arched squall

American  

[ahrcht skwawl] / ˈɑrtʃt ˈskwɔl /

noun

Meteorology.

1. a potentially violent squall in which storm clouds appear as a well-developed arch rising above the horizon.

   The afternoon’s calm at sea had been ushered in by a treacherous arched squall, which had us scrambling to our sails in a hurry.

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Etymology

Origin of arched squall

First recorded in 1810–15