Thunderstorms – METAR TS with a – for light and for heavy
Out of all of the specific weather hazards thunderstorms are perhaps the greatest threat to pilots because they can be your one-stop-shop for danger. When discussing thunderstorms lightening and turbulence are not your only enemy. They are able to generate anything from huge hail to tornadoes and microbursts all of which may be lethal.
Not all thunderstorms exude these occasions three situations need to be present- medium to higher moisture content any quantity of air instability and some lifting motion. The lifting motion could be caused by modifications in terrain elevation frontal alterations or temperature raises and decreases.
You can find two varieties of thunderstorms – airmass thunderstorms and extreme thunderstorms. Airmass thunderstorms are one of the most frequent. Theyve a tendency to pop up on summer afternoons or for the duration of coastal evenings is usually short in length and are normally scattered. Extreme thunderstorms as are additional violent and produce wind gusts starting at 50 knots or higher create hail inches in diameter or bigger and may also turn out tornadoes.
Thunderstorms have three stages or perhaps a daily life cycle – the cumulus stage mature stage and dissipating phase. Cheap flights last minute These three stages are noticed in each and every single thunderstorm formation. The cumulus stage has constant updrafts as good as 3000 ft per minute Abbott Kailey 2004. The storm matures when the cloud becomes too dense to be supported by the drafts in the previous stage.
When you picture a fully-formed thunderstorm cloud you are thinking of this probably the most violent stage with the storm. One side from the storm still has warm updrafts while the leading edge on the storm has cool precipitation. Also at the leading edge are strong winds. Inside the dissipating stage the cloud ceiling rises at least 10000 ft and the updraft is found exclusively within the cloud. The entire cloud now sheds rain and accompanying down drafts.
A thunderstorm can existing itself as single-cell super-cell or multi-cell. Weve all noticed pictures of your updraft of a thunderstorm. They start out rather flatly at a low altitude and vertical updrafts cause the storm to billow up beyond 30000 ft. A single-cell thunderstorm isnt anything to sniff at and lasts under an hour. Super-cell thunderstorms are quite severe and can last up to two hours.
Multi-cell storms are condensed groups of thunderstorms in different levels from the everyday life cycle. This grouping causes the storms to interact with each and every other and therefore last a lot longer. Sometimes these groupings cause whats known as squall lines. One misconception is that quall lines are always equated having a front. While this is usually the case these squalls can happen anywhere. When they may be indeed frontal thunderstorms they develop 50 to 300 miles in front of a fast-moving cold front. Abbott Kailey 2004
Thunderstorm-specific hazards-
Lightening – Reports submitted by PIREPs and Weather offices with live lightening trackers.
Lightening almost goes without saying. Lightening may be categorized as in-cloud cloud-to-cloud cloud to ground and between cloud and clear air although rare. No matter which type lightnings voltage is about 300000 volts per foot and is an astounding 50000F. Abbott Kailey 2004 This heat causes the surrounding air to expand and a corresponding shock wave that we know as thunder.
Lightening strikes can cause external damage to the aircraft but rarely causes catastrophic damage to airplane or crew. It can temporarily blind pilots at night and it can effect the aircrafts navigational equipment.
Turbulence – METAR not applicable. Reports are submitted as a PIREP.
While turbulence isnt exclusive to thunderstorms it is an expected and predictable phenomenon unlike unexpected clear-air turbulence. The Thunderstorm-related turbulence occurs right where the updrafts and down drafts combine in. Anyone who as flown through turbulence can relate to the jerky up and down sensation can relate to this.
Turbulence nicknamed chop might be light moderate or serious. When reporting turbulence to air traffic control from the air you will discover no set rules in determining the severity. Pilots leave it up to popular sense and previous experience when reporting light or moderate chop although experts would say moderate chop is often felt when the updraftdowndraft gusts are around 30 knots. Severe isnt typically experience by pilots without their Instrument Flight Rating unless they experience clear-air turbulence as they stay away from storms and clouds in general. IFR flights are normally channeled away from reported extreme turbulence by air traffic control.
Microburst – no METAR code reported by PIREPS and is often put in the remarks section of speci sic climate reports
Microbursts are perhaps 1 of essentially the most feared weather occurrences out there. They may be low in altitude and can occur in an area of 1 nautical mile or less horizontally and 1000 feet vertically Abbott Kailey 2004. Aircraft landing or taking off or low-flying aircraft are most likely to run into this phenomenon.
Microbursts are lethal due to the fact the winds can increase upwards of 100 knots but the real hazard lies within the downbursts of up to 6000 ft per moment. Many commercial flights over the years have crashed due to microbursts such as Delta Air Lines Flight 191 in 1985 and USAir Flight 1016 in 1994 – both happened while on approach to their respective runways.
Hail – METAR GR Small hail is GS along with snow pellets
Hail is brought on by rain drops being picked up by the updrafts of a thunderstorm which are then frozen at higher altitudes. Once they become too major to be supported by the updrafts the chunks of hail anywhere from the size of a raindrop to a baseball or larger depending on how many friends it gathered on the way up fall to the ground at a large velocity over 100 MPH. Three-quarters of an inch or extra is all the girth thats needed to cause structural damage to an airplane Abbott Kailey 2004.
Tornadoes – METAR FC for funnel clouds tornadoes or water spouts
Tornadoes or funnel clouds might be predicted and spotted by local climate offices using Doppler Radar. The weather information is then sent to local air traffic control facilities and ARTCCs. The controllers will then do their best to control aircraft away from these violent storms. Low-flying unaware VFR aircraft would be in most danger as tornadoes are formed at cloud bases and VFR flights usually are not always speaking to a tower or arrivalapproach facility though pilots without an IFR rating wouldnt be allowed in areas with weather bad enough anyway. Tornadoes are caused by the rotation brought on by thunderstorms. Funnel clouds are called tornadoes once they touch the ground. The wind speeds within a tornado can exceed 200 knots.
Serious weather could be avoided by obtaining a thorough and current climate report from an airports weather office 1-800-WX-BRIEF or an AFSS before taking off. Climate problems are updated at least every single hour on the airport ATIS. Air traffic controllers will advise all IFR flights of any alterations as theyre reported.
Source-
Mike Abbott Liz Kailey et al. 2004. Colorado- Jeppesen-Sanderson. Cheap flights last minute