Spanish for “straight,” a derecho is a wide, straight-¬line wind storm with speeds over 58 mph that generates a continuous series of severe thunderstorms. Wind speeds in a derecho typically increase after the passing of its associated front and approach 100 mph. The strongest recorded have peaked around 130 mph. Low¬-level warm air advection, rich
Read MoreHail is best detected by radar, which shoots radiation in all directions and measures the density of the beams that the nearby environment reflects back. Areas of higher reflectivity indicate more atmospheric content, which indicates the storm cell observed is likely close to maturation. This means it has a speedy, tall updraft and copious ambient
Read MoreWhat’s in the past is in the past, so why focus on yesterday’s weather? Understanding what the weather was yesterday, last week, or even farther back in time can be immensely useful for a variety of purposes. Insurance companies solving disputes, attorneys using scientific testimony in court, airlines and government rely on forensic meteorologists to
Read MoreHail originates as tiny cloud droplets with diameters of 0.02 mm. After large masses of these droplets are sucked into updrafts, they elevate to heights that are much colder than the surface. Their rapid transport and the lack of ice nuclei in their paths cause them to cool below 0°C without freezing (supercool.) Soon, additional
Read MoreBefore tornadoes, there exist mesocyclones: giant, rotating columns of low-pressure air that sink below the height of their surrounding cloud basins. Sometimes subsidiary vortices called tornadoes spawn under them. The already swiftly-moving air circulating above is restrained into a smaller diameter and, due to the conservation of angular momentum, wind speed is increased. If the
Read MoreNature’s deadliest surprises, tornadoes can spontaneously develop in supercell thunderstorms, along squall lines, near the ends of bow echoes, and within hurricanes after they’ve moved ashore. They may generate the strongest winds of any atmospheric phenomenon: over 200 mph. Annually, they kill dozens and injure hundreds. Typically they are responsible for around $100 million in
Read MoreFrontal squall lines form just ahead of surface cold fronts and dry lines, and also ahead of upper-level fronts. If the necessary conditions exist, they may stretch to hundreds of miles in length. They may bring tornadoes and hail but they’re more commonly associated with strong straight-line winds. If the flow along a squall line
Read MoreHook echoes are meteorological phenomena named after their shapes. They’re created when vertical wind shear causes warm, moist air, sucked in by the unstable movements of a supercell thunderstorm, to mix with a different incoming channel of drier, cooler air. The shape they assume resembles a hook because the two streams of air aren’t mixing
Read MoreClouds at temperatures between 0 and -40C contain a mixture of ice crystals and super-cooled water. At colder temperatures, ice crystals prevail. Super-cooled water is responsible for the threat of aircraft structural icing, but at lower temperatures, this threat decreases. Because of the lack of super-cooled water, icing, other that of light intensity, is unlikely
Read MoreA microburst is a strong downward oriented wind usually associated with thunderstorms. These winds usually form within a cumulonimbus cloud that is mature and are often associated with heavy rain and perhaps along with hail. These winds can cause major issues such as crashes with airplanes during take-off and or landing. In an attempt to
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