NTR: derecho

[dr-shorthair]

Superclass: atmospheric storm

Ref: https://en.wikipedia.org/wiki/Derecho

[kaiiam]

The wiki Derecho states a derecho

is a widespread, long-lived, straight-line wind storm that is associated with a fast-moving group of severe thunderstorms known as a mesoscale convective system.

straight-line wind according to it's wiki are simply "very strong winds". According to our definition of storm processes have to be strongly perturbed by external forcings. Hence straight-line wind could perhaps be subclass to a new term windstorm (which would be subclass to atmospheric storm).

I proposed the following hierarchy of terms:

atmospheric storm
   windstorm
      straight-line wind
         derecho

windstorm db_x_ref

An atmospheric storm during which intense atmospheric winds occur.

Subclass of: 'atmospheric storm'

'has part' some 'atmospheric wind'

straight-line wind dbxref1 dbxref2

A fast-moving windstorm which is moves in constant direction, lacking a rotational pattern.

Subclass of: windstorm

maybe narrow synonyms: plough winds and thundergusts (only the wiki page seems to have these)

derecho dbxref

A widespread, long-lived, straight-line wind storm which is associated with a fast-moving group of severe thunderstorms.

Subclass of: straight-line wind

'has part' some 'thunderstorm'

[pbuttigieg]

Good drafting @kaiiam

We should think about cross-axiomatising with PATO's "linear' quality, but must note that processes can only (strictly speaking) have rate qualities. That is to say, the wind isn't linear, but the aeroform that it creates is.

Note I say think about - we shouldn't slow down these requests with these axioms, but table them for later development.

[kaiiam]

I'll throw in the following editors note for the new straight-line wind class:

Add cross-axiomatization with PATO's 'linear' quality http://purl.obolibrary.org/obo/PATO_0001199. Although processes can only have rate qualities, we want to capture the linear quality of the aeroform created by straight-line winds.

[kaiiam]

cross reference to PR #851

[pbuttigieg]

I'm getting conflicting definitions of derecho. Some use it to refer to the winds, others to the storm system that produces such winds. Compare: https://en.wikipedia.org/wiki/Derecho https://www.merriam-webster.com/dictionary/derecho

Note, however, that the Wikipedia article is inconsistent, also noting:

A common definition is a thunderstorm complex that produces a damaging wind swath of at least 400 km (250 miles),[9] featuring a concentrated area of convectively-induced wind gusts exceeding 30 m/s (90 km/h; 50 kn; 60 mph).[1] According to the National Weather Service (NWS) criterion, a derecho is classified as a band of storms that have winds of at least 30 m/s (90 km/h; 50 kn; 60 mph) along the entire span of the storm front, maintained over a time span of at least six hours. Some studies add a requirement that no more than two or three hours separate any two successive wind reports.[10] A more recent, more physically-based definition of "derecho" proposes that the term be reserved for use with convective systems that not only contain unique radar-observed features such as bow echoes and mesovortices, but also for events that produce damage swaths at least 100 km (60 miles) wide and 650 km (400 miles) long.[2]

Thus I'm going with the derecho as a storm system that produces downbursts unless there are divergent views.

[pbuttigieg]

Folding this into #824, along with #849 and others.

[dr-shorthair]

Will report back on the UNDRR definition when it has been agreed ;-)

[pbuttigieg]

seems there's quite a bit of fuzziness in the meteorological definitions, which is to be expected when trying to delineate air masses. There's an incoming tropical storm over here, on the fringe of a typhoon, which is motivating me for these NTRs 🌪

[kaiiam]

Just to be clear derecho still remains to be added. I had made pull request 851 which included windstorm, straight-line wind and derecho, however @pbuttigieg separately added wind storm and straight-line wind in #824, but not derecho. Hence I'll delete pull request 851, but we still need to add derecho when we have a better definition.

The previous definition was:

A widespread, long-lived, straight-line wind storm which is associated with a fast-moving group of severe thunderstorms.

with axioms:

subclass of straight-line wind

has part thunderstorm

@dr-shorthair do you have an update on a definition and or axioms for derecho?

[dr-shorthair]

No - sorry - it was just an item on a list for me, coming from a community who wanted it included.