Cloudspotters who find themselves in the path of a ferocious ‘multicell’ or ‘supercell’ storm system, may have the unsettling experience of looking up into a ‘whale’s mouth’. This is the name storm chasers give to the huge, dark void that can appear in the region below and ahead of the storm.

The whale’s mouth forms as a result of very strong ‘downdraughts’ of cool air, which are associated with such severe storm systems. On reaching the ground, this cool air spreads out like a tide beneath the advancing storm. As it does so, it lifts the warmer, lighter air at ground-level, which then cools enough for its moisture to condense into cloud. This cloud is the roof of the whale’s gaping mouth, while the blubbery-looking rim along the front of the spreading air is the whale’s top lip*.

The storms that give rise to whales’ mouths are particularly fierce. Cloudspotters should avoid staring for too long into the jaws of these mighty beasts, or they may just end up as dinner.

…

*N.B. This is officially known as a ‘shelf cloud’,
not a ‘top-lip-of-a-whale cloud’

Current Cloud of the Month:
‘Asperatus’ (June 09)

Previous Clouds of the Month:
Clouds at Night (May 09)
Sundogs (April 09)
Diamond Dust (March 09)
Cloud Streets (February 09)
Crepuscular Rays (Jan 09)
Valley Fog (December 08)
Cloud Shadows (November 08)
Contrails (October 08)
Mamma (September 08)
Kármán Vortex (August 08)
The Summertime Halo (July 08)
The Nor’west Arch (June 08)
Microbursts (May 08)
Irridescent Clouds (April 08)
Northern Lights – Aurora Borealis (March 08)
Ice halos (February 08)
Lightning (January 08)
Roll Cloud (December 07)
Banner Cloud (November 07)
Stratocumulus (October 07)
The Unclassified Cloud (September 07)
Alexander’s Dark Band (August 07)
Fumulus Snail (July 07)
Distrail (June 07)
Altocumulus undulatus (May 07)
Cumulonimbus capillatus (April 07)
Lacunosus (March 07)
Horseshoe Vortex Cloud (February 07)
Jet-Stream Cirrus (Janurary 07)
Altostratus/Altocumulus/Altowhateveritis (December 06)
Anti-Crepuscular Rays (November 06)
Stratocumulus (October 06)
Altocumulus (September ’06)
The Kelvin-Helmholtz Wave Cloud (August ’06)
The ‘Brocken Spectre’ (July ’06)
‘Whale’s Mouth’ (June ’06)
Noctilucent (May ’06)
Cirrus (April ’06)
Cap Cloud (March ’06)
Fallstreak Holes (February ’06)
Nacreous (January ’06)
Cirrostratus (December ’05)
Tuba (November ’05)
Virga (October ’05)
Cirrocumulus (September ’05)
Altostratus (August ’05)
Cumulus (July ’05)
Mamma (June ’05)
Pileus (May ’05)
Lenticularis (April ’05)


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go to our Photograph Submissions page.

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