Isolated thunderstorms have begun to develop late this afternoon over parts of western Oklahoma and far north Texas. The storms are developing in the vicinity of a dryline which extended from a surface low in far northwest Oklahoma...southward through the Altus area...to near Vernon Texas. Other storms were developing near a warm front extending eastward from the low along the Kansas Oklahoma border. A very unstable airmass is in place ahead of these boundaries and combined with favorable deep layer shear will support the development of severe storms. Large hail and damaging winds will be the main threats. The storms are expected to become more numerous during the evening and may converge into one or more storm complexes which will then move southeast through the area. As this occurs the threat for damaging winds will increase.