![]() ![]() When lightning strikes it sends out pulses of radio waves and these can be used to detect lighting strokes. The Met Office ATDnet system detects these pulses at a frequency known as VLF (Very Low Frequency) - much lower frequency than normal radio waves. These include intense rain and tornadoes. Detecting lightningīeing able to detect the location of thunderstorms is of great importance as it is not only the lightning strike that is dangerous, but many other factors linked to thunderstorms. When positive lighting strikes it is forced to go around the negatively charged base of the cloud, this generally results in a more powerful lighting strike which shoots out sideways and sometimes can travel a mile more away from the storm cloud before connecting with the ground. The nature of this type of lightning strike is where get the term 'a bolt from the blue'. Most lightning strikes originate from the negative part of a cloud, however occasionally a strike can come from the positively charged top part - this is called 'positive lightning'. The term lightning 'strike' refers to cloud-to-ground lightning, where lightning 'strikes' the ground. A lightning flash is what you can see, but this is often made up of several individual lighting strokes which are pulses of current which occur separately if though only hundredths of a second apart. Lightning flashes and lightning strikesĪlthough often assumed to be the same thing, there is a key distinction between lightning flashes and lighting strikes. As the attraction between the cloud and the ground grows stronger, electrons shoot down from the cloud cutting through the air at around 270,000 miles per hour. This leaves the ground and the objects on it with a positive charge. The path they make in doing so forms the channel we see during a flash of lightning.Īs negative charge builds at the base of the cloud, the electrons near the ground's surface are repelled. If the attraction is strong enough, the electrons will rapidly move towards the positive atoms. As well as being attracted to the positive charge in the top of the cloud, the surplus of electrons in the cloud base are attracted to positive charge in other clouds and on the ground. ![]() ![]() ![]() The hail continues to fall through in the lower part of the cloud, giving it a negative charge. The updraughts continue to carry the ice particles upwards, giving the top of the cloud a positive charge. During these collisions, electrons are transferred to the hail giving the hail a negative charge, while the ice particles that have lost electrons gain a positive charge. Some of the hail that forms becomes too heavy to be propelled by the updraughts and so begin to fall back through the cloud, bumping into smaller ice particles as they do so. Some of the pieces of ice grow into hail, but others remain very small. This page will be updated to a more robust version including PIREPs by the end of April.As tiny water droplets form inside a storm cloud, they are propelled towards the top of the cloud by strong internal winds (updraughts) where they turn to ice. The NWS Radar page and NWS Satellite page also are available. The URL should auto-update with the current settings, allowing for an easy bookmark/favorite. Īdditional URL parameters include lt (center latitude), ln (center longitude), zm (zoom level, 0-12), nolabel (removes flight category icon ID labels), hidemenu (hides the menu options on the lower left), wide (thicken US state boundaries), county (include US counties and other political boundaries based on zoom level), hidefir (hide FIR boundary), zseareas (add the ZSE ARTCC areas), and start (UTC start date/time, YYYYMMDDhhmm format, AWC data goes back up to 2 days, GLM data up to 5 hours). To expand the radar map, keeping the menus/options above and legend below, click ⟺ (include "&invert" in the URL to reverse the background/text colors). To toggle the lower-left menu visible/hidden, click the ≪ or ≫ button. Left-clicking on the "Speed" area will slow the loop and right-clicking will accelerate the loop, ranging from 0.05 to 5 second interval. When both the flight category and weather are displayed, the flight category icon will be on the inside and the partially-transparent weather color on the outside.Ĭlicking on the map will start/stop the loop. Also, GeoColor images may occasionally miss a frame or two. On the GeoColor satellite images (GOES-West/East cutoff at -114°) the pale bule areas are nighttime areas of lower clouds. The radar, lightning, visible satellite, IR satellite, GeoColor satellite, SIGMETs/CWAs, and flight categories/weather can be toggled on/off. The above loop uses radar and visible/IR satellite data obtained from Aviation Weather Center (AWC), GeoColor satellite data from NOAA NESDIS-STAR, lightning (GLM) data from NOAA nowCOAST, and observations (for flight category and weather) from MesoWest. ![]()
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