# Decoding the ECMWF

• Curious as to how to read these numbers at the bottom. Looking to figure out cloud heights and if these mean anything in relation to them. Also is there a way to figure out visibility?

• The blue bars? This is just precipitation rate (blue for rain as per the legend on the left) – so 0.2mm/hr of rain is forecast at 00:00 on Monday in your image. Cloud base is just below that, e.g. forecast cloud base is 23,000ft at 00:00 on Monday. Change the units by clicking on them.

• @johnckealy
Developers must consider put the "mm" symbol a little lower.
(and change it to "mm/hr" or "mm/3hrs" or mm/6hrs" beyond day5)

• I appreciate the feedback it helped a lot. To further my knowledge I have additional question of defining the gray portions of the picture in line with the 900h 900m 3000ft. So on Monday at 1800 I see the .6 that and the .3 are dark portions and it slowly lightens up after .3. What are these portions as we as the ones about them depicting? Also what is the meaning of the 900h 900m 3000ft and above that? Again thanks for any additional information.

• @zdawg801 – The gray areas represent cloud. Darker grays = cloudier skies. Since this is a time series, the "edges" of these shapes from left to right represent cloud formation and dissipation.

The numbers show the cloud level. The "h" should really be "hPa" – this is atmospheric pressure, which decreases with height. Then km is just kilometers, and ft is feet. "FL" means flight level, where FL180 = 18,000 ft, or FL300 = 30,000 ft.

So for example, at 1500 Monday, there is broken/overcast cloud with a cloud base of 12,000ft; this cloud is deep enough to stretch up past the 30,000 ft mark; it's giving 1.8mm of rain per hour, and it appears to be thickest at the level of 500hPa, which equates to 5km, which equates to 18,000ft.

Make sense?

• @johnckealy yes super helpful thanks a lot!