=MID(A3,6,5)=(1+INT((TODAY()-(DATE(YEAR(TODAY()),1,2)-WEEKDAY(DATE(YEAR(TODAY()),1,1))))/7))&TEXT(TODAY(),"\/yy")

I forgot to credit the author of the Week Number code used in part of the
above Conditional Formatting formula. The "The Excel Analysis ToolPak
function WEEKNUM" write-up on this page...

http://www.rondebruin.nl/weeknumber.htm

credits a Daniel M (too bad we don't have his full name) with developing the
formula equivalent of the Analysis ToolPak's (ATP) WEEKNUM formula (which my
formula assumes Carla used in constructing her Row 3 headers). It was
necessary to use Daniel M's formula because the Conditional Formatting
dialog wouldn't let a formula reference the ATP function directly.

Rick