The National Weather Service (NWS) issued a Severe Thunderstorm Watch for large portions of Colorado, Nebraska and Wyoming through 10 p.m. MDT Wednesday, and followed with a rapid succession of warnings as powerful storms developed along the Front Range and eastern plains. NWS offices in Boulder and Pueblo warned that storms moving across Boulder, Jefferson, Douglas, El Paso, Pueblo and neighboring counties would produce wind gusts of 60–70 mph and hail ranging from two inches in diameter to tennis-ball and baseball size. Communities placed under warnings through 7 p.m. MDT included Arvada, Castle Rock, Fountain, Calhan, Pueblo County and Huerfano County, among others. In addition to the hail and damaging winds, forecasters highlighted the risk of torrential rainfall. A Flash Flood Warning was posted for Colorado City, Cedarwood and Greenhorn until 9:30 p.m. MDT as slow-moving storms threatened low-lying areas. Residents across the warned regions were advised to seek sturdy shelter, remain away from windows and be prepared for rapidly changing weather conditions into the evening.