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General Weather/Earth Sciences Topics => Other Weather Topics => Topic started by: attherubicon on March 28, 2021, 09:38:29 PM

Title: Formula for estimating cloud base. Explanation please
Post by: attherubicon on March 28, 2021, 09:38:29 PM
Iv see this formula in several places for estimating the height of cloud bases:

CB ≈ (T - Td)*1000/4.4

Im puzzled by the 4.4. I would expect a number for the dry adiabatic lapse rate, but Not 4.4
Title: Re: Formula for estimating cloud base. Explanation please
Post by: sky_watcher on March 28, 2021, 09:55:31 PM
Iv see this formula in several places for estimating the height of cloud bases:

CB ≈ (T - Td)*1000/4.4

Im puzzled by the 4.4. I would expect a number for the dry adiabatic lapse rate, but Not 4.4
From the Cloud Base Calculator site:

Quote from: https://www.omnicalculator.com/physics/cloud-base
The rate at which air cools is estimated at 5.4F per 1000 feet of altitude. The dew point decreases slower - at about 1.0F per 1000 feet. That means that per 1000 feet, the spread decreases by 4.4F.
Title: Re: Formula for estimating cloud base. Explanation please
Post by: attherubicon on March 28, 2021, 09:56:46 PM
Thank you.
Title: Re: Formula for estimating cloud base. Explanation please
Post by: CW2274 on March 28, 2021, 10:16:25 PM
Iv see this formula in several places for estimating the height of cloud bases:

CB ≈ (T - Td)*1000/4.4

Im puzzled by the 4.4. I would expect a number for the dry adiabatic lapse rate, but Not 4.4
The rate at which air cools is estimated at 5.4F per 1000 feet of altitude.
Just as an FYI, known as "standard lapse rate".