Rising mortgage rates, inventory shortages and declining unemployment are pushing buyers into what is already an "extremely competitive housing market," said OB Jacobi, a member of the board of directors for Northwest Multiple Listing Service. 

The MLS system covers 21 counties in Washington state.

The latest data from the MLS revealed pending sales during June rose 10.6% from one-year prior, indicating a scramble from buyers looking to lock in loan rates and bid on an already shrunken supply of homes. 

Members within the 21 counties served by Northwest MLS documented 9,484 mutually accepted offers last month, outgaining the year-ago number of pending sales by 907 transactions. 

"In June, our brokers reported anywhere from 2-to-7 offers on homes in the lower to mid-price ranges," said Jacobi, president of Windermere Real Estate Company in Seattle. 

Jacobi noted that interest rates for 2013 reached a new high in mid-June, likely due to improved confidence in the U.S. economy. "And now, with Seattle’s jobless rate below 5%, we expect even further pressure on housing as new workers move to the area," he added.

In the first six months of 2013, there were 35,115 completed transactions year-to-date, surpassing the figure of 29,777 for mid-year 2012. This totals a 17.9% year-over-year increase.

Home prices continued to rise as well, with the median price for last month’s closed sales in the area coming in at $279,950, a 9.8% increase from the year-ago figure of $255,000.

Single-family home prices increased more than 8%, from $268,162 to $290,000. Meanwhile, inventory shortages continued to plague buyers, with only about 2.5 months of supply system-wide. 

J. Lennox Scott, chairman and CEO of John L. Scott Real Estate noted that with interest rates continuing to increase, more resale listings are coming on the market. 

"Many potential sellers are nor realizing if they are going to purchase another home, they will be purchasing at a higher interest rate, so they are choosing to move forward now," Scott continued. "The additional inventory is appreciated by the backlog of buyers trying to purchase a home, though we are still in a quick action market."