According to the July 4, 2017, U.S. Drought Monitor, moderate to extreme drought covers 8.5% of the contiguous United States, an increase from last week’s 8.0%. Extreme drought also expanded to cover over 1.4% of the Lower 48, up from 1.0% last week. But, exceptional drought—the worst category—continued to remain absent for the 24th consecutive week.
An upper-level high pressure ridge dominated the West this U.S. Drought Monitor week, keeping the weather dry and warmer than normal. Upper-level weather systems moving through the ridge intensified as they dropped into an upper-level trough over the eastern United States.
Surface lows and cold fronts associated with these weather systems brought below-normal temperatures to most of the central and eastern contiguous United States along with areas of rain. Above-normal rainfall contracted drought and abnormal dryness in parts of the Southern Plains and Southeast, while continued warmer- and drier-than-normal weather prompted expansion of drought and abnormal dryness in parts of the Northern Plains and West.