The Federal Reserve Open Market Committee last met Dec. 16. In the following weeks, rates surged briefly before plunging to near historic lows, according to Bankrate's weekly survey.

Although rates reversed course and began to climb again last week, they remain well below 6 percent.

Bob Walters, chief economist at Quicken Loans, says the Federal Reserve is determined to keep rates low. As part of that effort, the Fed recently began to buy up the first of $500 billion in mortgage-backed securities it intends to purchase between now and June.

The Fed's actions push prices for these securities higher, which in turn causes mortgage rates to fall. The Fed also has signaled it may purchase large amounts of Treasuries to put additional downward pressure on mortgage costs.

"They are buying as much long-term government debt as they can to keep those interest rates low," Walters says.

Cameron Findlay, chief economist at LendingTree.com, also believes the Fed will do what it can to keep rates down.

The Fed's moves are part of a bigger effort to get the economy back on track and to avoid a repeat of Japan's "lost decade" of economic stagnation that began in the 1990s, Findlay says.

"The Fed will use every tool in the box to force a turnaround quickly," he says. "They are determined to learn from the mistakes Japan has made."

Walters is hopeful the Fed's efforts will depress mortgage rates in the short run.

"We throw numbers like $500 billion around so easily now," he says. "That's just massive, massive, ungodly amounts of money. Essentially it's like saying they are putting 5 percent or 4 percent of GDP toward driving mortgage rates down."

Still, he cautions that people should not necessarily expect rates to fall much further.

"We might just stay in this range for a while," he says.

Dan Green, a Cincinnati-based Certified Mortgage Planner and author of TheMortgageReports.com, agrees that the Fed's efforts should help keep rates "closely tethered to their current levels."

Lower rates "for the near future" is also the forecast of David Kuiper, a mortgage planner at First Place Bank in Holland, Mich.

Fannie Mae fees
However, Findlay sees a growing risk of climbing mortgage rates, thanks in large part to increased loan fees announced late last year by Fannie Mae that are scheduled to take effect April 1.

As part of these changes, Fannie Mae is tacking on higher fees for loans that meet certain risk criteria. Fannie Mae buys or guarantees loans from lenders, and the fees apply to these loans.

Lenders typically pass these higher costs on to their customers. A borrower's credit score and loan-to-value, or LTV, ratio play a large role in determining how much he or she will pay in new fees.

Fees also may be higher for borrowers who:

• Have second mortgages or interest-only mortgages. • Finance a two-unit property. • Finance a condo or co-operative with a loan-to-value ratio of more than 75 percent. • Apply for a cash-out refinance.

Although the increased charges are not due to take effect until April 1, some lenders are already adjusting their pricing. That's because it can take more than two months for a lender to complete the process that begins with closing a loan and ends with selling it to Fannie Mae.

"Banks are already aligning their (rate) locks today," Findlay says.

Walters says such activity is widespread among lenders, including Quicken Loans. "Most mortgage lenders like us are putting that into effect right now," he says. "And that is going to be felt."

Green sees an irony in the fact that the Fannie Mae increases are coming online just as the Fed is making strenuous efforts to push rates down. "What the Fed giveth, Fannie Mae taketh away," Green says.

What should you do?
Regardless of where rates are headed in the short-term, now is the time to look for a new mortgage, Findlay says. "Borrowers who try to pick the bottom of the market will likely miss the lowest levels they will see in their lifetime," he says.

To get the best rates, borrowers will need sound financials, such as FICO scores of at least 720 and a loan-to-value ratio of 80 percent or better, Findlay says.

Walters agrees that today's low mortgage rates and falling home prices represent a rare opportunity. "All my friends and family who ask me, I tell them that right now is the time to go (get a mortgage)," he says. "We haven't seen 30-year rates like this ever in the modern era."

Certain types of buyers, such as first-time purchasers, are especially likely to benefit from the current environment. "If you're a first-time homebuyer, you just picked the perfect time in American history to go buy a house," he says.

However, not everybody will be invited to the mortgage party. People with credit scores below 700 or little equity will not get the best rates, Walters says.

"If you've got really good credit and equity, this is one heck of an opportunity," he says. "If you don't, sadly you're not going to be able to participate in the fun."