Match nearest weekly date to monthly series, leaving other weeks blank

I have a series of month-end values like this:

Apr-15	May-15	Jun-15	Jul-15	Aug-15	Sep-15	Oct-15	Nov-15	Dec-15	Jan-16	Feb-16	Mar-16
152	149	154	163	161	168	169	166	166	161	157	157

I also have a separate weekly series. I want a formula that will automatically take the value from the monthly series in the week that most closely matches the month end date. And I want the remaining weeks to stay blank so that I can plot the time-series, connecting the data points with a line.

My series would look like this:

12/04/15	19/04/15	26/04/15	03/05/15	10/05/15	17/05/15	24/05/15	31/05/15	07/06/15	14/06/15	21/06/15	28/06/16
			152				149				154

etc...

Can anyone help me come up with a formula for the weekly data series that will pull out the matching value from the monthly series, but leave the other weekly values blank?

Many thanks

For testing, I copied your top table to A1:L2 and your bottom table to A8:L8, adjust the ranges in the formula to suit your actual sheet layout.

In A9

=IF(MIN(EOMONTH(A$8,0)-A$8,DAY(A$8))<=3,LOOKUP(EOMONTH(A$8,-1+(DAY(A$8)>3)),$A$1:$L$1,$A$2:$L$2),"")

Does that help?

That works perfectly - thank you!