Time: 218 PM Thu June 24, 2021 Forecaster: Brad Simmons ------------------------- Internal Message Status Flash Flood Prediction Program ------------------------- MESSAGE 1'S ISSUED FOR THE ENTIRE DISTRICT - Message 1's have been issued for the entire District and will be valid until 9pm this evening. - Modest surface moisture and a passing upper level disturbance will result in a round or two of showers and thunderstorms this afternoon and early evening over the District. Individual thunderstorms will be relatively fast moving from SW to NE at 20-25mph which will keep the majority of the moderate to heavy rainfall brief. The greatest threat for extended periods of heavy rainfall will be from "training" of multiple thunderstorm cells over a single location. Strong thunderstorms may also become severe with gusty winds and large hail being the primary threats. - Best chances for thunderstorm activity will be through about sunset with additional rain showers possible into the evening. STORM RAINFALL POTENTIAL AND DURATION: Moderate to strong thunderstorms will produce 0.3-0.8" of rain in 10-30 minutes. WORST CASE SCENARIO: Training of thunderstorm cells may result in up to 1.6" of rainfall in 30-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Boulder County 1 Current TO 900 PM 300 PM TO 800 PM Jefferson County 1 Current TO 900 PM 300 PM TO 800 PM Broomfield County 1 Current TO 900 PM 300 PM TO 800 PM Douglas County 1 Current TO 900 PM 300 PM TO 800 PM Adams County 1 Current TO 900 PM 300 PM TO 800 PM Denver County 1 Current TO 900 PM 300 PM TO 800 PM DIA 1 Current TO 900 PM 300 PM TO 800 PM Arapahoe County 1 Current TO 900 PM 300 PM TO 800 PM the City of Aurora 1 Current TO 900 PM 300 PM TO 800 PM Arvada 1 Current TO 900 PM 300 PM TO 800 PM Wheat Ridge 1 Current TO 900 PM 300 PM TO 800 PM Lakewood 1 Current TO 900 PM 300 PM TO 800 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Arapahoe Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Boulder Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Broomfield Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Denver Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Douglas Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Jefferson Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Foothills above 6500ft       Boulder Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Douglas Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Jefferson Current TO 900 PM THU 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED MONITOR NATIONAL WEATHER SERVICE FOR SEVERE WEATHER STATEMENTS. MHFD Flood Prediction Center: 303-458-0789    F2P2 Website [http://udfcd.org/Flash+Flood+Prediction+Program]