National Weather Service offices in Boulder and Pueblo are warning residents of the eastern half of Colorado to be alert for possible flash flooding Sunday afternoon as monsoon humidity continues to pour through the state .
Flood watches are expected to be in effect as early as 12:00 a.m. from Larimer and Weld counties in the north-central portion of the state to Las Animas County along the New Mexico border. Kit Carson, Cheyenne, and Kiowa counties along the Kansas border mark the eastern limit of watches in the state. Late Sunday morning, Bent and Prowers counties were added to the watch zone. The watches may remain in effect until 3:00 a.m. Monday for Eastern counties.
Strong to severe slow-moving thunderstorms are possible early to mid-afternoon, with some capable of producing one to two inches of rain in less than an hour. Some areas can see up to three inches of rain. Storms will develop along the Colorado foothills, spreading to the eastern plains as the afternoon progresses.
Thunderstorm activity is expected to continue well into the evening, particularly over the plains.
Along with heavy rain, storms in east central counties could produce wind gusts of up to 70 miles per hour. Isolated Landspout tornadoes are also possible, while the potential for hail is limited.
According to the NWS Weather Prediction Center, there’s a 15% chance that rainfall amounts will exceed flash flood forecasts across much of eastern Colorado on Sunday.
Outside of thunderstorms, the east-central part of Colorado could see between a quarter and an inch of precipitation.
Flash flooding on recent fire burn scars is of particular concern. The NWS Pueblo office notes significant risk to Spring, Junkins and Hayden Pass scars as of 6:00 p.m. Sunday. The risk continues for the Spring and Junkins scars until midnight, while the risk for the Hayden Pass scar drops to limited around 9:00 p.m.
Further north, the NWS Boulder office notes a high risk of flooding at Cameron Peak and Calwood burn scars from 12:00 p.m. to 10:00 p.m.
In southeastern Colorado, the NWS Pueblo office expects the threat of heavy rain to spread south and east this evening into the southern mountains and southern Interstate Corridor region. 25, as well as the eastern plains, probably seeing the heaviest rainfall. The greatest amounts are likely to fall during the evening hours, with the threat of heavy rain diminishing by early morning.
The NWS reminds people to stay informed about today’s weather conditions and to have multiple ways to receive updates as conditions change. Never attempt to cross flooded roads.