Cherry harvest has begun in Mid-Columbia orchards, and so far there are signs it could be a good year grower.  Oregon State University Extension horticulturist Ashley Thompson says good weather leading up to harvest has helped the crop.  She says it a medium-sized crop, with good sizing.    Chelan cherries were being harvested this week in The Dalles area, and Thompson says Bing cherries are about ten to eighteen days out.  She noted Upper Valley growers are a bit behind that timeline, but they have also been doing harvesting.  Thompson says the domestic market is the largest for cherries, but many will end up in Canada and Southeast Asia.