Tropospheric cloud types with Latin etymologies where applicable List of cloud types

1 tropospheric cloud types latin etymologies applicable

1.1 wmo genera
1.2 wmo species
1.3 wmo varieties
1.4 wmo supplementary features
1.5 genitus mother clouds
1.6 other genitus clouds
1.7 mutatus mother clouds
1.8 informal terms accepted wmo classification latin nomentclature
1.9 wmo , informal terms related free-convective cloud types , storms

tropospheric cloud types latin etymologies applicable

cloud types sorted in alphabetical order except noted.

wmo genera

altocumulus (altus , cumulus) - latin high heap : applied mid-level stratocumuliform.
altostratus (altus , stratus) - high sheet : applied mid-level stratiform.
cirrocumulus (cirrus , cumulus) - hair-like heap : applied high-level stratocumuliform.
cirrostratus (cirrus , stratus) - hair-like sheet : applied high-level stratiform.
cirrus - hair-like : applied high-level cirriform.
cumulonimbus - (cumulus , nimbus) precipitation-bearing heap : applied vertical/multi-level cumulonimbiform.
cumulus - heap : applied low-level , vertical/multi-level cumuliform.
nimbostratus (nimbus , stratus) - precipitation-bearing sheet : applied multi-level stratiform vertical extent produces precipitation of significant intensity.
stratocumulus (stratus , cumulus) - sheet-like heap : applied low-level stratocumuliform.
stratus - sheet : applied low-level shallow stratiform.

wmo species

castellanus (cas) – latin castle-like : applies stratocumuliform (sc cas, ac cas, cc cas) , dense cirriform (ci cas) series of turret shapes – indicates air mass instability.
congestus (con) – latin congested : applies cumuliform (cu con/tcu) great vertical development , heaped cauliflower shapes – indicates considerable airmass instability , strong upcurrents.
fibratus (fib) – fibrous : cirriform (ci fib) or high stratiform (cs fib) in form of filaments, can straight or curved.
floccus (flo) – tufted : applies stratocumuliform (sc flo, ac flo, cc flo) , high cirriform (ci flo); indicates mid or high-level instability.
fractus (fra) - broken : low stratiform (st fra) or cumuliform (cu fra) irregular shredded appearance – forms in precipitation and/or gusty winds.
humilis (hum) – small : applies cumuliform (cu hum) little vertical extent; indicates relatively slight airmass instability.
lenticularis (len) lens–like : stratocumuliform (sc len, ac len, cc len) having lens-like appearance – formed standing waves of wind passing on mountains or hills.
mediocris (med) – medium-size : cumuliform (cu med) moderate vertical extent; indicates moderate instability , upcurrents.
nebulosus (neb) – nebulous : indistinct low , high stratiform (st neb, cs neb) without features; indicates light wind if , stable air mass.
spissatus (spi) – dense : thick cirriform (ci spi) grey appearance; indicates upward movement of air in upper troposphere.
stratiformis (str) – sheet-like : horizontal cloud sheet of flattened stratocumuliform (sc str, ac str, cc str); indicates slight airmass instability.
uncinus (unc) – hook-like : cirriform (ci unc) hook shape @ top; indicates nearby backside of weather system.
volutus (vol) - rolled : elongated, low or mid-level, tube shaped, stratocumuliform (sc vol, ac vol).

the division of genus types species shown in following table. species sorted left right in approximate ascending order of instability or vertical extent. genus types arranged top bottom in same ascending order of instability within each étage. (1)=stratiform types, (2)=cirriform types, (3)=stratocumuliform types, (4)=cumuliform types, (5)=cumulonimbiform types.

vert=vertical or multi-level, mv=moderate or deep vertical, tv=towering vertical.

wmo varieties

opacity-based

opacus - latin opaque : thick sheet of stratiform or stratocumuliform cloud.
perlucidus - semi-transparent : sheet of stratocumuliform cloud small spaces between elements.
translucidus - translucent : thin translucent patch or sheet of stratiform or stratocumuliform.

pattern-based

duplicatus - latin double : closely spaced partly merged layers of cloud in 1 of several possible forms.
intortus - twisted : curved , tangled cirriform.
lacunosus - full of holes : thin stratocumuliform cloud distinguished holes , ragged edges.
radiatus - radial : clouds in 1 of several possible forms arranged in parallel lines appear converge @ central point near horizon.
undulatus - wavy : stratiform or stratocumuliform cloud displaying undulating pattern.
vertebratus - in form of back-bone : cirriform arranged back-bone of vertebrate.

the following table shows cloud varieties arranged across top of chart left right in approximate descending order of frequency of appearance. genus types associated each variety sorted top bottom in left column in approximate descending order of average overall altitude range. applicable, genera , varieties cross-classified show species associated each combination of genus , variety. exceptions include altostratus has varieties no species, towering cumulus , cumulonimbus have species no varieties, , nimbostratus has no species or varieties.

wmo supplementary features

a translucent wave cloud -altocumulus lenticularis

precipitation-based supplementary features

praecipitatio - latin falling : cloud precipitation reaches ground.
virga - twig or branch : cloud precipitation evaporates before reaching ground.

cloud-based supplementary features

arcus - latin arch or bow : feature attached cumulus, thick ragged edges.
asperitus - roughness : highly disturbed , chaotic wave feature seen undulatus cloud @ altitude in troposphere.
cavum - hole : supercooled altocumulus or cirrocumulus distinguished hole ragged edges , virga or wisps of cirrus.
cauda: - tail : tail cloud extends horizontally away murus cloud , result of air feeding storm.
fluctus: crested wave-like clouds formed wind-shear instability may occur @ altitude in troposphere undulatus cloud.
incus - anvil : top part of mature cumulonimbus cloud; anvil-shaped feature.


mammatus on squaw valley



mammatus; wmo term mamma: - breast : feature in form of round pouches on under-surface of cloud.
murus: - wall : cumulonimbus wall cloud lowering rotating base can portend tornadoes.
tuba: - funnel or tube : feature in form of column hanging bottom of cumulus or cumulonimbus.

accessory clouds

pannus - latin shredded cloth : ragged or shredded accessory cloud forms in precipitation below main cloud.
pileus - capped : hood-shaped accessory cloud.
velum - ship s sail : accessory cloud in form of sail.

the supplementary features associated particular genera follows. sorted left right in approximate decreasing order of frequency of occurrence each of 3 categories. genus types (including cumulus sub-types) arranged top bottom in approximate descending order of average overall altitude range.

genitus mother clouds

altocumulogenitus - formed partial transformation of altocumulus mother cloud.
altostratogenitus - formed partial transformation of altostratus.
cirrogenitus - partial transformation of cirrus.
cirrocumulogenitus - partial transformation of cirrocumulus.
cirrostratogenitus - partial transformation of cirrostratus.
cumulogenitus – spreading out or partial transformation of cumulus.
cumulonimbogenitus – spreading out or partial transformation of cumulonimbus.
nimbostratogenitus - partial transformation of nimbostratus.
stratogenitus - partial transformation of stratus.
stratocumulogenitus - partial transformation of stratocumulus.

other genitus clouds

cataractagenitus (cataracta-/pertaining river cataract) - formed mist @ waterfall.
flammagenitus (flamma-/pertaining fire) - formed convection associated large wildfires.
homogenitus (homo-/pertaining humans) - formed result of human activities, particularly aircraft @ high altitudes , heat-generating industrial activities @ surface level. if homogenitus cloud of 1 genus changes genus type, termed homomutatus cloud.
silvagenitus (silva-/pertaining trees or forests) - formed low-level condensation of water vapor released vegetation, forest canopies.

mutatus mother clouds

nomenclature works same way genitus mother clouds except mutatus suffix indicate complete rather partial transformation of original cloud type. e.g. altocumulomutatus - formed complete transformation of altocumulus mother cloud.

the possible combinations of genera , mother clouds can seen in table. genitus , mutatus clouds each sorted left right in alphabetical order. genus types (including cumulus sub-types) arranged top bottom in left column in approximate descending order of average overall altitude range.

informal terms accepted wmo classification latin nomentclature

aviaticus cloud - persistent condensation trails (contrails) formed ice crystals originating water vapor emitted aircraft engines. may resemble cirrus, cirrocumulus, or cirrostratus depending on atmospheric stability , wind shear. accepted wmo genitus cloud homogenitus (man-made).
fallstreak hole – supercooled altocumulus or cirrocumulus distinguished hole ragged edges , virga or wisps of cirrus. accepted wmo supplementary feature named cavum (hole).
kelvin–helmholtz cloud - crested wave-like clouds formed wind-shear instability may occur @ altitude in troposphere. accepted wmo supplementary feature latin name fluctus.
pyrocumulus , pyrocumulonimbus - cumulus , cumulonimbus clouds formed generated ground heat; including forest fires, volcanic eruptions , low level nuclear detonation. accepted wmo genitus cloud latin name flammagenitus, or homogenitus in case of small cumulus formed contained human activity.


roll cloud on wisconsin



roll cloud – elongated, low-level, tube shaped, horizontal formation not associated parent cloud. accepted wmo stratocumulus or altocumulus species latin name volutus.

wmo , informal terms related free-convective cloud types , storms

accessory cloud (wmo supplementary feature) – secondary cloud associated separate main cloud.
anvil (wmo supplementary feature incus) – anvil top of cumulonimbus cloud.
anvil dome (wmo supplementary feature incus) – overshooting top on cb present on supercell.
anvil rollover – (slang) circular protrusion attached underside of anvil.
arcus cloud (wmo supplementary feature) – arch or bow shape, attached cumulus, thick ragged edges.
backsheared anvil – (slang) anvil spreads upwind, indicative of extreme weather.
clear slot or dry slot (informal term) – evaporation of clouds rear flank downdraft descends , dries out cloud , occludes around mesocyclone.
cloud tags (wmo species fractus) – ragged detached portions of cloud.
collar cloud (wmo velum accessory cloud) – ring shape surrounding upper part of wall cloud.
condensation funnel (wmo supplementary feature tuba) – cloud of funnel cloud aloft or tornado.
altocumulus castellanus (wmo genus , species) – castle crenellation-shaped altocumulus clouds.
cumulus (wmo genus) – heaped clouds.
cumulus castellanus – (informal variation of wmo genus , species cumulus congestus) cumulus tops shaped castle crenellations.
cumulus congestus (wmo genus , species) – considerable vertical development , heaped cauliflower shapes.
cumulus fractus (wmo genus , species) – ragged detached portions of cumulus cloud.
cumulus humilis (wmo genus , species) – small, low, flattened cumulus, development.
cumulus mediocris (wmo genus , species) – medium-sized cumulus bulges @ top.
cumulus pileus (wmo genus , accessory cloud) – capped, hood-shaped cumulus cloud.
cumulus praecipitatio (wmo genus , supplementary feature) – cumulus precipitation reaches ground.
cumulus radiatus (wmo genus , variety) – cumulus arranged in parallel lines appear converge near horizon.
cumulus tuba (wmo genus , supplementary feature) – column hanging bottom of cumulus.
cumulonimbus (wmo genus) – heaped towering rain-bearing clouds stretch upper levels of troposphere.
cumulonimbus calvus (wmo genus , species) – cumulonimbus round tops cumulus congestus.
cumulonimbus capillatus (wmo genus , species) – cb cirriform top.
cumulonimbus incus (wmo genus , supplementary feature) – cb capillatus anvil top.
cumulonimbus mamma (wmo genus , supplementary feature) – cb pouch-like protrusions hang under anvil or cloud base.
cumulonimbus pannus (wmo genus , accessory cloud) – shredded sections attached main cb cloud.
cumulonimbus pileus (wmo genus , accessory cloud) – capped, hood-shaped cloud above cumulonimbus cloud.
cumulonimbus praecipitatio (wmo genus , supplementary feature) – cb precipitation reaches ground.
cumulonimbus tuba (wmo genus , supplementary feature) – column hanging bottom of cumulonimbus.
debris cloud (informal term) – rotating cloud of debris found @ base of tornado.
funnel cloud (wmo supplementary feature tuba) – rotating funnel of cloud hanging under cb, not making contact ground.
hail fog (informal term) – shallow surface layer of fog forms in vicinity of deep hail accumulation, can dense.
hot tower (informal term) - tropical cumulonimbus cloud penetrates tropopause.
inflow band (informal term) – laminar band marking inflow cb, can occur @ lower or mid levels of cloud.
inverted cumulus (informal variation of wmo supplementary feature mamma) – cumulus has transferred momentum exceptionally intense cb tower , convectively growing on underside of anvil.
knuckles (informal variation of wmo supplementary feature mamma) – lumpy protrusion hangs edge or underside of anvil.
pyrocumulus , pyrocumulonimbus– intense ground-heat cloud proposed wmo classification (see above).
rope – (slang) narrow, twisted funnel type cloud seen after tornado dissipates.
rope cloud (informal term) – narrow, long, elongated lines of cumulus cloud formation develop @ leading edge of advancing cold front or weather fronts visible in satellite imagery.
scud cloud (informal term wmo species fractus) – ragged detached portions of cloud form in precipitation.
shelf cloud (informal term wmo supplementary feature arcus) – wedge-shaped cloud attached underside of cb.
stratus fractus (wmo genus , species) – ragged detached portions of stratus cloud form in precipitation (see scud cloud).
striations (informal term wmo accessory cloud velum) – groove or band of clouds encircling updraft tower, indicative of rotation.
tail cloud (informal term) – area of condensation consisting of laminar band , cloud tags extending wall cloud towards precipitation core.
towering cumulus (tcu) -aviation term wmo genus , species cumulus congestus, large cumulus cloud great vertical development, cauliflower-like appearance, lacking characteristic anvil of cb.
wall cloud (informal term) – distinctive large lowering of rain-free base of cb, rotating.




^ task team on revision of international cloud atlas (2013). final report (pdf). world meteorological organization. retrieved 2014-10-06. 
^ http://cimss.ssec.wisc.edu/goes/blog/archives/555