If you've been watching mortgage rates for the past few weeks and have begun believing that they'll never get out of the 15 to 16 percent brackets, you're wrong.

Despite all the gloom, doom and belly-aching in the housing finance market right now, there are signs that rates to consumers will be somewhat lower by mid-summer.

How much lower -- by one percentage point, by two or even more -- is a matter for debate among housing industry economists. But consider a few of the factors that point to a gradual softening in mortgage costs.

First, the very structure of the home loan is on the verge of a major change that should lead to competitive interest-rate discounts by lenders. The adoption last week of new "adjustable rate mortgage" regulations by the Federal Home Loan Bank Board -- following on the heels of a similar move by the U.S. Comptroller of the Currency -- should hasten the phase-out of the high-cost, fixed-rate mortgage and bring fresh new capital into the housing finance sector.

The long-term, fixed-rate mortgages that most thrift institutions and banks offer today carry the high rates they do in part because the loans are "front-loaded" with an inflation premium of 1 to 2 percent.

An S&L that wants 16 3/4 percent for a standard 30-year, 80 percent mortgage today has tacked an inflationary risk surcharge onto its price. Given the average cost of money to the S&L via deposits (which might be in the 11 1/2 to 12 percent range overall), the S&L could probably charge at least 1 to 1 1/2 percentage points lower rates to home buyers if it didn't have to worry about the impact of future inflation on its fixed rate.

And that's where the adjustable-rate mortgage comes into the picture. Once S&Ls and banks begin their expected wholesale switch to these new mortgage instruments in the coming months, there is a strong possibility of rate discounting of 1 to 2 percentage points below what would otherwise be charged for fixed-rate loans.

Evidence that this is on the horizon comes from individual S&Ls and banks, as well as their industry spokesmen.

"I can easily foresee a competitive pricing situaiton in the summer that will be attractive to consumers," says James Christian, chief economist for the U.S. League of Savings Association. "There's no question in my mind that the adjustable-rate mortgage is going to lead to better rates -- perhaps by as much as 200 basis points (2 percent) when things really get rolling.

"Once a lender knows he's got protection against even the scariest inflation scenario -- in other words, he knows that his mortgage customers will at least be sharing the economic risks with him -- then there's no valid reason why the lender shouldn't reflect the decrease in risk with a decrease in his charges to the home buyer."

E. Stanley Enlund -- chairman and chief executive officer of one of Chicago's major home lenders, First Federal S&L -- agreed with Christian's assessment, with one qualificaiton. Enlund said he could see the possibility of offering the forthcoming adjustable rate loan at 1 to 1 1/2 percentage points below the regular market, but he cautioned that greater deposit inflow to S&Ls would be needed to enable the industry to cut prices any more than that.

"If you're looking for 13 percent rates this year," said Enlund, "We've got to get back some of the dollars that are sitting in (Wall Street's) money market funds."

Whatever the magnitude of the rate break that's coming with the switch to the adjustable-rate mortgage -- whether it means 12 1/2 percent rates or 14 percent rates -- the important fact is that costs to consumers should be lower.

There are other encouraging economic signs as well, despite the recent, temporary run-up in short-term interest rates.

For example, the rate of inflation in the overall U.S. economy shows a downward trend, into the 10 to 11 percent annual range during the past two quarters. If the trend continues for another quarter or two, it should exert a downward push on long-term interest rates, particularly mortgages.

So, too, should the basic softness in the economy -- pointing to lower credit demands by private industry -- and the relatively light calendar of U.S. Treasury borrowings in the capital markets during the immediate months ahead. With less business chasing capital funds, and with even modest inflows of savings deposits to the thrift institutions in the next three to six months, mortgage rates could be surprisingly lower by late summer.