Rising Mortgage Rates Cloud Housing Market

NEW YORK (TheStreet) -- Watch out, homebuyers.

Thirty-year mortgage rates are once again above 4% -- at 4.1%, according to the BankingMyWay.com Weekly Mortgage Rate Tracker.

That's a fairly significant rise from the 3.8% recorded two weeks ago and light years ahead of the "low 3%" rates recorded at the beginning of 2013.

It's not just 30-year fixed rate home mortgages, either. According to the tracker, 15-year fixed mortgage fates stood at 3.3% late last week, up from 3.1% two weeks ago. And five-year adjustable rate mortgages rose from 2.67% last week to 2.83% this week.

What's behind the rise -- and is it a long-term trend?

Homebuyers will want to know. After all, every extra interest rate percentage point in a mortgage loan comes out of their pocket.

Take a $200,000 mortgage on a 30-year loan with a 3% mortgage rate. According to the BankingMyWay.com Mortgage Loan Calculator, that translates into:

Total payment over 30 years: $303,554.50
Total interest paid over 30 years: $103,554.50
Monthly payments: $843.21

But if that $200,000 loan came with a 4% mortgage rate, those numbers go up -- significantly.

Total payment over 30 years: $343,739.43
Total interest over 30 years: $143,739.43
Monthly payments: $954.83

Economists believe rates are rising for several big reasons, but the improving economy could be reason No. 1.

"Our May forecast predicts that the second half of 2013 will be a little stronger than the first half, despite the slowdown during the past couple of months," says Fannie Mae's chief economist, Doug Duncan, in a recent research statement. "Employment numbers are getting better, albeit it at a relatively slow pace, and the April employment picture should help boost consumer sentiment toward the economy overall. Spending grew in the first quarter at a surprisingly strong pace, and although this rate is unlikely to hold up, consumers continue to show signs of resilience in the face of fiscal concerns."

Another reason: The Federal Reserve is pulling back its support of the U.S. housing market. The Fed has been pumping around $85 billion into the mortgage market on a monthly basis for a few years now, but economists see the handwriting on the wall. With an improving economy, that support should decline starting this fall.

The Federal Reserve can afford to lend money at low rates, but private investors cannot. Thus the need for higher mortgage rates for lenders to step into the breach when the Fed pulls away -- which we're already seeing.

Four percent rates aren't exactly chopped liver. But there's no telling if homebuyers will see 3% mortgage rates again.

Fannie Mae certainly doesn't think so -- Duncan is saying those days are most likely gone forever.