In the remarks section, it says "FG5" which means the obscuring
phenomenon is 5/8 fog. For an obscuring phenomenon to be considered a
ceiling it needs to be 8/8. Therefore the answer is c because 5/8 + 3/8
= 8/8.

John

Markus wrote:

Having trouble with an IFR test question;
It reads,
What is the minimum increase in opacity of the surface based layer at
Fredericton (YFC), in order for it to constitude a ceiling?
METAR CYFC 132100Z 260010KT 2SM -RA BR BKN090 08/07 A2953 RMK
FG5SC1 SLP994

Choices:
a) none, it alreadi constitudes a ceiling
b) 2/8
c) 3/8
d) 1/8

The answer is c.
Anyone know why?