This updated and enhanced Fourth Edition of ESSENTIALS OF METEOROLOGY is written by the most widely read, trusted author in introductory meteorology. Ahrens' ability to explain relatively complicated ideas in a student-friendly, manageable fashion allows even non-science students to visualize the principles of meteorology. Introductory stories at the beginning of each chapter draw students naturally into the discussion while "Did You Know?" sections highlight interesting weather facts and recent meteorological events. Updated material in this edition includes new Weather Watch and Focus boxes, as well as updated art, maps, and figures. The package of teaching and learning tools to accompany this text will now include course management, and a FREE, brand-new, student tutorial system - MeteorologyNow. MeteorologyNow is Web-based, assessment-driven, completely flexible, and contains a wealth of book-specific interactivities. It also offers a personalized learning plan based on each student's assessment results, helping the student focus on the concepts they don't yet understand. This complete teaching package provides each student with fun, interactive learning opportunities and an even greater chance for success.