Lousy skiing and bad apples.That's what Pacific Northwest residents may be able to expect in 80 or so years.While global warming usually is seen as fairly simple event-few er cold days in the winter,a few more 100-plus-degree days in July-its regional implications could be far more dramatic.That's what climate researcher Ruby Leung of the Pacific Northwest Nation Laboratory in Richland,Washington,found when she ran computer models to study the impact of a warmer climate on Oregon and Washington.Her conclusion:precipitation that now falls in the mountainsas snow from late November through late March will turn to rain,raising the average snowline from today's 3000 feet to 4100 feet.That will turn now-popular ski resorts in the central Cascade Mountains into miserable aqua-parks.Itwill cause problems forfarmers on the dry east side of the mountains who rely on sping and summer snowmelt to irrigate their apples and wheat.Andflooding-now common in November when storms wash ashore-could be sever throughout the winter.