Very hot, dry, and unstable conditions will be prevalent across much of the West peaking along thermal trough(s) in California into the Northwest and Great Basin. Widespread temperatures over 100°F are expected, including much of the Central Valley and surrounding foothills above 110°F. Minimum relative humidity will be 3-15% across much of the West and breezy winds are likely to develop in portions of northeast California into southern and central Oregon and in portions of Wyoming. Near record Hot, Dry, Windy Index values are expected across the northern half of California and much of southern and central Oregon as well. Existing and any emerging new fires in these areas will be very active, with increased activity expected on most if not all existing large fires. Isolated mixed wet and dry thunderstorms are possible in the southern and central Sierra into western Nevada and from southwest Colorado into portions of Arizona and southern California over the higher terrain. Scattered thunderstorms and showers are likely from the Gulf Coast through much of the Southeast Ohio Valley and Mid-Atlantic into the Northeast. Heavy rain is likely from the DelMarVa through New Jersey and Connecticut.