Flash Flood Prediction Program

Time: 301 PM Sun June 27, 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. - There has been enough daytime heating to initiate thunderstorms which will have the potential to produce brief moderate and heavy rainfall through the afternoon. N to S storm motions of around 15-20mph will keep the majority of the heavier rainfall brief. Training of thunderstorm cells or a large, slower moving thunderstorm will have the potential to produce extended periods of heavy rain that may lead to excessive runoff. - Best chances for thunderstorms will be through about 8 or 9pm then lighter rain showers will continue likely into the evening. STORM RAINFALL POTENTIAL AND DURATION: Rain showers and weak thunderstorms will produce 0.1-0.3" of rain in 10-30 minutes. Moderate to strong thunderstorms will produce 0.3-0.8" in 10-30 minutes. WORST CASE SCENARIO: Training of thunderstorm cells or a large, slower moving thunderstorm will have the potential to produce up to 1.6" in 45-60 minutes. COUNTY MESSAGE VALID TIMES PRIME TIME Arapahoe County 1 Current TO 900 PM Current TO 800 PM DIA 1 Current TO 900 PM Current TO 800 PM Denver County 1 Current TO 900 PM Current TO 800 PM Adams County 1 Current TO 900 PM Current TO 800 PM Douglas County 1 Current TO 900 PM Current TO 800 PM Jefferson County 1 Current TO 900 PM Current TO 800 PM Broomfield County 1 Current TO 900 PM Current TO 800 PM Boulder County 1 Current TO 900 PM Current TO 800 PM Lakewood 1 Current TO 900 PM Current TO 800 PM Wheat Ridge 1 Current TO 900 PM Current TO 800 PM the City of Aurora 1 Current TO 900 PM Current TO 800 PM Arvada 1 Current TO 900 PM Current TO 800 PM County-specific Quantitative Precipitation Outlook PRECIPITATION TIME 30-Minute Rainfall and % Probability Message Potential Plains       Adams Current TO 900 PM SUN 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Arapahoe Current TO 900 PM SUN 0.1" (95%) to 0.3" (75%) to 0.8" (35%) ISSUED Boulder Current TO 900 PM SUN 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Broomfield Current TO 900 PM SUN 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Denver Current TO 900 PM SUN 0.1" (90%) to 0.3" (60%) to 0.8" (30%) ISSUED Douglas Current TO 900 PM SUN 0.1" (100%) to 0.3" (75%) to 0.8" (35%) ISSUED Jefferson Current TO 900 PM SUN 0.1" (100%) to 0.3" (80%) to 0.8" (40%) ISSUED Foothills above 6500ft       Boulder Current TO 900 PM SUN 0.1" (100%) to 0.3" (70%) to 0.8" (40%) ISSUED Douglas Current TO 900 PM SUN 0.1" (100%) to 0.3" (80%) to 0.8" (50%) ISSUED Jefferson Current TO 900 PM SUN 0.1" (100%) to 0.3" (80%) to 0.8" (50%) 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]