packageflyer

Does anyone have the formula for determing the cloud bases?
Think I heard something like this: Temperature minus dewpoint divided by 4.4, then multiplyed by 1000. It did seem to work.......

multipilot

I believe that's correct, and I want to say for some reason or another that only works with cumulus bases. But I could be wrong.

jared4271987

Yeah this seems to be the same formula I remember. I also remember that there was something in there about cumulus bases but I'm not 100% about that either. Hehe multipilot is an @$$ chief CFI. Sweet.

Krafty1

I believe its 4.4 for Fahrenheit and 2.5 for Celsius

Slice

I use A+T+I+S...works great.

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Photon

think it's 2.2 for celcius?

edit: no I was wrong

Mason32

temp - DP X either 200 (if using C) or 400 (if using F)
If reading temps from a digital ATIS, use the T000000 series of numbers for the exact temp spread.... IE temp 6 C and Dewpoint 7 C in the ATIS can be found again at the end as T056074 meaning 5.6 degrees C temp and 7.4 degrees C on the DP... the difference being 1.8. 1.8 x 200 = 360 feet estimated bases... with just the ATIS 6/7 you'd come up with 200 for the bases and be significantly off....

yes, if you HAVE to be mr perfect, use the 4.4 and 2.2 OR 440 feet and 220 feet per degree.

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Twin Wasp

And that would give you a relative humidity of how much?

Planespotta

Yup, it's (Temperature-Dew Point)/2.5 x 1000

For example, 35 degree Temp, 30 degree DP:

(35-30) = 5 . . . 5/2.5 = 2 . . . 2 x 1000 = 2000 AGL base of clouds

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usmc-sgt

Keep it simple. I use the T.L.A.R method. It is easy and works with most every aviation calculation.

That Looks About Right

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