Meteorology IV

METEOROLOGY –WEATHER HAZARDS 

T H U N D E R S T O R M S 

Formation when 1) Source of lift (heating, fast-moving front), 2) unstable air (nonstandard lapse rate), 3) high moisture content (temp/dew point close)

Florida experiences“air mass thunderstorms”with Sea-Land breezes and associated instability, but can turn to“Severe”with winds at or greater than 50 KTS, hail ¾inches or greater, and tornadoes.

Single-cell, multi-cell andsuper-cell thunderstorms are common here. Frontal passage sometimes producesSQUALL LINES up to 300 miles in front.

Updrafts and Downdrafts can exceed 3,000 fpm

*Life cycle of a thunderstorm.

Some storms occur at random in unstable air, last for only an hour or two, and produce only moderate wind gusts and rainfall. These are known as air mass thunderstormsand are generally a result of surface heating. Steadystate thunderstormsare associated with weather systems. Fronts, converging winds, and troughs aloft force upward motion spawning these storms which often form into squalllines. In the mature stage, updrafts become stronger and last much longer than in air mass storms, hence thename steady state.

*Movement and turbulence of a maturing thunderstorm

METEOROLOGY –WEATHER HAZARDS Stages of Thunderstorms

LIGHTNING

ALL TYPES OF LIGHTNING:  JUST KNOW THAT AIRPLANES & LIGHTNING DON’T MIX WELL

Average Output: 1 Terawatt/30,000 Amps for about 30 Microseconds@ 36,000 degrees F.(3 times the Sun’s surface temperature).

Volcanic (Chili –May 2009)

Upper-Atmospheric Lightning

Sprites are large scale electrical discharges which occur high above cumulonimbus, They often occur in clusters, lying 50miles to 90miles. 

Blue jets differ from sprites in that they project from the top of the cumulonimbus above a thunderstorm, typically in a narrow cone, to the lowest levels of the ionosphere 25 to 30 mile in altitude. 

Giant jets are located above a thunderstorm over the ocean, and lasted under a second. Lightning was initially observed traveling up at around 50,000 m/s in a similar way to a typical blue jet, but then divided in two and speed at 250,000 m/s to the ionosphere, where they spread out in a bright burst of light. 

Elves (Emissions of Light and Very Low Frequency Perturbations from Electromagnetic Pulse Sources) often appear as a dim, flattened, expanding glow around 400 km (250 miles) in diameter that lasts for, typically, just one millisecond . 

Upper-Atmospheric Transient Luminous Event –Aurora Borealis

You can learn by yourself with the material below:
- Pilot's Handbook of Aeronautical Knowledge [PHAK]
- Online Meteorology Guide

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