VLOOKUP using two parameters

This seems simple enough, but it's causing me a lot of grief!

I have two spreadsheets with weather type data:

The first has the following columns "Station" and "Date". This sheet has random days over a few years.

The second has three columns "Station" "Date" "Visibility". This sheet has every single day over the last few years.

What I need to do is extract the visibility value from the second worksheet based on the station and date of the first sheet. So, for example, I have Station "Alpha" on 20040501. I need to search based on those parameters in the second sheet and pull the visibility value for that day. This needs to be automatic because the actual file I have contains about 7000 records so it would take forever to do manually! See attached sample file

Thanks in advance!