A push of cool air and warm, moist air will clash over the northeastern United States to end this week and the first weekend of May, AccuWeather meteorologists say. In addition to a strong temperature contrast from east to west, conditions will range from sunny to rainy and even thundery, all in a span of 100 miles. Thursday may very well be the best day of the week for outdoor plans for the Northeast region as a whole. A high pressure area will first nose southward over the Maritime Provinces o