Whether the question is yes or no the answer probably will not have much of an affect on your current or future mortgage. There are some exceptions, however, which I will enumerate shortly. The problem, as I see it, is there could be great disappointment no matter which way the Federal Reserve goes on the 18th of this month. For the school of optimism that definitely sees a cut in the near future, there may not be a matching drop in mortgage rates.
If there is a drop in rates it will be in conforming loans that have a maximum size of $417,000 for single family houses (except in Hawaii and Alaska), and higher for units up to a maximum of four. The conforming rates generally follow the 10 year treasury note, but not lately. Even if the Fed cuts there isn't even a guarantee that the 10 year treasury note will go down.
There is precedent for the above statements. First, while the Fed. was raising interest rates the 10 year rarely moved higher and really didn't react until the last one or two increases.
Secondly once the last raise was firmly in place and the 10 year moved to over 5.25%, the subsequent drop wasn't entirely mirrored by the mortgage rates. In fact once the credit squeeze occured in August the conforming mortgage rates barely budged when the 10 year dropped an additional half of one percent (.5%). The jumbo's went up.
The cut will not help the jumbo mortgage rates. Jumbo mortgages are bundled and sold as securitized mortgages on Wall Street and the lowering of the short term rate will not be enough, in itself, to fix the problems in the credit markets. It's major help will be with the confidence of the investors who purchase the bonds and the fact as treasury bonds, bills and notes go down in interest the other investments, securitized mortgage instruments, become more attractive. Home equity lines of credit will most likely drop a corresponding amount to the Federal Reserve because they are tied to the prime rate and it will go down generally equal to the cut in Federal Funds rate.