Cloud Street

güttsfükk · #1 02-26-2009, 09:48 PM

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Cloud streets are rows of cumulus or cumulus-type clouds aligned parallel to the low-level wind.

The most favorable conditions for their formation occur when the lowermost layer of air is unstable, but is capped by an inversion-by a stable layer of air. This often occurs when upper air is subsiding, such as under anticyclonic conditions, and is also frequently found when radiation fog has formed overnight. Convection occurs below the inversion, with air rising in thermals below the clouds and sinking in the air between the streets. Cloud streets provide glider pilots with lines of rising air, enabling them to fly straight for long distances while still climbing.

Cloud streets are usually more or less straight, but rarely cloud streets assume paisley patterns when the wind driving the clouds encounters an obstacle. Those cloud formations are known as von Kármán vortex streets. Although conventional cloud streets are clearly visible from the ground, large scale patterns such as these are seen best on satellite photographs Such as the image of Clou Street over the Bering Sea(2nd pic).

The 1st Picture was taken on 18 June 2007 from a Japanese Coast Guard aircraft off the north eastern coast of Hokkaido, shows a bird’s-eye view of cloud streets over the Sea of Okhotsk. According to the Sapporo Meteorological Observatory, these low-altitude stratocumulus clouds were rolled into long, distinctive ribbons after becoming trapped in air currents. While it is not uncommon for wind to form such patterns in stratocumulus clouds, photos that clearly show the clouds rolled into strips are rare.

güttsfükk · #2 02-26-2009, 09:49 PM

i recommend muting for this video as the audio is fucked, or at least turn down the volume before playing it.

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This video provides a rare close-up bird’s-eye view of cloud streets, which are created when convection currents cut low-lying cumulus into long, clean strips. According to the video narration, these clouds floated just over the sea surface, stood 300 meters tall and stretched for over 100 kilometers.