Predicting winter storms is easy; the hard part is knowing whether they'll dump rain, hail, or powdery snow—and how much. It's more straightforward in the West than the East, because storms lumber across the Pacific for several days before slamming into the snow-friendly Sierras. For Atlantic storms, the best powder conditions occur when warmer low-pressure zones, like a stalled nor'easter, remain offshore, reducing the temperature and moisture content of inland snowfalls. Either way, "four or five days in advance, you should have a pretty good idea if you're going to see a snowstorm," says Weather Underground's Shaun Tanner. So when to pull the trigger on plane tickets? To travel on Friday, look at storm forecasts for your favorite resorts on Monday and Tuesday. Just after midnight Tuesday (when fares go on sale), pick the most promising powder destination and book your ticket to arrive at least half a day before the dump. Two days before a storm hits, meteorologists can generally narrow its start time to a six-hour window. Within one day, a good forecast can pinpoint the three-hour period when the flurries will fly. Plan to arrive early, however: Flying in a blizzard is nothing like skiing in one.
Filed To: Science