study projected that lightning will become more frequent with climate change.”

    Usual typical nonsense mentioned with anything that happens. The truth is it may do this because we don’t know and have no evidence to back it up.

    Climate change, meaning global warming, meaning a planet that is suppose to warm not just by El Nino’s has no mechanism to support this at all.

    A warmer planet has less temperature difference between colder zones and the hotter zones. Less difference in temperature leads to less severe weather.

    North America has some of the most severe weather because of cold air from Canada meeting warm air from the sub-Tropics. Reduce the difference here and the climate becomes less severe like over Europe.

    Basic explanation below:-

    Thunderstorms can form and develop in any geographic location but most frequently within the mid-latitude, where warm, moist air from tropical latitudes collides with cooler air from polar latitudes.[2] Thunderstorms are responsible for the development and formation of many severe weather phenomena. Thunderstorms, and the phenomena that occur along with them, pose great hazards. Damage that results from thunderstorms is mainly inflicted by downburst winds, large hailstones, and flash flooding caused by heavy precipitation. Stronger thunderstorm cells are capable of producing tornadoes and waterspouts.

    Some of the hottest places in the world especially around the Middle East and most desert regions have no or little thunderstorm threat due to very limited much cooler air been able to reach there.

    • Central Florida is the lightning capital of the Western hemisphere. It has nothing to do with climate change pseudoscience.

      The authors could simply have left out the call-out to Climate Change.

      He auors fall prostrate before the false idol of Climate Change, recite their affirmation of faith, then hope for a few pieces of gold come their way. Gold extracted by force from the labors of the workers.

  9. Using radio waves to detect lightning is old. Alexander Popov built a lightning detector in 1895. link

    As far as I can tell, NexStorm has been available, since before 2007, to do what the UW folks are doing.

    • commieBob, the only thing UW is doing differently is incorporating that data into their forecasting algorithms. The method is, as you put it, old news; the application is what’s new.

  10. Part of understanding lightning and when and where it will it will occur is understanding the different incoming particle populations that can affect the global electric circuit.
    Quote from the abstract below.

    “”lightning rates vary with galactic cosmic ray (GCR) flux incident on Earth, either via changes in atmospheric conductivity and/or direct triggering of lightning.””

    Modulation of UK lightning and the atmospheric electric circuit by heliospheric magnetic field polarity
    Owens, Mathew; Scott, Chris; Lockwood, Mike; Barnard, Luke; Harrison, Giles; Nicoll, Keri; Watt, Clare; Bennett, Alec


    Observational studies have reported solar magnetic modulation of terrestrial lightning on a range of time scales, from days to decades. The proposed mechanism is two-step: lightning rates vary with galactic cosmic ray (GCR) flux incident on Earth, either via changes in atmospheric conductivity and/or direct triggering of lightning. GCR flux is, in turn, primarily controlled by the heliospheric magnetic field (HMF) intensity. Consequently, global changes in lightning rates are expected. This study instead considers HMF polarity, which doesn’t greatly affect total GCR flux. Opposing HMF polarities are, however, associated with a 40 to 60% difference in observed UK lightning and thunder rates. As HMF polarity skews the terrestrial magnetosphere from its nominal position, this perturbs local ionospheric potential at high latitudes and local exposure to energetic charged particles from the magnetosphere. We speculate as to the mechanism(s) by which this may, in turn, redistribute the global location and/or intensity of thunderstorm activity.

    To help understand what that population of incoming particle fluxes are…
    See the acronym list after the abstract below..

    Space Science Reviews
    November 2015, Volume 194, Issue 1, pp 1–96
    Energetic Particle Influence on the Earth’s Atmosphere

    This manuscript gives an up-to-date and comprehensive overview of the effects of energetic particle precipitation (EPP) onto the whole atmosphere, from the lower thermosphere/mesosphere through the stratosphere and troposphere, to the surface. The paper summarizes the different sources and energies of particles, principally galactic cosmic rays (GCRs), solar energetic particles (SEPs) and energetic electron precipitation (EEP). All the proposed mechanisms by which EPP can affect the atmosphere are discussed, including chemical changes in the upper atmosphere and lower thermosphere, chemistry-dynamics feedbacks, the global electric circuit and cloud formation. The role of energetic particles in Earth’s atmosphere is a multi-disciplinary problem that requires expertise from a range of scientific backgrounds. To assist with this synergy, summary tables are provided, which are intended to evaluate the level of current knowledge of the effects of energetic particles on processes in the entire atmosphere.

  11. Lightning as a space-weather hazard: UK thunderstorm activity modulated by the passage of the heliospheric current sheet

    M. J. Owens, C. J. Scott, A. J. Bennett,
    S. R. Thomas, M. Lockwood, R. G. Harrison, M. M. Lam
    19 November 2015

    ….Thus, the CIR effect on lightning is either the result of compression/amplification of the HMF (and its subsequent interaction with the terrestrial system) or that energetic particle preconditioning of the Earth system prior to the HMF polarity change is central to solar wind lightning coupling mechanism.
    1 Introduction

    Lightning is of interest to a wide range of disciplines from atmospheric chemistry to studies of aviation hazards and forest fire management. It has long been speculated that there exists a (causal) link between solar activity and terrestrial thunderstorm activity [Brooks, 1934; Stringfellow, 1974]. The prime focus has been on long-term trends (months to years), in particular a covariance between lightning rates and the solar cycle, although both in-phase [Stringfellow, 1974; Schlegel et al., 2001] and antiphase [Chronis, 2009; Pinto Neto et al., 2013] relations have been reported, which may be a result of lightning in different geographic locations responding differently to solar variations or other solar modulations of the climate system. Lightning rates have traditionally been compared with sunspot number or galactic cosmic ray (GCR) intensity at Earth….

    • Carla, A good Earth or Ground is the most important part of the global electric circuit it’s the part where we live. Lightning is one way that the positive “+” atmosphere and negative “-” Earth interact in regard to balancing the global electric circuit. I put a few bits together in a earlier post about the global electric circuit but it hasn’t been released from moderation yet. It’s taking up to a couple of day’s before it gets posted , by then the conversation has ended. I don’t understand why it takes so long, maybe it’s to sensitive a topic for someone. It would be nice if the moderator would give me a heads up , so I don’t wast my time exposing the truth.

  12. See Molinari, J., N. Demetriades, R. Holle and D. Vollaro. 2006. Applications of long-range lightning data to hurricane formation and intensification. Preprint. 2nd Conf. Meteor. Appl. Lightning-Data:3.5
    I saw massive lightning offshore (almost horizon to horizon) prior to Hurricane Celia (1970), coalescing, then strongly striking the central Texas coast. Paper refers to Claudette (2003), which while much more benign, may have been similar.

Comments are closed.