Westchester county sales volume essentially stabilized as listing inventory edged higher. The number of countywide sales slipped a nominal 0.4% to 1,640 from the prior year quarter. However the number of total sales under contract surged 16.3% to 2,338 over the same period. This increase was brought about by a 19.2% jump in signed contracts to 1,928 during the first quarter as compared to the same quarter last year. A robust New York City economy and falling affordability there have pushed county housing demand higher…