The Mage Storms Trilogy
Book 2: Storm Rising

The threat of war from the powerful Eastern Empire has forced the kingdom of Valdemar into an uneasy coalition with its ancient enemy, the neighbouring kingdom of Karse. But as mysterious mage storms threaten all the kingdoms of the West, even these combined magical resources may be enough. For unless the source of these storms can be found and destroyed, their entire world may perish in a final holocaust. The sequel to Storm Warning.