Going through my deceased grandfathers posessions, I found a silver
cigarette case, with the following inscription:
To Allen from Ruy
LBN TML FCS 1944/45 STOP CLEAR 2 SCCU 25 60 2 AS 120 WIND NW 12 VISBY 8 STOP NO FOG

It was given to my grandfater (Allen) in Lisbon. My grandfather was
there training meterologists to serve at airports in africa after
WWII.

Appears to be from a telegram giving Lisbon Airport weather conditions:

Lisbon Terminal Forecast 1944/45
20% Scattered Cumulus at 2,000' and 6,000'
20% Alto Stratus at 12,000'
Wind out of the northwest at 12 knots
Visibility 8 miles, no fog

The "20%" is a best guess.
The "stop clear" is probably a telegram character, as in  "stop" and
"full stop" since "clear sky" is usually abriviated "clr"

Actually, the 2 indicates 2 8ths of the visible aerodrome.  This would
mean 2/8 of the sky is obscured by stratocumulus/cumulus at 2,500' and
6000' and 2/8 of the sky is obscured by altostratus at 12,000'  The
reason it is broken down like that is that 2,500 and 6,000 would both
still be considered lower etage clouds, while 12,000 is definately a
mid-etage cloud.  Thus the separation between the levels.  (I am a
weather forecaster for the military)  The rest of your analysis is
right on.