Foreclosure filings in the Washington region dropped by more than half in the first three months of the year, but an uptick in March foreclosures indicates the region isn’t out of the woods yet. Of the more than 6,600 foreclosure filings in local jurisdictions during the first quarter, March accounted for between 40 percent and 50 percent of filings, according to a report by foreclosure tracking firm RealtyTrac. Many experts had predicted that states would see an increase in filings during the first half of 2011 as the national investigation into the foreclosure process wound down.